SCHOOL OF
ENGINEERING AND
APPLIED SCIENCE
HEALTH AND
SAFETY
HANDBOOK
MED Version October 2012
USEFUL CONTACT TELEPHONE NUMBERS
EMERGENCY ONLY (SECURITY)
From an internal phone
From an external phone (landline)
From a mobile phone
2222
0121 204 2222
0121 359 2922
SECURITY MAIN CONTROL
4803
HEALTH CENTRE
Halcyon Medical (formerly Aston University Health Centre)
has moved to new premises on the lower ground floor of
Boots the Chemist, 67-69 High Street, Birmingham, B4 7TA
(opposite Marks & Spencer).
0845 0724632
UNIVERSITY SAFETY ADVISER
- Andrew Vickers
4742
ASSISTANT UNIVERSITY SAFETY ADVISER
- Darnette Cowan
4743
SITE RADIATION OFFICER - Kevin Hughes
3963
UNIVERSITY WASTE DISPOSAL OFFICER
- Dave Aveston
3376
HEAD OF SECURITY – Mark Sutton
4804
FIRE SAFETY ADVISER – Dave White
4805
ESTATES HELPLINE
4328
SCHOOL (EAS) SAFETY ADVISER – Steve Ludlow
3406
CEAC SUBJECT GROUP SAFETY ADVISER
- Dr. John Fletcher
3389
CS SUBJECT GROUP SAFETY ADVISER
- Dr Joanna Lumsden
3470
EAS WORKSHOPS SAFETY ADVISER
-Mark Turner
3602
EE&PE SUBJECT GROUPS SAFETY ADVISER
-Andy Abbott
3482
ESM SUBJECT GROUP SAFETY ADVISER
-Fatemeh Miri
3576
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FIRE & OTHER EMERGENCY PROCEDURES
Staff and students should be made aware of any local rules and requirements relating to their
particular building or work area that may differ from the general information given below.
During an evacuation (in response either to a real emergency or to a fire drill - which can be either
announced or unannounced) all evacuees must exit the building as quickly as possible using the
signed escape routes and following any instructions given to them by security staff,
Departmental/School Fire Wardens or members of the emergency services.
IF YOU DISCOVER A FIRE
1. IMMEDIATELY operate the nearest fire alarm call point
2. From a place of safety, contact security by dialing:
 222 from any internal phone, or 2222 if phoning from residences
 0121 359 2922 if calling from a mobile phone or 0121 204 2222 from a landline
 DO NOT DIAL 999
 Speak clearly, giving the location of the fire, your name and any other details as requested by
Security - do not ‘hang up’ until told to do so!
3. Only fight the fire if you have been trained and it is safe to do so
4. Evacuate IMMEDIATELY using the nearest available fire exit (see evacuation procedure
below)
5. Report to the designated fire assembly point (see list below)
IF YOU HEAR A FIRE ALARM
1. Evacuate IMMEDIATELY using the nearest available fire exit (see evacuation procedure below)
2. Report to the designated fire assembly point (see list below)
EVACUATION PROCEDURE
1. Evacuate IMMEDIATELY using the nearest available fire exit, observing the following advice:
 DO NOT STOP TO COLLECT BELONGINGS
 DO NOT USE LIFTS
 DO NOT RE-ENTER THE BUILDING until authorised by security or fire officer in charge
2. Report to the designated fire assembly point (see list below)
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DESIGNATED FIRE/EMERGENCY ASSEMBLY POINTS
Main Building, North & South Wings, Library, Vision Sciences, Academy Building, Nursery and
Woodcock Sports Hall - VAUXHALL/LAKESIDE PARADE
Chemical Engineering, Gem Sports Hall and all Residences Buildings - CAR PARK No 6
Lakeside Conference Centre and Student’s Guild - LIBRARY BOULEVARD
Nelson Building (Aston Business School) - CAR PARK No 3
FIRE ALARM SYSTEMS
The Main Building has a two-stage fire alarm system:
 Stage 1: an intermittent single-tone alarm indicating that a fire alarm call point has been activated
or a potential emergency has been reported to security; anticipate a full evacuation by ceasing
normal work activities and, for example, storing any hazardous materials safely and switching off
power tools
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Stage 2: a continuous two-tone alarm - Evacuate IMMEDIATELY (see procedure above).
All other buildings have single-stage alarms - Gem and Woodcock Sports Halls and the Chemical
Engineering Building have traditional bell alarms, the remainder have two-tone electronic alarms.
Evacuate these buildings IMMEDIATELY the alarms sound (see procedure above)
OTHER EMERGENCIES WHICH MAY REQUIRE EVACUATION
In the event of other emergencies, for example, a serious chemical spillage, gas leak, or the discovery
of a suspicious package, contact Security for further advice on the telephone numbers listed above.
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IN THE EVENT OF AN ACCIDENT OR ILLNESS AT WORK
Notify a First Aid Officer and cooperate with that person. If no First Aider is available
contact the Security Office should be contacted for assistance and advice using the
emergency internal telephone extension 2222.
Give the following information:
i The location of the ill/injured person
ii The nature of the illness or injuries
iii The extension number of the internal telephone
If the First Aider considers that medical help is required the Security Office should be
contacted, ext. 4222, for direction to the Accident & Emergency Department of a local
hospital or to call the ambulance service.
IMPORTANT NOTES

The Health Centre does not normally provide medical services for students, staff ,
conference delegates or visitors who are not registered with the practice.
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Each area has a number of First Aiders, who are in charge of First Aid boxes and
whose names are posted in prominent positions. Get to know where your local First
Aiders and First Aid boxes are.
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First Aiders have undergone formal training and assessment in dealing with
emergency situations.
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All Security Officers are qualified First Aiders.
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All accidents must be recorded on a University Accident Report Form.
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There is an official University web page http://www1.aston.ac.uk/staff/safety/staffarea/emergency-arrangements/first-aid/ which deals with First-Aid.
...........................................................................................
ENTER DETAILS OF YOUR LOCAL FIRST AIDER HERE:
First Aider Name
......…...........................................…
Location
…....................................................
Phone number
.........................................................
.
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SCHOOL PROCEDURES FOR SERIOUS AND IMMINENT DANGER
Regulation 7.1a of the Management of Health and Safety at Work Regulations 1992 requires the
establishment of appropriate procedures to be followed in the event of serious and imminent
danger to persons at work.
1. Procedure for equipment which malfunctions and subsequently becomes dangerous
It is a requirement that all equipment currently being operated in the School must have both a
Safe Operating Procedure (SOP) and an Emergency Shutdown Procedure (ESP). In these
circumstances, but only if considered safe to do, the Emergency Shutdown Procedure should be
activated immediately. The fact that you are activating an ESP must be conveyed to all personnel
in the laboratory/room who should immediately vacate the area if their assistance is not required.
On completion of this procedure an assessment of the residual risks remaining should take place
to determine that it is safe to re-enter. If deemed unsafe to re-enter the procedure outlined below
should be followed.
In situations were it is considered unsafe to activate the ESP or re-enter the area after the ESP,
this should be conveyed immediately to a person who has H&S responsibility within this area,
ideally the Group Safety Adviser, Group Convenor or Laboratory Supervisor. After consultation
and consideration, if it is deemed necessary, the evacuation of an area, floor or building will be in
accordance with the Emergency Fire Procedures.
2. Procedure for equipment which poses an unacceptable risk
It is a requirement that all equipment currently being operated in the School must have both a
SOP and an Emergency Shutdown Procedure (ESP). In cases were no SOP is available the
equipment/process will be deemed to pose an unacceptable risk and therefore should be
immediately shutdown. In cases where an existing SOP is not being followed e.g. the removal of
guards, and it is deemed that an unacceptable risk has resulted, then the equipment/process
should be immediately shutdown. If the operator cannot be persuaded to stop, then this should
be conveyed immediately to a person who has H&S responsibility within this area, ideally the
Group Safety Adviser, Group Convenor or Laboratory Supervisor.
The Subject Group Safety Adviser must be informed of all cases that arise and are covered by the
above procedures, and they in turn must notify the School Safety Adviser.
The School Safety Adviser is Steve Ludlow who can be contacted on ext. 3406 or by email
[email protected].
ENTER DETAILS OF YOUR SUBJECT GROUP SAFETY ADVISER HERE:
Name
......…...........................................…
Location
…....................................................
Phone number
........................................................
.
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ACCIDENT AND INCIDENT REPORTING PROCEDURE
All accidents and incidents must be reported to Safety office using the new accident form http://www1.aston.ac.uk/staff/safety/accident-and-incident-reporting/. A copy of the completed
form should also be sent the School’s Safety Adviser.
GUIDANCE ON REPORTING PROCEDURES
1. Purpose
The purpose of this guidance is to provide a framework for the incident reporting and recording
procedure across the University. This procedural document should be viewed in conjunction with
the accident/incident reporting flowchart below
2. Definitions
Accident
An accident is an unplanned event, which has resulted in injury. This includes any
physical violence in connection with work.
Near Miss/Unsafe Condition
Where an incident occurs which does not result in an injury, but which had a high
potential for injury and/or where there was some damage or disruption.
Hazard
A hazard is something with the potential to cause harm
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3. Procedure
3.1 Responsibilities
3.1.1 Deans, Heads of Departments, Managers, School safety advisers and others with health
and safety responsibilities are responsible for:
Reviewing the incident in consultation with affected people to determine the appropriate
preventative actions
Informing the Safety Office on ext 4742/4743 immediately after a serious incident or near
miss/unsafe condition has occurred, or where it is likely that a member of staff will be
absent from work for more than 3 days following an accident.
3.1.2 Human Resources should notify the Safety Office of all 3 day work related absences
immediately after becoming aware of the incident/absence.
3.1.3 The Safety Office is responsible for notifying the Health and Safety Executive by
telephone or in writing of any notifiable incident or dangerous occurrence, and maintaining
the Accident Database
3.1.4 Security should notify the Safety Office of all serious incidents that occur after normal
office hours or during the weekends by following agreed escalation procedure.
GUIDANCE ON COMPLETING THE ACCIDENT/INCIDENT REPORT FORM
PART A INFORMATION ABOUT THE INCIDENT
SECTION 1: DETAILS OF THE INCIDENT
This section should be completed by an appropriate member of staff involved with the incident:
eg.
 person in charge of the activity or the area
 line manager
 first aider or security person
 nominated health and safety co coordinator
Describe how the incident occurred.
Provide a full account of what happened and how. This may include details such as:
 Injury, damage only, near miss/unsafe condition etc.,
 The date and time of the incident
 The exact location of the incident
 What the injured person was doing at the time
 What tools, equipment, material and fixtures were being used or handled
 Who else was involved?
 A description of any personal protective equipment or clothing used at the time
SECTION 2: DETAILS OF INJURED PERSON
Complete the section by providing details of:
 the full name and address of the injured person.
 the status of the injured person
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the injured persons employing department, if it’s a contractor the name of the employer.
the hours worked on day of injury
the type and position of the injury – specify which part of the body is injured
the type of injury sustained e.g. Face, leg (L), and arm (R) sprain, bruise, cut, fracture,
etc.,
SECTION 3: DETAILS OF WITNESS(ES)
Complete the section by providing a name, address and if possible, a telephone number, where
they can be contacted as part of the investigation process.
SECTION 4: DETAILS OF TREATMENT
Please give details of any treatment received, this will include:
 Where the person received first aid treatment, describe the treatment
 received.
 If the person went to hospital, please state if the person was taken to hospital
 immediately following the accident
 the mode of transport e.g. taxi, ambulance, by car, did they drive themselves
 If they went to their GP, was it later the same day, evening, next day etc.,
 Select the most appropriate statement of how the injury was managed
 Indicate the likely number of days the person will be absent from work as a result of the
injury, this includes the weekends.
The University has a statutory duty to report certain incidents under the requirements of the
Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 1995 (RIDDOR) to the
Health and Safety Executive. These include:
 Major injuries
 Accidents which result in the person being absent from work for more than
 three days
 Incidents which result in students or members of the public being taken to hospital for
treatment; and
 Dangerous occurrences
Serious accidents involving hospital treatment or more than 3 days off work should be referred to
the Safety Office as soon as possible on 0121 204 4742/4243
SECTION 5
The person completing Section A should sign and date the form, then submit the incident form to
the designated responsible in control of the area where the incidentoccurred.
PART B INFORMATION ABOUT THE INVESTIGATION
SECTION 6: SUMMARY OF FINDINGS OF INVESTIGATION
Each department must establish procedures to ensure that all accidents and incidents are
investigated by an appropriate person(s) within the Department. The investigation must not delay
the dispatch of the report form to the Safety Office. Additional information can always be
provided later as it becomes known. When the incident has been reported an investigation into
the cause of the must take place, the results of the investigation should be documented and
preventative measures put in place.
viii
An effective investigation should:
 Seek to establish both the immediate and the underlying causes of the incident, and
whether there is a need for any change to be made to prevent similar incidents occurring
in the future. Where appropriate specific mention should be made of any defects or
inadequacies of the equipment, substances or working conditions, safety procedures, and
whether the protective clothing/equipment was being used properly.
 Identify problem areas or particular hazards
 Identify corrective actions
 Provide management, supervisors, School/department health and safety advisers, health
and safety committees with data about the health and safety problems
 Identify training needs

The Safety Office will also investigate particular incidents and assist in the investigation
of all serious and dangerous occurrences in consultation with the area managers.
SECTION 7: ACTIONS TAKEN FOLLOWING THE INCIDENT
Give details of what action has been taken or required to prevent reoccurrence of the incident.
Any defects to a University building or the grounds must be reported to Estates and Facilities on
ext 4328. Specific measures of a long term nature should documented, and the date when
completed.
SECTION 8: PERSON COMPLETING PART B
Deans, Head of departments, are responsible for receiving the incident reports relating to matters
under their management and control and signing them to confirm that they are aware of the
incident and are reasonably sure that the information is correct, and are committed to the agreed
preventative action. On completion, send form to the Safety Office
SECTION 9: TYPE OF INCIDENT
This section is for the Safety Office use only. It allows the Safety Office to monitor and review
trends and assists in the production of reports to the Health and Committee, and in the production
of annual reports to the University Executive the Universities’ Safety and Health Association
(USHA).
SECTION 10: FOR USE BY HUMAN RESOURCES
This section is completed by Human Resources, and the form returned to the Safety Office.
ix
INTRODUCTION
This book contains some useful basic information on some of the more important aspects of
health and safety, which are particularly relevant to SEAS. It briefly describes the School’s and
University’s health and safety arrangements and emergency procedures. Sections concentrating
on specific hazards and sources of information follow this. It is intended to serve as a guide and
not as a comprehensive manual on health and safety.
Health and safety legislation places the onus to work safely firmly on each and every individual.
Every member of SEAS has, at all times, a duty to care for the Health and Safety of themselves,
and of anyone else who may be affected by their actions. Every member of the School must
observe this duty of care.
Responsibility cannot be delegated. As far as is reasonably practicable everyone must observe all
safety precautions. The provision or acquisition of information concerning hazards, before they
are encountered, and the development of sound practical technique are the main ways in which
safety standards can be improved.
SCHOOL HEALTH AND SAFETY POLICY
It is the policy of School to take all reasonably practicable measures to ensure a safe and healthy
working environment for staff, students, visitors and contractors, and to comply with current
Health and Safety legislation and the Health and Safety policy and Directives of the University.
SCHOOL HEALTH AND SAFETY OBJECTIVES
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The key objective is to protect the Health and Safety of employees, students, the public and
any others affected by our work, by providing and maintaining a safe workplace, safe systems
and practices.
To manage Health and Safety within the School with the same degree of determination and
competence that other key School issues are managed.
To manage Health and Safety within the School on the basis of the preparation and review of
annual School Health and Safety plans, that seek continual improvement, are founded on
Risk Assessments and have their progress monitored and reviewed at senior management
level.
To actively encourage and support consultation on Health and Safety issues.
To ensure that all its members receive appropriate Health and Safety information, instruction
and training, and are aware of any Health and Safety hazards and associated risks in their
workplace.
To endeavour to raise the profile of Health and Safety issues and the importance attached to
them, promote the idea of collective responsibility and in general, develop a positive Health
and Safety culture with a proactive approach.
To provide the resources and enabling structure necessary for its groups and members to
comply with current safety legislation.
To define the duties, roles and responsibilities of individual members and School committees
in terms of Health and Safety and monitor their performance.
1
ORGANISATION OF SEAS HEALTH AND SAFETY
Individuals with Specific Health and Safety Responsibilities
The Executive Dean, Professor Berry has overall responsibility for health and safety within the
School.
The School Safety Adviser, Steve Ludlow assists the Executive Dean on matters relating to
health and safety. He is responsible for coordinating health and safety activities and actions
throughout the School.
Heads of Group are responsible to the Executive Dean for health and safety within their Group
domain.
Group Safety Advisers assist their Head of GRoup on matters relating to health and safety. They
are responsible for coordinating health and safety activities and actions within their Subject
Group.
The duty of supervising postgraduates is delegated by the Executive Dean to the member of staff
directly responsible for the postgraduate.
The School has produced a comprehensive document entitled SEAS Health and Safety, Policy
and Objectives, Roles and Responsibilities (see appendix 1). This document defines the roles
and responsibilities of all individuals and committees within the School, and the School’s health
and safety management structure.
School Health and Safety Committees
The School has adopted a three-tier committee structure in-line with HSE thinking for organising
Health and Safety management. The three tiers reflect the roles of Policy Makers, Planners and
Implementers.
The School Health and Safety Executive Management Group represents the Policy Makers and is
responsible for the management of Health and Safety within the School. Its membership
comprises of the Executive Dean (Chairman), the seven Subject Group Heads, the Associate
Deans and the School Safety Adviser (Secretary).
The School Health and Safety Executive Group represents the Planners and is responsible for
producing a planned, systematic and co-ordinated approach to implementing the School’s Health
and Safety Policy and Objectives. Its membership comprises of the School Safety Adviser
(Chairman) and the Group Safety Advisers .
The third tier of the committee structure is designed to implement School Health and Safety
Policy at Subject Group level and also inform and consult with members on matters relating to
health and safety.
Formal Subject Group health and safety committees exist in CEAC, EE and EMS/MED for this
purpose and their meetings are chaired by the Group Safety Adviser with the School Safety
Adviser in attendance. These committees are comprised of representatives from all sections of
the Subject Group, including students. CS have effectively combined their Health and Safety
2
Committee with their Staff Student Consultative Committee by placing a standing item on the
latter’s agenda relating to Health and Safety matters and issues. Mathematics have adopted a
similar approach, by placing a standing item, relating to Health and Safety matters, on the agenda
of their Programme Committee. These arrangements reflect the general low risk nature of these
areas.
These committees all meet at least once a term. The full School health and safety structure is
given on the next page.
School Health and Safety Plan
.
The School’s key health and safety objective is To manage health and safety within the
School on the basis of the preparation and review of annual School health and safety plans,
that seek continual improvement, are founded on Risk Assessments and have their progress
monitored and reviewed at senior management level. To facilitate this an annual plan is
produced at the beginning of each calendar year.
This annual plan reviews progress made against the objectives and targets set out in the previous
year’s School health and safety plan. The format adopted for this plan is in line with the major
headings of the 1997 HSE Audit report for the University and contains sections relating to
Communications, Training and Competence, Co-operation, Planning and Implementation,
Monitoring and Reviewing and Auditing Performance.
Raising Health and Safety Issues
Health and safety concerns of a non-urgent nature should be raised at the Group’s Health and
Safety Committee or equivalent. This allows for a collective discussion to take place, decisions
taken and appropriate records to be made. The Group’s Safety Adviser should be consulted
directly in other cases or in matters considered to require urgent attention. In their absence these
matters can be raised with the Group Convenor, School Safety Adviser or even, in exceptional
circumstances, the Head of School.
Additionally, the School actively encourages its members to report all ‘hazards spotted and near
misses’ to the School Safety Adviser ([email protected]). These are logged and a formal
reply will be issued to the individual who has made the initial report.
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COUNCIL
EAS H&S Executive
Management Group
EAS Safety Advisory Group
Chemical Engineering
and Applied Chemistry
Head of Group
(Professor S Al-Malaika)
Computer Science
Head of Group
(Professor IT Nabney)
Mathematics
Head Of Group
(Professor D Saad)
SENATE
University H&S
Committee
University Executive
EAS Executive Dean
(Professor RF Berry)
EAS School Board
Engineering Systems
and Management
Head of Group
(Dr PD Hedges)
Electronic Engineering
Head of Group
(Dr DJ Webb)
CEAC Group
Members
Computer
Science Group
Members
Mathematics
Group
Members
Electronic
Engineering
Group
Members
CEAC Health
and Safety
Committee
Computer
Science
Health and
Safety Activity
Mathematics
H&S Activity
Electronic
Engineering
H&S
Committee
ESM Group
Members
Mechanical Engineering
and Design
Head of Group
(Professor GD Tansley)
Power Engineering
Head Of Group
(Dr M Booth)
MED Group
Members
Joint Engineering Systems and Management
& Mechanical Engineering and Design
H&S Committee
School of Engineering and Applied Science Health and Safety Structure
4
EAS School Centre
School Manager
(Andrea Chalk)
Power
Engineering
Group
Members
EAS School
Centre
Members
Power
Engineering
H&S Activity
EAS School
Centre H&S
Activity
UNIVERSITY CODES OF PRACTICE AND POLICES
Working in University buildings outside normal working hours
Normal working hours are currently defined as 0800-1800 hrs, Monday to Friday. 'Out of Hours'
refers to any time outside these normal working hours.
Legislation does not permit persons to work alone for certain activities, e.g. entering confined
spaces, working with unsecured ladders, erecting scaffolding, heavy lifting operations; and there
are many other work activities where consideration of potential risks to lone workers is vital,
particularly those involving the handling of hazardous chemicals and the use of certain
electrically powered tools and equipment.
As a general rule supervisors must ensure that any operation carrying a medium or high risk of
injury, is not undertaken by someone who does not have a colleague available to give appropriate
assistance.
A risk assessment must be carried out before any work is undertaken. The process of risk
categorisation into low, medium or high is fundamental to safe working out-of-hours.
Low Risk Work
This work may be undertaken by persons authorised to be present under the
terms of Local Rules for each Building, e.g. building rules may allow
cleaners to be present out of hours. Some buildings will allow members of
the public to attend lectures and other functions out of hours.
Medium Risk Work Medium Risk work may only be undertaken if there is at least one other
authorised person either in the same room or in an adjoining room within
earshot and, preferably, also within sight. (In special circumstances, e.g.
certain work by authorised Estates & Buildings personnel, workers may be
unaccompanied providing they are in direct radio communication with their
base station for the duration of the work.)
Medium Risk work may only be undertaken either - by persons authorised
by the Head of School or a Subject Group Convenor for the area concerned.
High Risk Work
These operations must never be undertaken outside normal working
hours unless:
 A special arrangement has been made to ensure the presence of a
first aider available either within the building or on radio call on
campus.
 The Head of School or the Subject Group Convenor for the area
concerned has approved the work.
 At no time during the work procedures are there less than two persons
present together in any high-risk location.
These are extracts from Aston University - Policy for working in University buildings outside
normal working hours.
Smoking Policy
Under the University’s smoking policy, rooms in all University premises except those otherwise
indicated in the full 'Policy' are designated as' NO SMOKING' areas. All School rooms are
classified as 'NO SMOKING' areas.
5
SAFE OPERATING PROCEDURES
Equipment in the School can only be operated if it has valid Safe Operating Procedure, which
must include an Emergency Shutdown Procedure. The only exceptions will be in cases which
are considered trivial or those in which a satisfactory reason for exemption has been proposed
and accepted.
RISK ASSESSMENT
The fundamental steps of risk assessment are
1.
Hazard Identification - Whatever method is used it needs to show that all hazards have
been considered. The two most common approaches to this are
a. a team of trained risk assessment personnel or
b. less competent individuals/teams working with the aid of a very comprehensive hazard
checklist to a prescriptive regime.
2.
Who the assessment is for and who may be harmed - Risk assessments reflect
competency, experience and training of individuals and groups and therefore the risk
ranking will reflect this. A number of risk assessments may therefore be required reflecting
that what may be a relatively high-ranking risk for one individual could be low for another.
3.
Evaluation of the risks - The risk related to a particular hazard is generally defined as a
function of the severity of the possible harm for the particular hazard and the probability
of occurrence of that harm. Numerically based systems rank individual hazards in terms of
risk and prioritise actions. Alternative systems are simply based on low, medium and high
rankings. These systems inevitably have very large steps between rankings and whilst this
does not lend itself well to prioritising remedial action, they do have the advantage of being
relatively simplistic.
4.
Identify and evaluate risk reduction options for each risk - All reasonable practical
steps must be taken to minimise the level of risk and the risk assessment should show this.
The following is a list of control measures in order of effectiveness:- Elimination,
Substitution by something less risky, Enclosure – enclose in a way that eliminates or
reduces risks, Guarding or segregation of people, Safe systems of work that reduces the
risk, Written procedures that are known and understood by those affected, Adequate
supervision, Identification of training needs, Information/instruction (signs/handouts) and
Personal protective equipment. In many cases a combination of these measures is
desirable.
5.
Record findings - An auditable record of the risk assessment process must be kept. It
must show
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the process by which all significant hazards have been identified
the details of all significant hazards have been identified
risk evaluations
actions taken or proposed to reduce risks including training and Personal Protective
Equipment (PPE) requirements
timescales for any proposed actions
estimates of residual risks
6
 any documentation that has been used in making this assessment
The records must show that the risk assessment has been carried out in a competent logical
manner and demonstrate suitable and sufficient steps have been taken.
6.
Set a strategy for reviewing and revising the assessment - Risk assessment strategies
should be revised regularly to ensure control measures are still adequately controlling the
risk. When significant changes are detected the risk assessment process is repeated.
School Strategy for Risk Assessment
SEAS has now adopted the following three-tier approach to risk assessment, which recognises
that the greater the risk the more rigorous the assessment procedure needs to be.
Level 1
Recognised Low Risk environments are evaluated using a simplistic approach of low,
medium and high severity and probability model. Generic assessment of some areas
may be possible. Any situations that subsequently are shown not to be low risk are
subjected to the next level of assessment.
Level 2
Risk assessments for non-low risk processes/equipment/areas that cannot be
adequately dealt with by the simplistic approach described above, are assessed using a
numerically based risk assessment system the School has developed. A
comprehensive hazard template has been developed against which risk data for
individual hazards is entered and action prioritised. Any
processes/equipment/areas/situations in which the risks have been classified as
substantial or intolerable by this system will be subjected to the next level of
assessment.
Level 3
Risks, which have been classified as substantial or intolerable will be subjected to a
further analysis by a University risk assessment team.
The different forms/workbooks to be used when assessing the risks at each level are available
from the School Safety Adviser. The following hazards have their own specific assessment
forms:- Chemical and Biological Hazards, Noise, Display Screen Equipment and Manual
Handling.
HEALTH AND SAFETY INFORMATION
Each Subject Group has its own health and safety information. SEAS has produced a number of
booklets relating to specific hazards. A brief synopsis of each follows in this handbook.
7
SUMMARY OF SAFETY RULES
TREAT SAFETY AS A MATTER OF PARAMOUNT IMPORTANCE.
Other instructions and suggestions are to be found in subsequent sections of this book and
specific hazard related School booklets. Everyone must observe the following rules:

No equipment can be operated unless it has valid Safe Operating Procedure, which must
include an Emergency Shutdown Procedure. The only exceptions are in cases which are
considered trivial or those in which a satisfactory reason for exemption has been proposed
and accepted. Ensure that a risk assessment has been made of the activity.

Learn the various emergency procedures.

Know the location of the nearest telephone, fire alarm, fire-fighting equipment, first aid
box and eye wash station. Ensure that all these appliances are maintained in a satisfactory
state.

Know the location of main control valves, stopcocks and switches.

Use all appropriate protective devices. Eye protection must be used in designated
laboratory areas at all times. Laboratory coats must also be worn when in laboratories.

Ensure that adequate information and instruction is available before any process or
handling procedure is attempted.

Ensure that adequate warnings are always displayed, and that warning notices, which no
longer apply, are removed.

Ensure that all equipment intended to run unattended for long periods, e.g. overnight, is
safely and securely assembled, and bears a notice showing the contents, condition and
emergency shutdown procedure.

Do not smoke, eat or drink in designated laboratory areas.

Do not wear laboratory coats in places where people eat or drink.

Do not leave fire-stop doors open.

Ensure that all hazardous materials are properly stored, and in the minimum quantities
consistent with the work being undertaken.

Report to the Subject Group Safety Adviser all accidents involving personal injury, and all
incidents which might have had serious consequences
Between certain limits (approx. 4.8% to 13.5% by volume of gas) gas and air form
flammable mixtures. If you suspect a gas leak you should extinguish all sources of
ignition. Do not switch on, or off, electrical apparatus/appliances. Inform the University
Security staff if the situation seems to be an emergency - telephone 222.
Doorways, gangways, corridors, and emergency exits are unobstructed.
Working areas are kept clean and uncluttered.
Waste chemicals are not allowed to accumulate.
If substances need to be stored in a fridge ensure that it is appropriate. In the case of
chemicals it must be sparkproof.
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8
CHEMICAL SAFETY
The hazard from a substance or preparation is defined as its intrinsic ability to do you harm. This
could include (and it’s not an exhaustive list) its toxicity, temperature, flammability, reactivity,
asphyxiant properties, and even its ability to harm the environment.
How much harm it will actually do is a complex function of its physical form, the route of entry
to the body, the quantity that was involved, its intrinsic properties and the response of the body.
Never forget that you are in more danger standing knee deep in a completely non-toxic dust than
you are if you have the most toxic substance in the world sealed in a robust container in your
pocket. Substances have other properties – they may be very reactive, so may present a
considerable hazard in taking part in runaway reactions or even explosions. They may be highly
flammable, and pose a threat in the form of fire.
Control of Substances Hazardous to Health (COSHH) Assessment
The COSHH Regulations provide a legal framework to protect people against health risks from
hazardous substances used at work.
Complying fully with COSHH involves:






assessing the risks to health arising from work with chemicals. Fundamentally, the risk
associated with a particular activity is function of the potential severity of injury of a
hazard and the probability of occurrence of that harm. COSHH risk assessments are
exactly the same, although the terminology may vary.
deciding what precautions are needed. No work should be undertaken which could expose
employees to hazardous substances, without first considering the risks and the necessary
precautions. Unless the risks have been judged correctly, it is unlikely that the right
precautions have been decided upon;
preventing or controlling exposure; If it is reasonably practicable, you must prevent
exposure by:
1. changing the process or activity so that the hazardous substance is not required or
generated; or
2. replacing it with a safer alternative, or
3. using it in a safer form, eg pellets instead of powder.
ensuring that control measures are used and maintained properly, and that any safety
procedures which have been laid down are followed;
monitoring exposure of workers to hazardous substances and carrying out appropriate
health surveillance, where the assessment has shown these are necessary or where
COSHH lays down specific requirements;
ensuring that employees are properly informed, trained and supervised.
The first step of the assessment is to determine the hazard category and exposure potential of the
substances and products of the process/reaction. The School has developed a COSHH
assessment procedure based on the The Royal Society of Chemistry model and this must be used
for your assessment and to record your findings.
Separate assessments will probably be needed for the different routes of entry into the body –
inhalation, skin absorption, ingestion etc. Suppliers of chemicals are legally obliged to provide
Material Safety Data Sheet (MSDS) to their customers. Most of the safety information you
need when completing assessments is there.
9
Chemical Agents Directive
The Chemical Agents Directive (CAD) requires employers to protect workers from certain health
and safety risks arising from chemical agents present in the workplace and from work activities
involving chemical agents. The term Chemical Agents is defined very widely and means any
natural or artificial substance or mixture of substances whether in solid, liquid or gas form. The
Directive is concerned with fire, explosion and health risks from chemical agents and applies to
all industrial and commercial sectors.
COSHH deals with the health risks and the recently introduced Dangerous Substance and
Explosive Atmosphere Regulations (DSEAR) deals with the safety risks classified under the
Chemicals (Hazard Information and Packaging for Supply) Regulations 2002 (S.I. 2002/1689)
(CHIP 3) as: explosive, oxidising, extremely flammable, highly flammable or flammable.
Similar to COSHH a risk assessment of the safety aspects is required.
DSEAR applies to any substance or preparation (mixture of substances) with the potential to
create a risk to persons from energetic (energy-releasing) events such as fires, explosions,
thermal runaway from exothermic reactions etc. Such substances, which are known in DSEAR
as dangerous substances, include: petrol, liquefied petroleum gas (LPG), paints, varnishes and
certain types of combustible and explosive dusts produced in, for example, machining and
sanding operations.
Reaction Categories
As part of the full risk assessment, consideration must also be given to the level of supervision
required when reactions are taking place. This must take account of the experimental
procedure(s) being used. An appropriate level of supervision should be assigned according to the
following simple scheme:A
B
C
D
This activity must be directly supervised
The advice and approval of your supervisor must be sought before the task started
The work involves risks requiring careful attention to the safety related aspects of it. The
worker has been trained in the task and has demonstrated competence
Tasks in this category carry no undue risks
Reactions involving substances which are carcinogens, mutagens or teratogens; pose risk of
serious eye damage; are pyrophoric, very highly toxic, or pose an explosion risk are by default
placed in category A.
Eye Protection
It is a legal requirement to wear eye protection in laboratories. Safety glasses must be worn as an
absolute minimum. Normal prescription glasses do not offer protection enough, and protective
over-goggles must be worn with them. Spectacles should be worn in preference to contact lenses,
which could trap chemicals between the lens and the eye. Soft lens in particular can also absorb
solvent vapour.
Lab. Coats
Lab. coats must be worn in laboratories. These must be regularly laundered and not worn outside
laboratory areas.
Further details of these assessment procedures and chemical safety in general can be found in the
School’s safety booklet Chemical Safety.
10
CRYOGENS
Although this is not an exhaustive list, you should be aware of the following key hazards
associated with using liquid nitrogen and liquid helium.
Asphyxiation – due to the displacement of air.
One of the main dangers associated with both liquid helium and liquid nitrogen is the risk of
asphyxiation, particularly when used or stored in poorly ventilated areas. This can be rapid, and
there are likely to be no obvious warning signs to the victim. There are no physical symptoms of
distress, and the function of the brain is seriously impaired in an oxygen deficient atmosphere,
without the person’s knowledge. It can take as little as two breaths in an oxygen deficient
atmosphere to cause unconsciousness, and death will occur within minutes. Below around 10%,
death or brain damage may be inevitable, even if the casualty is rescued and resuscitation is
attempted. The atmosphere normally contains approximately 21% oxygen by volume.
Atmospheres containing less than 18% oxygen are potentially dangerous, and entry into
atmospheres containing less than 20% oxygen is not recommended. Accident records show
that for every person who is overcome and dies in an atmosphere that does not support life,
statistically, more than one additional person dies, unsuccessfully attempting a rescue. It is
probable that a visible vapour cloud is significantly depleted in oxygen. Personnel should be
instructed never to enter a vapour cloud.
An assessment of the expected oxygen depletion should be made using the volume of room,
liquid nitrogen usage etc. to determine whether this likely to fall below 20%.
Consideration should be given to the installation of oxygen deficiency monitors and alarms in
areas where significant amounts of cryogens are being used or stored, particularly when poor
ventilation or confined spaces are involved.
Condensation of liquid oxygen
Since oxygen has a higher boiling point than nitrogen, it can condense into liquid nitrogen.
Fortunately it is a light blue colour, so if it has condensed in a significant quantity into an open
dewar of nitrogen it is obvious. Be aware that liquid oxygen is a serious fire hazard, and pure
oxygen can cause organic materials to ignite spontaneously or explode. Also, the liquid that
forms and runs off a nitrogen delivery tube from a dewar when you are discharging nitrogen is
rich in oxygen. Hence naked flames etc. are prohibited at nitrogen transfer points. Liquid that is
allowed to dribble onto clothing can take a very long time to disperse, and the individual is in
considerable danger while their clothing is rich in oxygen.
Condensation of water
Most of the time, the air is well laden with water vapour, and in consequence, wherever you
are using cryogens, you will have water vapour condensing out and often forming significant
ice burdens on pipes, etc. This can give rise to a risk of electrocution from ice forming, water
condensing and water dripping onto nearby electrical equipment.
Changes in material properties
We have all seen people smashing rubber hose, etc, when doing demonstrations with liquid
nitrogen. In polymers this is primarily due to the fact that cryogenic liquids take the material
well below its glass transition temperature, into a regime where it is brittle. It recovers if it is
11
warmed up – but it may break if it is disturbed while cold, or if it contains residual stresses.
Flooring may crack and cause a trip hazard. Carpeting appears to be just as vulnerable as lino.
Pneumatic tyres on vehicles that are exposed to liquid nitrogen may explode. Carbon steels (i.e.
not stainless) are body centered cubic, and also become dramatically more brittle at low
temperatures. They are not suitable for low temperature service. The drains cannot cope with
liquid nitrogen – the materials can be damaged - expensively. Even if the damage is not
immediately apparent, think what might happen when chemicals are disposed of down the drain
and where subsequently this leaked material will go. Damage to the insulation on electric
cables can produce an electrocution hazard.
Exposure to cold gases
Short exposures to cold gas vapour leads to discomfort in breathing whilst prolonged inhalation
can produce serious affects on the lungs and can trigger asthmatic attacks in susceptible
individuals.
Blockage of outlets from cryogenic containers
Liquid helium can readily cool air below its freezing point, which may lead to blockages in your
apparatus. It is possible that an explosion may result, because the helium will evaporate before
the blockage clears itself. Blockages can form with nitrogen as well, if ice forms in sufficient
quantity. Ice plugs are normally melted using hot air.
Burns
Liquefied gases, particularly when soaked into clothing, can produce burns that are similar to
heat burns. Unprotected skin may also stick to un-insulated items and flesh may be torn on
removal. More prolonged contact can cause the flesh to freeze. While frozen it will appear
yellow and waxy, and will probably not hurt, but when it thaws, it is likely to give rise to intense
pain. Such burns require immediate medical attention. Persistent, superficial contact with liquid
nitrogen can also give rise to chilblains – itchy, red, irritated patches of skin on the hands.
Reducing the Risks






Consider removing the problem altogether, which may be achieved by having less cryogen
in the space (e.g., not leaving the dewar in the room).
Ensure that cryogen from your apparatus is vented to a space that is large enough to accept
it without threatening the oxygen level.
Ensure the ventilation level is adequate to disperse the gas (but check on the status of the
ventilation system at night or at weekends).
Reduce the probability of accidental release by ensuring the stability of dewars,
maintaining the floor in good condition, ensuring personnel are trained, using labels and
diagrams, etc, to remind the forgetful.
Impose procedural control – such as prohibiting the transport of cryogens in a lift along
with personnel, prohibiting the transfer of cryogens at night, unless at least two people are
present.
Suitable gloves should be worn when handling very cold materials. Gloves for usage when
handling cryogens should be readily removable and special care should be taken to ensure
that the cryogens cannot enter the glove via. the cuff area.
For further information on the above and the assessment procedure consult the School’s safety
booklet The Use of Cryogens.
12
DISPLAY SCREEN EQUIPMENT (DSE)
Work involving DSE must comply with the requirements of the DSE Regs 1992. The University
has prepared Guidelines on the Regulations together with three questionnaires relating to DSE
use, the first of which is a self-assessment form, which helps determine whether a worker is a
‘user’ under the Regulations. This assessment is based upon a simple calculation involving the
type of work and method of working and the number of hours of DSE-related work undertaken
per week. If a worker is assessed as a ‘user’, then their workstation and ‘user interface’ are
assessed for compliance with the Regs using further questionnaires.
Under the Regulations ‘users’ of DSE are entitled to have their eyesight tested and to have their
workstations assessed to ensure that these comply with certain minimum standards. Eyesight
problems, although important (eye strain and associated headaches can be unpleasant), are not
causes for major concern, and radiation hazards (from monitors, etc.) have now been discounted
by many authorities as representing a significant risk.
However, it is musculo-skeletal disorders of the back and upper limbs, painful, severely
debilitating disorders such as RSI (repetitive strain injury) associated with the hands and wrists
which are considered to be very much the major issue. It is therefore important that proper
consideration be given to the design of the job, the layout of the workstation and the suitability of
the equipment that comprises the workstation and an assessment of these elements is made.
The primary requirements for a satisfactory workstation include the provision of a good quality
adjustable chair, a desk with a sufficiently large ‘knee-hole’ and a good-sized working surface especially depth, to accommodate a reasonably large-screened adjustable monitor and an
ergonomically satisfactory keyboard and mouse. The workstation should be placed so that
reflections on the monitor screen can be eliminated or reduced to acceptable levels.
Be aware that portable computers, laptops have comparatively poor ergonomics. The keyboards
are often less than full size and not properly angled. The LCD screens are an integral part of the
computer and have a more limited angle of view compared to a CRT monitor.
Display Screen Equipment User’s Daily Check List
When using your display for the first time today:

Raise or lower your seat until your forearms are horizontal. Make sure your wrists are
straight when your hands are on the keyboard.

Sit right back on your chair so that the back rest can support you.

Form a relaxed curve in your lower back and adjust your backrest to provide support
when in this position.

Use a footrest if your feet do not comfortably touch the floor.

Remove any obstacle under your desk that prevents you sitting in an upright position.

Position your copy stand close to your screen, e.g. the same height and viewing distance
and next to the display screen.

Set your display viewing distance to suit screen characters and copystand text size.

Check that you can reach your copy stand, without leaning forward, if you need to turn
pages regularly.

Adjust your screen and copystand angle to suit your sitting position.

If you are reading from hardcopy but do not use a copystand, offset your display slightly
so that you don't need to lean forward to read from the document.

Adjust the brightness control to suit the office lighting level.

Rest your arms and shoulders whenever your work routine allows.
13
When taking a work break or at the end of the day:

Exercise your legs and back by stretching and walking.

Try to avoid excessive wrist and arm activities, such as writing or knitting, during your
work break.

Try to rest your eyes by avoiding strenuous eye activities such as reading small print.

If you sit during your break adopt informal postures - but remember not to slouch.
When using your display after a 2-3 hour work session:

Check your workstation has not become disorganised, forcing you to sit in an awkward
position.

Adjust your brightness control if the light levels have altered since you started work.

Move your screen and document holder back* a little and adjust their angle to suit.
(* i.e. moving them away could help most (potentially long-sighted) users)

Lower window blinds if sunlight is causing glare.
Display Screen Equipment User’s General Check List
Are you sitting comfortably?

Try not to slouch - keep the curve in your lower back.

Adjust your backrest - support your lower back.

Sit right back in your chair - let the back rest support you.

Remove obstructions - don't let things prevent you from sitting upright at your desk.

Organise your workstation - place frequently used objects and equipment within easy
reach, and limit twisting movements of spine.

Place documents in holders where possible - don't lean forward to read hardcopy.

Break up your DSE work - use informal postures when not working.

Get some exercise - during breaks stretch your legs.
Are your arms and shoulders comfortable?

Adjust your seat height - make sure your forearms are horizontal.

Align hands with forearms - try to work with wrists straight.

Keep your wrist as straight as possible when using the mouse.

Use a footrest if your seat is too high & your feet don't comfortably reach the floor.

Adjust your screen angle to suit your sitting height.

Rest your arms whenever your routine allows.

Avoid arm and wrist activities, such as writing, during rest breaks
Can you read the screen?

Place the copystand close to your display

Adjust the copystand height - this should match display height.

Adjust your display height to minimise head/neck movement. Screen and angle of
viewing may be different for touch/copy typists (who look mainly at their copy) and nontouch (untrained!) typists (who also spend time looking at the keyboard!).

Vary your viewing distance occasionally - this could be done by moving the display
slightly after 2 to 3 hours of continuous working.

Sit sideways to windows - in particular, avoid windows behind you.

Use window blinds on sunny days

Clean your DSE screen regularly using approved cleaners only.

Adjust the brightness of display when light levels change

Rest your eyes during work breaks - don't read small print!
If you require a DSE assessment contact your Safety Adviser who will arrange this for you.
14
ELECTRICAL SAFETY
All electrical equipment and wiring must be in accordance with the ELECTRICITY AT
WORK REGULATIONS 1989. These are far-reaching and extensive and include many
additional items not previously contained in the IEEE regulations. NO EQUIPMENT
SHOULD BE IN USE IF IT DOES NOT MEET THE REGULATIONS.
All voltages are now included from 400KV to a 6 volt battery; the main criteria is to test whether
DANGER EXISTS (the risk of injury). All electrical equipment whenever manufactured,
purchased or installed, must conform even if its manufacture or installation pre-dates the
regulations.
No students are permitted to undertake any wiring of HV or mains equipment, unless this has
been previously authorised by an appropriate Electronics Technician. In these circumstances the
technician must check the work afterwards and before connection to any power supply. There
are special procedures, which must be followed when on live equipment. Under no
circumstances must students work on live equipment.
Do not interfere internally with any instruments. Only a competent person with the technical
knowledge, experience and necessary skill should undertake or carry out any wiring or repair
work. Remember, if it is not working, contact a person in authority. Accidents involving
electricity are quite often fatal. A high degree of protection is normally afforded by following
these established safety techniques:

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
Design and installation by competent personnel
Earthing of metal work which could become live under fault conditions
Mechanical protection of conductors / cables
Fuses or circuit breakers to protect equipment from excess current and to allow safe
isolation.
Residual current circuit breakers
Safe systems of work, which may include a permit to work system for certain
equipment/procedures and electrical lockout.
Routine maintenance of equipment.
Safety inspections of equipment, including regular visual inspections supplemented by
formal electrical testing at prescribed intervals.
Using electrical tools, which are appropriately insulated.
Ensuring flexible cables are firmly clamped at the ends, and damaged or frayed cables are
replaced.
Electric Shocks
The following advice is given by the St. John Ambulance,
The first priority with electric shock is to remove the source of current, DO NOT TOUCH THE CASUALTY
UNTIL THE ELECTRICITY SOURCE IS REMOVED. Switch it off at the supply (meter) if possible,
otherwise remove the plug or pull the cable from the casualty. If this is not possible push the casualty's
limb away from the source with a wooden pole whilst standing on an insulating material, i.e. phone book.
Always ensure your personal safety.
To receive a shock, you require two points of contact with a voltage difference between them,
such as live to earth or neutral. A current that flows from hand to hand, across the chest region,
presents great danger to heart function, though it is not in fact the worst; left hand to chest or foot
15
is potentially more serious but less likely to occur in a laboratory. As little as 100 mA of current
can produce heart fibrillation when the current is applied directly to the heart tissue. Current as
low as 50 mA can cause death.
Electrical Testing
The safe use of electricity and electrical equipment is controlled by the Electricity at Work
(EAW) Regulations 1989. They require that ‘precautions be taken against the risk of death and
injury. Under these Regulations, the University (via Estates) is responsible for checking all the
electrical services and wiring – from the sub-stations through to the electrical in each room. The
School makes arrangements to ensure that its own electrical equipment is both tested and
maintained, and that equipment on hire or loan is similarly safe.
The HSE recommend that user of any electrical equipment should visually inspect it on each
time before use. They should look critically for signs that the equipment is not in sound
condition, and particularly for the following:





Damage (apart from light scuffing) to the cable sheath – cuts, burns, splitting etc.
Damage to the plug – cracked case, bent pins etc.
Inadequate joints, including taped joints in the cable;
That the outer sheath of the cable is not effectively secured where it enters the plug or the
equipment. Obvious evidence of this would be if the coloured insulation of the internal
cable cores were showing;
That the equipment has been subjected to conditions for which it is not suitable, e.g. it is wet
or excessively contaminated;
If there is damage to the external equipment casing or there are some loose parts or screws;
Classification of Equipment.
Class I equipment is the most common type; its safety depends on the integrity of its one layer of
insulation and the earth bonding of its metalwork.
Class II equipment, often marked with a ‘double square’, depends on the provision of additional
insulation. Class IIA (All-insulated) has two layers (or equivalent) of insulation, one of which
covers or comprises the outer casing so that metalwork cannot be touched. In Class IIB
(Double-insulated) the equipment has all exposed metalwork separated from the conductors by
two layers of insulation so that the metalwork cannot become live. There is no earth connection
and the operator's safety depends on the integrity of the two layers of insulation.
Class III equipment operates on safety extra low voltage (SELV) i.e. at a voltage not exceeding
50V AC between conductors or to earth.
Residual Current Devices (RCD’s)
An RCD is a device, which detects faults in an electrical system and quickly switches off the
supply. Terms sometimes used to describe RCDs include Residual Current Circuit Breakers
(RCCBs) and Earth Leakage Circuit Breakers (ELCBs). RCDs are best used when they are built
into the mains switchboard or the socket-outlet, as this guarantees that the power supply cables
are continually protected. If this is not possible, a plug incorporating an RCD or a plug-in RCD
adaptor can be used. RCDs have a test button to check that their mechanism is functioning correctly. If an RCD
trips, it is a sign that there is a fault and the electrical system should be checked before it is used again
Consult the School’s safety booklet Electrical Safety for information about electrical safety.
16
FIRE SAFETY
The Fire Triangle
For a fire to start, three things are needed:- a source of ignition, fuel, and oxygen. If any one of
these is missing, a fire cannot start. Taking steps to avoid the three coming together will
therefore reduce the chances of a fire occurring.
FUEL
Flammable gases
Flammable liquids
Flammable solids
OXYGEN
Always present in the air
Additional sources from
oxidising substances
IGNITION SOURCE
Hot surfaces
Electrical equipment
Static electricity
Smoking/naked flames
Once a fire starts it can grow very quickly and spread from one source of fuel to another. As it
grows, the amount of heat it gives off will increase and this can cause other fuels to self-ignite.
The following paragraphs advise on how to identify potential ignition sources, the materials that
might fuel a fire and the oxygen supplies, which will help it to burn.
Identifying ignition sources






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


smokers' materials, eg cigarettes and
matches.
naked flames.
electrical, gas or oil-fired heaters
(fixed or portable)
hot processes (such as welding or
grinding work).
cooking.
engines or boilers.
machinery.
faulty or misused electrical equipment.




Identifying sources of fuel
17
lighting equipment, eg halogen lamps.
hot surfaces and obstruction of
equipment ventilation, e.g. office
equipment.
friction, eg from loose bearings or
drive belts.
static electricity.
metal impact (such as metal tools
striking each other).
chemical reaction
Anything that burns is fuel for a fire. Look for the things that will burn reasonably easily and are
in sufficient quantity to provide fuel for a fire or cause it to spread to another fuel source.
Some of the most common 'fuels' found in workplaces are:










flammable liquid based products such as
paints, varnish, thinners and adhesives;
flammable liquids and solvents
flammable chemicals;
wood, paper and card;
plastics, rubber and foam such as
polystyrene and polyurethane, eg the
foam used in upholstered furniture;
flammable gases such as liquefied
petroleum gas (LPG) and acetylene;
furniture, including fixtures and fittings;

textiles;
loose packaging material; and
waste materials, in particular finely
divided materials such as wood
shavings, offcuts, dust, paper and
textiles.
internal construction materials - areas of
hardboard, chipboard, blockboard walls
or ceilings, synthetic ceiling or wall
coverings, such as polystyrene tiles etc.
Identifying sources of oxygen
The main source of oxygen for a fire is in the air around us. In an enclosed building this is
provided by the ventilation system in use. This generally falls into one of two categories: natural
airflow through doors, windows and other openings; or mechanical air conditioning systems and
air handling systems. In many buildings there will be a combination of systems, which will be
capable of introducing/extracting air to and from the building. Additional sources of oxygen can
sometimes be found in materials used or stored in a workplace such as: some chemicals (oxidising materials),
 oxygen supplies from cylinder storage
which can provide a fire with additional
and piped systems, e.g. oxygen used in
oxygen and so assist it to burn. The
welding processes or laboratories
Material Safety Data Sheet (MSDS) will
give details of these properties.
Fire extinguishers
The type of extinguisher is identified by a colour code as indicated below. Water extinguishers
are coloured signal red. Other extinguishers will be predominantly signal red with the
manufacturers label, a band or circle covering at least 5% of the surface area of the extinguisher
of a second colour to indicate the contents of the extinguisher.
Type of Fire
Extinguisher
Colour
Recommended for
DO NOT USE ON
WATER
RED
Wood, paper, textile and solid
material fires
Liquid, electrical or metal fires
POWDER
RED with a
BLUE BAND
Liquid and electric fires
Metal fires
FOAM
RED with a
CREAM BAND
Liquid fires
Electrical and metal fires
CARBON
DIOXIDE
RED with a
BLACK BAND
Liquid and electric fires
Metal fires
For further information consult the School’s H&S booklet entitled Fire Safety or contact the
Fire Safety Adviser, Dave White Ext 4805
18
GAS CYLINDERS
Gases are often stored and supplied in high-pressure cylinders. Liquefied or dissolved gases are
also supplied in cylinders at lower pressures. Such cylinders are labelled and colour coded for
identification.
Guide to the safe use of gas cylinders

Always transport cylinders using a suitable trolley with the cylinder valve closed.

Check that the regulator being used is appropriate for the gas being used and cylinder
pressure.

Cylinders in use must be firmly supported in correctly designed racks or clamps, and fixed
in place independent of the piping or pressure regulator. Always store cylinders in safe and
secure manner. Notice that cylinders containing acetylene must be stored and used in an
upright position.

Never use grease or oil on valves, regulators or connections.

Report any faulty cylinders or regulators to the Subject Group Safety Adviser .

"Snifting", i.e. releasing a small amount of gas through the main cylinder valve to flush out
the seating, must be done with the cylinder upright and securely supported. It must never be
undertaken in a confined room or with toxic, inflammable or liquefied gases.

If a cylinder key is required it must be readily available, preferably attached to the rig.
Pressure regulator keys need not be available.

If corrosive and/or toxic gases are in use a warning chart should be displayed.

Copper piping should be used as far as possible for flammable gases but never for
acetylene.

Soft rubber tubing is prohibited for piping gases from cylinders.

Pipework intended for use with corrosive, toxic or flammable gases should, if possible, be
tested with air, nitrogen or carbon dioxide.

Ventilation should be adequate for normal running and to allow for possible mishaps.
Excess gas should not be vented into the room. There is a great danger of explosion with
flammables, and even non-toxics such as nitrogen and carbon dioxide may cause
drowsiness and possible asphyxiation.

All cylinders, especially hydrogen cylinders, should be screened from sources of heat
(including sunshine).

Hydrogen cylinder valves should be full-on or full-off, otherwise leakage may occur.

Special precautions should be taken as appropriate.
For additional information or help contact the University Gas Cylinder technicaian on Ext. 4772
or consult the School’s safety booklet Use of Gas Cylinders.
19
MANUAL HANDLING
All manual handling work needs to comply with the requirements set out in the Manual Handling
Operations Regulations 1992. Manual handling is defined in the Regulations as ‘the transporting
or supporting of a load (including lifting, putting down, pushing, pulling, carrying or moving
thereof) by hand or by bodily force’. Manual handling is a major cause of injury at work.
Statistics show that handling currently accounts for over one third of all reported accidents at
work. Over 73% of these handling accidents resulted in strains and sprains and almost 50% of
all handling accidents involved back injury.
The Approved Code of Practice, which accompanies the Regulations, contains much useful
advice on how to undertake an assessment of the risks associated with manual handling.
Appendix 1 of the Code of Practice is a detailed assessment guidelines filter. It helps to
concentrate the effort of assessment where it is needed by identifying handling operations that
warrant detailed examination by eliminating those activities that present only a trivial risk.
One of the best ways to approach an assessment is to consider first the following hierarchy of
possible measures:



Avoid manual handling operations wherever this is reasonably practicable.
Make an assessment of any hazardous manual handling operations that cannot be avoided.
Reduce, as far as practicable, the risk of injury from these operations.
The Regulations themselves don’t set specific requirements such as weight limits, but they do
give some guidance about weights to assist in assessing whether a task needs more attention.
These are the guidelines for lifting operations:
Note that these guidelines are for the average man and woman, in their prime and in good health.
They are based upon work activities involving relatively infrequent operations - say up to 30
operations per hour. The above guidance is also suitable for carrying operations where the load
is held against the body and carried for no further than 10 m without resting.
The Code of Practice also gives guidance on pushing and pulling operations. For this and
further advice on the assessment procedure, consult the School safety booklet Manual Handling.
20
MECHANICAL SAFETY
Workshops
Mechanical workshops can be very dangerous places especially for the untrained and
inexperienced. If you know that you are likely to need to use workshop facilities talk to the
workshop technicians well in advance. Some machine tools can be operated after only a small
amount of training, but others need a lot of training and experience to be operated safely.
General guidelines for workshop safety are given below:





Clothing Wear overalls in the workshops. They should have close-fitting cuffs, no loose
belts, be in good repair, and be worn buttoned or zipped up. Synthetic fibre materials should
not be used. Remove ties, scarves, rings, watches, bracelets, necklaces, etc., that are loose
and could possibly get caught in machinery. Wear safety shoes or strong leather type shoes
in the workshop. Canvas shoes, sandals and other flimsy footwear provide no protection
against injury and are not permitted. Wear the special protective clothing, such as aprons,
leggings, gloves, goggles, boots, provided in particular areas of the workshops such as
Welding and Heat Treatment. Wear eye protection both when operating a machine or
process that may produce flying particles, and when passing through an area where such
things are happening.
Skin Care Wear disposable gloves and/or barrier cream when handling potentially
hazardous or dirty materials. Be sure to wash thoroughly when you have finished. Use the
special-purpose hand cleansing creams provided.
Guards It is illegal, as well as dangerous, to operate an inadequately guarded machine.
Ensure that all guards, safety switches, etc., are correctly fitted and operational on any
machine or piece of equipment, before you operate it. Ask if you are not sure. Report
defective or missing guards and do not operate the machine until repairs have been effected.
Machine Tools Before starting, familiarise yourself with the method of quickly stopping
the machine that you are controlling. Ask for assistance if you are at all unsure how to
control the machine. Always give your full concentration to the job when operating a
machine. Stop the machine if you have to pause to talk to someone. Stop the machine if
you have to leave it unattended, even if it is only for a few seconds or a few metres distance.
Always wear eye protection when operating a machine. Make sure that any machine you
operate is in good order, properly adjusted and lubricated. If it appears to you not to be so,
report it to your Tutor and do not operate the machine. Stop the machine and isolate it
electrically before cleaning it. Remove machinings with a brush, stick or other suitable
implement. Never use your bare hands. Do not press buttons, turn handles or move levers
on any machine, other than the one you are operating.
Bench Work and Hand Tools Keep the floor area around the bench clear. Always ensure
that files have properly fitted handles of correct size. If you do not, the tang may pierce your
hand. Do not use tools which appear to be damaged. Use a copper, hide or lead hammer or a
soft drift, if you need to strike hard objects or machined surfaces. Hard-faced hammers on
hardened surfaces could produce dangerous flying fragments. Use spanners of the correct
size when tightening or slackening nuts and bolts. Ill fitting spanners may fly off and injure
you, as well as damaging the nut or bolt.
General Behaviour Always behave in a responsible manner. Pranks and horseplay can go
wrong and cause injury. Walk! If you run in a workshop you may trip and fall on
something, possibly causing injury. Make sure that there is someone else present when
working in a workshop. Do not work on your own; there will be no one to help you if you
sustain an injury. Remember that you must not operate any machine or piece of power
equipment in any section unless the tutor or technician in charge is present or their
21
permission has been obtained and you have received the necessary training to enable you to
carry out the work safely.
Work Equipment Regulations
'Work equipment’ covers any machinery, appliance, apparatus, tool or installation for use at work
and 'Use' relates to any activity associated with the work equipment, e.g. starting, stopping,
programming, servicing, cleaning The Provision and Use of Work Equipment Regulations 1998
requires the following:








Suitability Work equipment must be suitable for its intended purpose, and for the working
conditions in which it will be used.
Maintenance All work equipment must be maintained so that it is safe and does not put
people at risk. Maintenance should be performed by competent staff at regular intervals.
Where possible, preventative maintenance instructions should be used. These are usually
based on the equipment manufacturer's recommendations and if followed will help to
reduce the risk of failure whilst the equipment is in use. The PUWER guidance leaflet
recommends that maintenance logs be kept.
Inspection In certain circumstances, inspection should be carried out to ensure that work
equipment is, and continues to be, safe for use. Any inspection should be performed by
competent staff and a record kept.
Specific Risks Equipment, which poses specific health and safety risks, should only be
operated by suitably trained employees. As well as this, the maintenance and repair of such
equipment should also be restricted to those who are competent and have been specifically
designated to perform the work.
Information, Instructions and Training Employers are required to provide adequate
health and safety information, instruction, and training for every employee. Written
instruction on the use of work equipment and health and safety issues should be provided
where necessary.
Dangerous Parts of Machinery Employers must take measures to restrict access to
dangerous parts of machinery. There must be effective measures to prevent access to
dangerous parts of machinery or stop their movement before an employee enters the
'danger zone' (defined as any area of risk under health and safety law). The Regulations
require a strict hierarchy of measures to be taken, e.g. if the provision of fixed guards does
not fully reduce the risks then protection devices should be considered. They advise that
any protection devices should be suitable for their purpose and maintained as such, be of
good construction, and in good repair. Employees should be appropriately informed,
instructed and trained, and if necessary, supervised whilst using dangerous machinery.
Protection Against Specified Hazards This regulation outlines controls for protection
against the following hazard areas: Falling or ejected articles or substances, Component
rupture or disintegration of work equipment parts, Unintended or premature discharges of
gas, dust, or other substances, Over-heating and catching fire, and Unintended explosions.
Protective measures should be implemented including measures to minimise hazardous
effects and prevent such problems occurring.
Controls Where appropriate, work equipment must be fitted with operating controls
(which alter speed and pressure), stop controls and emergency stop controls. All controls
must be easily accessible and clearly visible.
Stability Some equipment will need to be stabilised by clamping or otherwise where
necessary for purposes of health and safety. Machines which are usually in a fixed
position, should be bolted down where possible.
For further information about mechanical, machinery and workshop safety see the section of this
booklet entitled Code of Practice for Mechanical Workshop Safety (page 32).
22
NOISE
Because the human ear is not equally sensitive to sounds at all frequencies, occupational noise is
measured in a way that stimulates the response of a healthy human ear. This is generally referred
to as decibels with ‘A’ weighting, written dB(A). It is not often appreciated that this decibel
scale is logarithmic and with every increase of 3 dB(A) the sound pressure is doubled. Thus 85
dB(A) is twice as loud as 82 dB(A) and four times louder than 79 dB(A).
Loud noise can cause :
permanent damage to hearing. (noise induced hearing loss is irreversible.)

your hearing to become less sensitive.

tinnitus (permanent ringing in the ears).

breakdown of safe and effective communications

fatigue and tiredness.
Temporary, partial loss of hearing, which may persist for several hours, can be caused by brief
exposure to high noise levels. Such exposure if repeated or prolonged may lead to permanent
hearing damage. It is one of the most serious and widespread industrial diseases.
The Noise at Work Regulations sets 85 dB(A) as the noise level at which employers are
specifically required to act on noise. Noise surveys must be carried out and precautions
recommended for those areas where daily average noise exposure exceeds 85 dB(A).
If you are planning, or starting, any new ‘noisy’ activity contact the School Safety Adviser so
that it can be assessed.
"Nuisance" noise which might disturb concentration, e.g. from traffic or a noisy process next
door, is not in the range covered by the Regulations. As a rough guide, an assessment of noise
exposure is needed wherever people have to shout or have difficulty in being heard clearly by
someone about 2 metres away, or if they find it difficult to talk to each other. This 2m distance
relates to about 85 dB (A) and a 1m distance relates to about 90 dB(A).
The main provisions of the Regulations are as follows:








The employer is under a general duty to reduce the risk of occupational hearing damage to
the lowest level reasonably practicable.
Where daily personal noise exposure is likely to be at 85 dB(A) or above, noise level
assessments must be made.
Where employees are exposed to 85 to 90 dB(A) ear protectors must be provided although
there is no statutory requirement to wear them.
Where exposure is above 90 dB(A) the employer is obliged to reduce noise so far as
reasonably practicable, by means other than ear defenders.
So long as exposure is above 90 dB(A) the employer must enforce the use of ear protectors
and employees must wear them.
"Ear protection zones" where exposure is above 90 dB(A) must be clearly marked.
Information must be provided to workers about risks to their hearing.
The employer must ensure, in so far as is practicable, that all equipment provided as part of
complying with these Regs. is correctly used and maintained.
N.B. When the Physical Agents (Noise) Directive is implemented in early 2006 it will tighten
the legal requirements by lowering the exposure action values by 5dB to 80 and 85dB(A).
For further information and guidance, consult the School’s H&S booklet Noise. Contact the
School Safety Adviser if you think a noise assessment is required.
23
PERSONAL PROTECTIVE EQUIPMENT (PPE)
The main requirement of the PPE at Work Regulations 1992 is that personal protective
equipment is to be supplied and used at work wherever there are risks to health and safety that
cannot be adequately controlled in other ways.
PPE is defined in the Regulations as 'all equipment (including clothing affording protection
against the weather) which is intended to be worn or held by a person at work and which protects
them against one or more risks to his health or safety', e.g. safety helmets, gloves, eye protection,
high-visibility clothing, safety footwear and safety harnesses. Waterproof, weatherproof or
insulated clothing is subject to the Regulations only if its use is necessary to protect employees
against adverse climatic conditions that could otherwise adversely effect their health or safety.
In general, because the effectiveness of PPE can be easily compromised, e.g. by not being worn
properly, it should always be considered as the last resort and used only where other precautions
cannot adequately reduce the risk of injury. Where PPE is the only effective means of
controlling the risks of injury or ill health and then employers must ensure that it is available for
use at work - free of charge.
Also, in many laboratory and workshop areas minimum PPE levels have been set to reinforce
control measures and working practices. In chemical labs. for example there is a minimum
requirement to wear both safety spectacles and a lab. coat.
HAZARDS
CHOICES
EARS
Noise - Assessments are made under the
Noise at Work Regulations 1989
Earplugs; Ear defenders.
EYES
Chemical or metal splash; Dust; Projectiles:
Gas and Vapours: Radiation
Spectacles: Goggles; Face screens
HEAD AND
NECK
Impact from falling or flying objects: Risk of
head bumping; Hair entanglement
Helmets; Bump caps; Hats; Caps;
Sou’westers and cape hoods; Skull-caps.
BREATHING
Dust; Vapour; Gas; Oxygen deficient
atmospheres
Disposable filtering face piece or respirator;
Half/full face respirator; Air-fed helmets;
Breathing apparatus.
Temperature extremes; Adverse weather;
Conventional or disposable overalls; Boiler
Chemical or metal splash; Spray from
PROTECTING
suits; Donkey jackets; Specialist protective
pressure leaks or spray guns; Impact or
clothing e.g. chain-mail aprons; High
THE BODY
penetration; Contaminated dust; Excessive
visibility clothing
wear or entanglement of own clothing.
HANDS AND
ARMS
FEET AND
LEGS
Abrasion; Temperature extremes; Cuts and
punctures; Impact; Chemicals; Electric
Gloves; Gauntlets; Mitts; Wristcuffs; Armlets
shock; Skin infection; Disease or
contamination; Vibration.
Wet; Electrostatic build-up; Slipping; Cuts
and punctures; Falling objects; Metal and
chemical splash; Abrasion.
Safety boots and shoes with steel toe caps
(and steel mid sole); Gaiters; Leggings;
Spats.
The above table lists the parts of the body you should consider when making a PPE assessment,
the associated hazard categories and the protection choices. For further information consult the
School booklet Personal Protective Equipment.
24
PRESSURE SYSTEMS
Pressure Systems Safety Regulations 2000
In order to accommodate the implementation of the European Pressure Equipment Directive
(PED), adopted in May 1997, the Pressure Systems and Transportable Gas Containers
Regulations 1989, have been revoked and replaced with new consolidated regulations, the
Pressure Systems Safety Regulations 2000.
The aim of PSSR is to prevent serious injury from the hazard of stored energy as a result of the
failure of a pressure system or one of its component parts. The Regulations are concerned with
steam at any pressure, gases which exert a pressure in excess of 0.5 bar above atmospheric
pressure and fluids which may be mixtures of liquids, gases and vapours where the gas or vapour
phase may exert a pressure in excess of 0.5 bar above atmospheric pressure.
PSSR is concerned with the risks created by a release of stored energy through system failure.
With the exception of the scalding effects of steam, the Regulations do not consider the
hazardous properties of the contents released following system failure. The properties of the
stored contents are of concern only to the extent that they may be liable to accelerate wear and
cause a more rapid deterioration in the condition of the system, so leading to an increased risk of
failure. The risk from steam includes not only any possible deterioration in the condition of the
system, which could increase the risk of failure, but also its scalding effect in the event of
release. PSSR does not deal with all the hazards arising from the operation of such a system,
even though the contents may be highly toxic. These aspects are all subject to separate
legislative requirements and will need considering, along with other aspects when deciding on
the level of precautions required.
Pressure Equipment Regulations 2002 (PER)
PER contain requirements for the design, manufacture and conformity assessment of certain
types of pressure equipment with a pressure greater than 0.5 bar gauge. PER covers the supply
and putting into service of equipment that would also form whole or part of a pressure system,
that falls within the scope of PSSR.
PER divides pressure equipment into four major categories on the basis of two fundamental
hazards:

The degree of danger from failure of the equipment (expressed by the product of the
pressure of the fluid and the volume of the equipment or DN value for piping products).

The degree of danger from this release of the fluid contained (based on classifications
adopted in the directives on dangerous substances).
The regulations define three types of systems
(a)
(b)
(c)
a system comprising a pressure vessel, its associated pipe-work and protective devices.
pipe-work with its protective devices to which a transportable pressure receptacle is, or is
intended to be, connected.
a pipeline with its protective devices.
and these systems in turn are further sub-divided into minor, intermediate or major.
For further information and advice consult the School’s safety booklet entitled Pressure Systems.
25
RADIATION
Ionising Radiation
Radiation that produces ionisation in matter e.g. α particles, γ rays, X rays and neutrons. When
these radiations pass through the body tissue, they have sufficient energy to damage DNA.
To comply with the necessary registration procedures the Radiological Protection Officer (RPO)
MUST be consulted before commencing work involving any of these techniques. The member of
staff responsible for experimental work involving these techniques must make the necessary
arrangements for undergraduates. A booklet entitled "Recommendations and Notes for the
Guidance of Departments Working with Radioactive Substances and Ionising Radiations", is
available from the University Safety Adviser (USA).
In the event of an accident involving radioactive contamination or exposure to X-rays or Laser
beams, the USA (telephone 4513) or the RPO (4776) must be contacted immediately.
Non-Ionising Radiations
Radiation that does not produce ionisation in matter. Examples are ultraviolet radiation, light,
infrared radiation and radiofrequency radiation. When these radiations pass through the tissues of
the body they do not have sufficient energy to damage DNA directly. For advice on radiation
consult the School’s Safety booklet entitled ‘Radiation Safety’
Radiation Protection Supervisor (RPS) Any School, or a constituent subject area, which uses
ionising radiations must have an RPS, who will be appointed in writing by the University. The
RPS supervises work activities in the area(s) specified in the Local Rules, and assists in ensuring
compliance with the arrangements made by the University in the Local Rules and other
university guidance on radiological safety.
Local Radiation Assistant (LRA) LRA are appointed to provide day-to-day assistance to the
RPS. An LRA will be an employee involved in ionising radiation work in a specified work area.
Lasers
Lasers produce electromagnetic radiation at wavelengths extending from 100 nm in the ultraviolet, through the visible (400-700 nm), and the near infrared (700-1400 nm), to the far infrared
(1400 nm – 1 mm). Thus, the light emitted can be either visible or invisible. Lasers can be
operated in a number of different modes. Some lasers produce a continuous output and are
known as continuous wave or CW lasers. The power outputs of CW lasers are usually expressed
in terms of watts (W). Others operate in a pulsed mode producing short bursts of radiation. The
power of the laser output can vary from less than 1mW to many watts in some CW devices. The
energy output of pulsed lasers is generally expressed in joules (J) per pulse.
Because of the wide ranges possible for the wavelength, energy content and pulse characteristics
of laser beams, the hazards arising from their use varies widely. It is impossible to regard lasers
as a single group to which common safety limits can apply. A system of laser classification is
used to indicate the level of laser beam hazard and maximum Accessible Emission Levels
(AELs) have been determined for each class of laser. The previous classification system, which
was based on five classes (1, 2, 3A, 3B & 4), has been replaced with a new system of seven
classes (1, 1M, 2, 2M, 3R, 3B & 4) and these are described below.
26
Class 1
Lasers that are safe under reasonably foreseeable conditions of operation, either
because of the inherently low emission of the laser itself, or because of its
engineering design such that it is totally enclosed and human access to higher levels
is not possible under normal operation. NB If access panels of a totally enclosed
system are removed for servicing etc then the laser product is no longer Class 1 and
the precautions applicable to the embedded laser must be applied until the panels are
replaced.
Class 1M Laser products emitting in the wavelength range 302.5 nm to 4000 nm, whose total
output is in excess of that normally permitted for Class 1 laser products but because
of their diverging beams or very low power density do not pose a hazard in normal
use and comply with the measurement conditions for a Class 1M product. However
they may be hazardous to the eyes under certain conditions if gathering optics are
used with them, i.e. a) With a diverging beam if optics are placed within 100mm of
the source to concentrate/collimate the beam. or b) With a large diameter collimated
beam viewed with binoculars or a telescope.
Class 2: Lasers that only emit visible radiation in the wavelength range from 400 nm to 700
nm and whose output is less than the appropriate AEL. They are safe for accidental
viewing as eye protection is afforded by aversion responses, including the blink
reflex. This reaction may be expected to provide adequate protection under
reasonably foreseeable conditions of operation including the use of optical
instruments for intrabeam viewing.
Class 2M: Laser products that only emit visible radiation in the wavelength range 400 nm to 700
nm, whose total output is in excess of that normally permitted for Class 2 laser
products but because of their diverging beams or very low power density are safe for
accidental viewing during normal use and comply with the measurement conditions
for a Class 2M product. However they may be hazardous to the eyes under certain
conditions if gathering optics are used with them, i.e. a) With a diverging beam if
optics are placed within 100mm of the source to concentrate/collimate the beam. or
b) With a large diameter collimated beam viewed with binoculars or a telescope.
Class 3R: Lasers that emit in the wavelength range from 302.5 nm to 1 mm where direct
intrabeam viewing is potentially hazardous but the risk is lower than for Class 3B
lasers, and fewer manufacturing requirements and control measures for the user
apply. The AEL is restricted to no more than five times the AEL of Class 2 for
visible wavelengths and no more than five times the AEL of Class 1 for other
wavelengths.
Class 3B: Lasers that are normally hazardous when direct intrabeam exposure occurs (i.e.
within the Nominal Ocular Hazard Distance, which is the distance within which the
beam irradiance or radiant exposure will exceed the appropriate MPE). Viewing
diffuse reflections is normally safe. Output levels must be less than the appropriate
AELs for Class 3B devices.
Class 4: High power lasers that exceed the AELs for Class 3B products that are also capable
of producing hazardous diffuse reflections. They may cause skin injuries, could also
constitute a fire hazard and could cause hazardous fumes to be produced as well as
being a hazard to the eyes. Their use requires extreme caution.
Laser Protection Supervisor (LPS) Any School, or a constituent subject area, using lasers (Class
3b and above) must have one or more LPS, who will be appointed in writing by the University.
The LPS supervises work activities in the area(s) specified in the Local Rules, and assists in
ensuring compliance with the arrangements made by the University.
Local Laser Assistant (LLA) LLA provide day-to-day assistance to the LPS. An LLA will be an
employee involved in non-ionising radiation work in a specified work area.
27
SLIPS, TRIPS AND FALLS
Over a third of all major injuries reported each year are caused as the result of a slip or trip. Slips
are 6 times more frequent than trips. The HSE recommend adopting the following approach.
1.
2.
3.
4.
5.
Look for slip and trip hazards around the workplace, such as uneven floors, trailing
cables, areas that are prone to spillages.
Decide who might be harmed and how. Who comes into the workplace and are they at
risk?
Consider the risks. Are the precautions already in place sufficient to deal with the risks?
Record the findings.
Regularly review the findings.
Good working practice
Ensure that conditions are right from the start. Choose only suitable floor surfaces and ensure
that lighting levels are adequate. Cleaning methods and equipment must be suitable for the type
of surface being treated.
Carry out all necessary maintenance work, including inspection, testing, adjustment and cleaning
at regular intervals, taking care to ensure that additional slip and trip hazards are not created.
Lighting should enable people to see obstructions, potentially slippery areas etc. Floors should
be checked for loose finishes, holes and cracks, worn rugs and mats etc. Obstructions and
objects left lying around can easily go unnoticed and cause a trip. Try to keep work areas tidy
and if obstructions can’t be removed, warn people using signs or barriers. Correct footwear can
play an important part in preventing slips and trips.
Reducing the risk of slipping and tripping
HAZARD
SUGGESTED ACTION
Clean spills up immediately. If the liquid is greasy ensure a suitable cleaning
Spillage of wet or dry agent is used. After cleaning the floor may be wet for some time. Use
substances
appropriate signs to tell people the floor is still wet and arrange an alternative
bypass route.
Position cables to avoid cables crossing pedestrian routes. Use cable covers to
Trailing cables
securely fix to surfaces. Restrict access to prevent contact.
Rubbish e.g. plastic
bags
Flooring
Slippery surfaces
Keep areas clear. Remove rubbish and do not allow it to build up.
Ensure that all flooring e.g. carpets, rugs, mats and lino, is securely fixed and
does not have curling edges. Replace worn floor covering.
Assess the cause and treat accordingly e.g. treat chemically, devise an
appropriate cleaning method.
Change from wet to dry Use suitable footwear. Warn of risks using signs. Locate doormats where
floor surface.
changes are likely.
Poor lighting.
Changes of level.
Slopes
Unsuitable footwear
Improve lighting levels and placement of light fittings to ensure more even
lighting of all floor areas.
Improve lighting levels. Add apparent tread nosings.
Improve visibility. Provide handrails. Use floor markings.
Ensure that the correct type of footwear is used. Particular attention should be
paid to the type of sole.
28
VACUUM SYSTEMS
Glass systems are particularly vulnerable and should be protected against the risk of implosion
should mechanical defects develop while the system is under vacuum. Glassware under vacuum
must have a protective cover, e.g. cling-film to prevent flying glass. Thin-walled or nonspherical glass flasks should not be evacuated. Also, all modifications and repairs to glass
vacuum systems can only be undertaken by an experienced glassblower.
Gas leaks from the chamber into the lab. may result depending on the gases used, may result in
explosion, toxic effects or asphyxiation. Air leaks into the chamber, may produce potentially
explosive or toxic mixtures. Ensure systems are leak free before introduction of process gases
and ensure that exhaust systems are working effectively and are properly ventilated.
Minimise mechanical shock by turning taps slowly when equalising a large pressure differential,
especially if a large bulb volume is involved. Arrangements must be made to ensure that
chemical vapours condensed out and their ingress into the pumping system is prevented.
Liquid nitrogen traps on vacuum systems must only be filled after pumping down (to prevent
O2 condensation). Air must not be readmitted until the liquid N 2 reservoir has been removed.
Vacuum Pumps
All oil pumps must be used properly if they are to function efficiently. This efficency is reduced
if the oil becomes thick (due to dissolved chemicals) and the metal surfaces become pitted (due
to exposure to corrosive materials). You should be trained in the use of vacuum pumps but it is
most important to make certain that the vacuum system in the apparatus is discharged (i.e. the
equipment is returned to atmospheric pressure) before the pump is switched off. This prevents
suckback of oil from the pump into the system. Diffusion pumps are more complex in operation
and an experienced user must be consulted before you attempt any usage.
Consult the School’s H&S booklet Vacuum Systems for further information.
WORKING AT HEIGHTS
Falls from height are one of the biggest killers of personnel in the workplace. Work at height
should ideally be carried from a platform with suitable edge protection. Occasionally this may
not be possible and a ladder may have to be used. However, ladders are best used as a means of
getting to a workplace and should only be used as a workplace for light work of short duration. It
is tempting to use a ladder for all types of work but you should always consider working from a
platform first, for example, a properly erected mobile scaffold tower or a mobile elevated
working platform.
Stepladders
 Do not use the top platform of the stepladder unless it is designed with special handholds.
 Ensure stepladders are stable and positioned on level ground and used in accordance with the
manufacturer’s instructions.
 Do not walk down facing the wrong way.
 Do not use stepladders leaning against a wall and do not overreach.
 Be extremely careful if working off the short axis of a stepladder; this is not advised, since
stepladders have little stability along this axis - work off the long axis whenever possible.
29
Ladders
 Ladders should be in good condition and examined regularly for defects.
 They should be securely fixed so they cannot slip, usually by tying them at the top. If this is
not practicable then a person must be stationed at the foot of the ladder when in use to
prevent it slipping, but this concession can only be applied when the ladder is less than 20
feet long.
 The ladder should be angled to minimise the risk of slipping outwards. As a rule of thumb it
should be set ‘one out for every four up’ or 75 degrees.
 Access ladders should extend about 1m above the work platform, to provide a handhold for
people getting on and off.
 Do not overreach. If you are working from a ladder, make sure it is long enough and
positioned to reach work safely.
 Do not climb or work off a ladder unless you can hold it safely.
 When in use ladders should not obstruct escape routes.
Scaffold Towers
 It is essential that users ensure that scaffold towers are erected, used and dismantled safely.
Accidents involving tower scaffolds are mainly caused by poor standards of erection or
misuse.
 A competent person must erect the scaffold in a manner fully compliant with the
manufacturer’s instructions. Also, any alterations or dismantling must be performed by a
competent person.
 When a tower is left incomplete a warning notice ‘TOWER INCOMPLETE : DO NOT
USE’ should be clearly displayed.
 Care should be taken to ensure loads are evenly distributed and do not exceed those set by
the manufacturer. Never climb on towers from the outside.
 The tower cannot be used until appropriate working platforms, toe boards, guard rails and
stabilisers/outriggers have been fitted. Never use general scaffold boards with a mobile
structure. Only use the correct size pre-formed platform supplied by the manufacture.
 Each time before using ensure the tower is vertical and the wheel brakes are on.
 When moving a tower check the following:a. check that there are no power lines or other overhead obstructions.
b. check that the ground is level and firm.
c. push or pull on the base – never use powered vehicles.
d. never move it while there are people or materials on the upper platforms.
 Traditional scaffold can only be erected by a qualified scaffolding contractor.
Falling objects
Care should be taken to prevent objects falling onto people. This may involve the following: Providing barriers, such as toe boards or mesh guards, to prevent items falling off the edge
of a structure.
 Securing objects to the structure.
 Making sure that there are no loose objects and that all tools are secured.
 Creating an exclusion zone beneath areas where work is taking place and where necessary
providing personnel with safety helmets.
 Clearly marking areas where work is being undertaken above with safety signs warning
workers of the dangers.
 Using safety nets.
For further information consult the School’s H&S booklet Working Safely at Height.
30
WORK ENVIRONMENT
The Workplace (Health, Safety and Welfare) Regulations 1992 require that workplaces meet
certain basic standards.
Ventilation
Workplaces need to be adequately ventilated. Fresh, clean air should be drawn from a source
outside the workplace, uncontaminated by discharges from flues, chimneys or other process
outlets, and be circulated through workrooms.
Ventilation should also remove and dilute warm, humid air and provide air movement, which
gives a sense of freshness without causing draught. If the workplace contains process or
heating equipment or other sources of dust, fumes or vapours, more fresh air will be needed
to provide adequate ventilation.
Windows or other openings may provide sufficient ventilation but, where necessary,
mechanical ventilation systems should be provided and regularly maintained.
Temperatures in indoor workplaces
Comfort depends on air temperature, radiant heat, air movement and humidity. Individual
personal preference makes it difficult to specify a thermal environment that satisfies
everyone. For workplaces where the activity is mainly sedentary, for example offices, the
temperature should normally be at least 16 degrees Celsius. If the work involves physical
effort it should be at least 13 degrees Celsius (unless other laws require a lower temperature).
Work in hot or cold environments
The risk to the health of workers increases as conditions move further away from those
generally accepted as comfortable. Risk of heat stress arises, for example, from working in
high air temperatures, exposure to high thermal radiation or high levels of humidity, such as
those found in foundries, glass works and laundries. Cold stress may arise, for example,
from working in cold stores, food preparation areas and in the open during winter.
Assessments of the risk to worker’s health, from working in either a hot or cold environment,
needs to consider two sets of factors – personal and environmental. Personal factors include
body activity, the amount and type of clothing, and duration of exposure. Environmental
factors include ambient temperature, and radiant heat: and if the work is outside, sunlight,
wind velocity and the presence of rain or snow.
Lighting
Lighting should be sufficient to enable people to work and move about safely. If necessary,
local lighting should be provided at individual workstations, and at places of particular risk.
Lighting and light fittings should not create any hazard. Automatic emergency lighting,
powered by an independent source, should be provided where sudden loss of light would
create risk.
For further information or guidance consult the Schools safety booklet Workplace
Environment.
31
Code of Practice for
Mechanical Workshop Safety
Introduction
Mechanical workshops can be very dangerous places especially for the untrained and
inexperienced. They contain machinery which can kill or maim in a split second if it
is not correctly guarded and operated. If you know that you are likely to need to use
workshop facilities talk to the workshop technicians well in advance. Some
machine tools can be operated after only a small amount of training, but others need a
lot of training and experience to be operated safely.
Most working accidents could have been prevented by proper preparation or better
working methods. Yet accidents are still happening - because guards are not
correctly placed to prevent inadvertent contact with dangerous parts; because work
pieces are not clamped and lacerate the operator's hands; because swarf gets into the
eye of someone who should have been wearing safety spectacles; or simply because
people slip or trip over material left on the floor.
The purpose of this Code is to eliminate or reduce accidents, by providing guidance
to all those who use mechanical workshops or have responsibility for the work done
there and the conditions under which it is performed. It deals with the most common
hazards in workshops. It is not intended to be fully comprehensive but to stimulate
and guide all personnel in the prevention of possible accidents. When special
machines or materials are used, full information on hazards and precautions must be
obtained from the supplier and be observed.
The attitude of the machine operator to the advice in this Code is of prime
importance. It is in his/her own interest, as well as that of others, to study the Code
carefully and apply it.
Skilled and experienced workshop users have a duty to maintain high standards in
safety practice and to set an example for others.
Supervision
Whilst ultimate responsibility rests with the Head of School and the University, it is
recognised that the workshop based technicians are highly skilled, knowledgeable
and have a special responsibility for ensuring safety, and they must take steps to
make sure that recommended procedures are adopted and that the workshop is kept
clean and tidy. They should ensure that individuals using machines in the workshop
are properly trained and students properly supervised. Individuals must comply with
any request from these members of technical staff when matters of health and safety
are involved.
32
Reported hazards should be investigated, examined and dealt with. Good planning
by supervisors will prevent many situations which may give rise to accidents.
Especially high standards of care are required for workshops used by students. Those
responsible for supervising or teaching in these areas must be familiar with the
detailed precautions in the relevant parts of this Code, and must see that advice and
supervision are given accordingly.
General Workshop Safety Rules
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Always seek instruction before using an unfamiliar piece of equipment.
Only use tools and equipment for their intended purpose.
Report all damaged equipment and do not use it until it has been repaired by a
competent person.
Report all hazards, unsafe conditions and work practices immediately to a
member of workshop staff.
Never use compressed air for cleaning clothing or machinery.
Remove ties, scarves, rings, watches, bracelets, necklaces, etc., and anything that
is loose and could possibly get caught in machinery.
Anyone with long hair should keep it contained in a cap. Tying it back may not
be enough.
General Housekeeping
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Keep the workshop clean and tidy at all times. Good housekeeping is one of
fundamental principles of accident prevention. To stumble or fall in a workshop
can have serious consequences, so floors must be kept free from tripping hazards,
grease, oil , water and anything else that could produce a slipping hazard. Waste
material should not be left lying around.
Swarf in particular should not be allowed to accumulate since this can penetrate
hands and feet causing infection.
Materials and components should be correctly stacked. Storage racks must be
stable and of sufficient strength for the amount of material stored.
Gangways, through and around the workshop should be clearly marked and kept
clear of obstructions at all times.
General Behaviour
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Always behave in a responsible manner. Pranks and horseplay can go wrong and
cause injury.
Walk! If you run in a workshop you may trip and fall on something, possibly
causing injury.
In general make sure that there is someone else present when working in a
workshop. Do not work on your own; there will be no one to help you if you
sustain an injury.
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You must obtain permission from the tutor or technician in charge and have
received the necessary training to enable you to carry out the work safely before
attempting to use any piece of power equipment.
Do not use personnel headphone equipment.
Never distract the attention of another person who is operating equipment.
Wear eye protection, contain long hair, remove tie, remove bracelets and rings.
Do not use any equipment that you have not been authorised to do so.
Personnel Protective Equipment
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Clothing
Everyday clothes should normally be covered whilst working in
mechanical workshops. In general lab. coats or boiler suits should
be worn in workshop areas. They should be in good condition and
have close-fitting cuffs, no loose belts, be in good repair, and be
worn buttoned or zipped up. They should not be allowed to become
heavily contaminated with oils etc. and should be laundered
regularly. Synthetic fibre materials should not be used.
Special protective clothing, such as aprons, leggings, gloves,
goggles, boots, should be provided for particular activities in, and
areas of the workshop e.g. welding and heat treatment.
Ear
Where possible, reduction of noise levels should be achieved by
Protection enclosing the source in sound damping materials. Only when this
is not practicable that personnel hearing protectors ear plugs or ear
defenders should be used. If the noise exceeds 85dB(A) then an
assessment must be made.
Eye
Wear eye protection both when operating a machine or process that
Protection may produce flying particles or when passing through such an area
When welding eye goggles or a face shield is required. See the
welding, brazing and cutting section for more details.
Foot
Wear safety shoes or strong leather type shoes in the workshop.
Protection Canvas shoes, sandals and other flimsy footwear provide no
protection against injury and are not permitted.
Hand.
Prolonged contact of the skin with oil, grease, cutting fluids etc.
Protection can cause skin problems. Wear disposable gloves if an
entanglement hazard is not present and/or barrier cream when
handling potentially hazardous or dirty materials. Be sure to wash
thoroughly when you have finished. Use the special-purpose hand
cleansing creams provided.
Head
Protective helmets should be worn when there is the potential for
Protection injury from falling objects
Respiratory Engineering control measures e.g. local exhaust ventilation, should
Protection be used to prevent the air, which is being breathed from becoming
contaminated with harmful dusts, fumes gases etc. When effective
engineering controls are not feasible then an appropriate mask or
respirator should be used.
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Safe Guarding of Machinery
Safeguards to prevent injuries, such as crushed hands and arms, severed fingers and
blindness are essential. Machine parts, functions, or processes that have the potential
to cause injury must be controlled or eliminated.
The basic areas requiring safe guarding are
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The point of operation - that is the point where the work process is being
performed e.g. cutting, shaping or milling.
Power transmissions components will also need to be included e.g. flywheels,
pulleys, belts, connecting rods, couplings, cams, spindles, chains, cranks and
gears.
Other moving parts including reciprocating, rotating, and transverse moving
parts, as well as feed mechanisms and auxiliary parts of the machines.
The ejection of material and machinery parts e.g. flying chips or sparks.
Guards
Guards are essentially barriers that prevent access to danger areas.
Point-of operation guards should
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Prevent hands or fingers from entering the danger area.
Conform to the maximum permissible openings.
Not create pinch points between the guard and moving machine parts.
Use fasteners that cannot be readily removed by an operator. Ideally specialist
tools should be required.
Facilitate inspection and maintenance of the machine.
Offer maximum permitted visibility of the point of operation.
There are four general types of guards.
a. Fixed – A fixed guard is a permanent part of the machine. It is not dependent
upon moving parts to perform its function. This guard is usually preferable to
other types because of its relative simplicity and permanence.
b. Interlocked – When this type of guard is opened or removed, the tripping
mechanism and/or power automatically shuts off or disengages, and the machine
cannot cycle or be started until the guard is back in place. An interlocked guard
may use electrical, hydraulic or pneumatic power or any combination of these.
Replacing the guard should not automatically restart the machine. To be effective
all movable guards should be interlocked
c. Adjustable – Adjustable guards are useful because they allow flexibility in
accommodating stock or work pieces.
d. Self-adjusting – The movement of the stock or work piece determines the
openings of these barriers. As the operator moves work into the danger area, the
guard is pushed away, providing an opening which is only large enough to admit
the stock or work piece.
35
Other Safety Devices
The following safety devices are in common usage perform the following functions
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Stop the machine if a hand or any part of the body is inadvertently placed in or
near the danger area. Examples of this type of device are photoelectric presencesensing devices, pressure sensitive matting and trip devices in close proximity to
the chuck on a radial drill. This type of device must only be used where it is
capable of stopping the machine before the worker can reach the danger area e.g.
linked a braking mechanism on radial drill.
Restrains or withdraws the operator’s hand from the danger area during
operation.
Require the operator to use both hands on machine controls, thus keeping both
hands and body out of danger. Because this device only protects the operator all
other personnel should be excluded from the vicinity whilst the machine is being
operated.
Remote control and distance guards which operate by physically removing the
operator and other personnel from the danger area.
Provision of a synchronised barrier within the operating cycle of the
machine/process which prevents entry to the danger area during the hazardous
parts of the cycle.
General Rules for Safeguarding
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Most workshop machinery is fitted with guards or other safety devices. While
the School has a responsibility to ensure that guards and safety devices are in
place, it must be emphasised that any person who causes an accident by wilfully
tampering with, removing or not replacing these safeguards is liable to
prosecution under the Health and Safety Act 1974. Also, it is illegal, as well as
dangerous, to operate an inadequately guarded machine.
The person about to use the machinery is responsible for ensuring that all safety
equipment e.g. guards and safety switches, are in position, correctly fitted and
functioning properly on any machine or piece of equipment, before they attempt
operate it. If the safeguards fails to function correctly or their effectiveness is
suspect, operation should cease immediately and a member of the workshop
should informed and the machine should be put out of commission until it can be
checked out and repairs have been effected. Ask if you are in any doubt.
When it is essential that guards are removed and/or safety devices are disabled to
allow maintenance work to be carried out, it is important that these safeguards are
restored immediately after the work has been completed. It should be noted that
before any safeguard is defeated the machine must be electrically isolated and
made safe, and left in a condition that does not allow for it to be inadvertently
started up again by anyone else and/or present a hazard.
The fixing of guards and safety devices should be such that special tool are
required for their removal.
Stock guards must be used for parts of the material which project beyond the
machinery.
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Bench Work and Hand Tools
Hand tools are non-powered tools, including spanners, hammers, chisels and
screwdrivers. While hand tool injuries tend be less severe than power tool injuries,
hand tool injuries are more common. The most common hand tool accidents are
caused by failure to use the right tool, failure to use a tool correctly, failure to keep
edged tools sharp and the failure to replace or repair defective tools. The following
are guidelines which should be followed when using hand tools.
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Select the right tool for the job. Every tool is designed for a specific purpose and
should only be used in a proper manner for their intended purpose.
Hand tools should be of a proper construction, made of good quality materials
and be in good working condition. Where needed handles of appropriate wood
should be of the correct size, securely fitted and checked regular.
Hand tools should only be tempered, dressed or repaired by a competent person.
The cutting edges of tools should be kept sharp. Dull tools can be more
dangerous than sharp. Heads of hammers, wedges, chisels and other shock tools
should be frequently dressed or ground.
Check all tools you use for signs of defects or damage before use. In case of
hammers ensure that the head is tightly wedged.
When sawing ensure you have the correct saw and blade for the job. Take slow
deliberate strokes. Forcing the cut can make the blade buckle and snap and/or
jump out onto your hand.
Hand tools should not be left lying in places where persons have to work or pass,
or on scaffolds or other elevations from which they might fall on persons below.
Keep screwdrivers in a state of repair. Check the handle and ensure in the case
the slot type ensure that it has a sharp square –edge to minimise slip out.
Do not use pliers as substitutes for spanners or wrenches.
Keep the floor area around the bench clear.
Always ensure that files have properly fitted handles of correct size. If you do
not, the tang may pierce your hand.
Do not use tools which appear to be damaged.
Use a copper, hide or lead hammer or a soft drift, if you need to strike hard
objects or machined surfaces. Hard-faced hammers on hardened surfaces could
produce dangerous flying fragments.
Use spanners of the correct size when tightening or slackening nuts and bolts. Ill
fitting spanners may fly off and injure you, as well as damaging the nut or bolt.
Adjustable spanners should be considered a last resort. To avoid sudden slips,
spanners should be pulled, not pushed. Be sure to be in a balanced position when
performing work. Handles etc. should not be extended by lengths of pipe or other
makeshift means. Penetrating oil is preferably to using blunt force.
Ensure all hand tools are stored correctly.
37
Portable Powered Tools
Electric powered tools should be of the single purpose type, double-insulated, of
robust construction and comply with BS 2769. Most power tools have some form of
cutter, abrasive disc or drill which is difficult to guard totally and consequently they
should only be used by skilled persons. In all instances suitable eye protection must
be worn. Common accidents associated with power tools include abrasions, cuts,
lacerations, amputations, burns, electrocutions an d broken bones. These accidents
are often caused by the following:o
o
o
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Touching the cutting, drilling or
grinding components
Getting caught in moving parts
Suffering electrical shock due to
improper earthing, equipment
defects or operator misuse
o
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Being struck by particles that
normally eject during operation
Touching hot tools or workpieces
Falling in the work area
Being struck by falling too
Familiarise yourself with the equipment before attempting to use it, read the
manufactures’ instructions if available and make yourself aware of the operation
of all risk control devices. Conduct a visual inspection of the machinery. Ensure
that all guards have been correctly placed and functioning properly. Check that
there are no obvious hazards present including damage to the electrics and control
mechanisms.
The use of cordless tools if practicable is strongly recommended. Serious
consideration should also be given to the use of 110 volt appliances. These are
normally supplied via. a centre–tapped transformer which means that contact
cannot occur without a potential greater than 55 volts, which in normal
circumstance s should not be fatal. It should be remembered however that even
the slightest shock can have serious consequences if operating machinery or
working at height. When only 240V versions of portable power tool are available
theses must be used in conjunction with a residual current device (RCD).
Select the correct bit, blade, cutter or grinding wheel for the job in hand. Always
operate tools at the correct speed for the job in hand. Working too slowly can
cause an accident just as easily as working too fast. Do not rely on force to
perform an operation. If the correct tool, blade and cutting speeds have been
chosen then excessive strength should not be required. You make be using the
wrong tool or have a blunt cutter/blade.
Ensure that the equipment is disconnected from its power before clearing jam sor
blockages.
Remember to remove chuck keys or adjusting tools prior to operation.
Secure work pieces with a clamp or vice to free the hands and minimise the risk
of injury.
Ensure that the associate electrical cable do not pose a tripping hazard. Avoid
running cables across floors.
Portable electric tools should only be used by trained competent personnel and
only for the purpose for which they have been designed.
Keep the equipment clean and dry and avoid standing on a damp surface whilst
using it.
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Machine Tools
General Rules to observe before starting any machining
 Do not operate any machine tool while under the influence of drugs, alcohol, or
any medication that could cause drowsiness.
 Ensure that you have received full instruction as to the dangers that can arise in
using the machinery and are familiar with any specific safety rules and
precautions that must be observed.
 Ensure that you have read and fully understood the operating instructions which
must be consistent with the manufactures’ recommendations. These ideally
should be prominently posted in the workshop close to the relevant machines or
processes.
 Only one person should normally operate a machine at a time.
 Ensure that you have been properly trained and are able to show proficiency in
both, the type of work being undertaken and the machines being used. Never
assume that you are capable unless you have been assessed as being so.
 Inexperienced operators such as students must not use any machinery until
authorised and proper supervision is in place.
 Staff and students must not work alone in the workshops when operating
potentially dangerous machinery or are engaged in potentially dangerous work
processes.
 Familiarise yourself with the method of quickly stopping the machine that you are
controlling. Ask for assistance if you are at all unsure how to control the machine.
 Conduct a visual inspection of the machinery. Ensure that all guards have been
correctly placed before the machine is started and any other designated risk
control devices are being used. Ensure that there are no obvious hazards present
including damage to the electrics and control gear.
 Ensure that you are not wearing gloves, watches, rings, bracelets or other
jewellery items. Ensure that no loose clothing, ties or pullcords are present and
that long hair is restrained.
 The intended machining lies within its design capacity and intended usage.
 Ensure that the machine is in good operating order, any cutting tools to be used
are correctly sharpened and the workpiece has been correctly located and securely
clamped.
 Ensure that dust and extraction systems where provided are turned on and
functioning correctly.
 Ensure where coolant is being used that the flow is adequate and properly
adjusted.
 Ensure that any feed mechanisms are in neutral.
 Ensure the area around the machine is clean tidy and free of obstructions.
Sufficient clear space should available to allow for easy movement and the
minimum risk of accidental interference from other personnel.
General Rules to observe whilst machining
 Always give your full concentration to the job when operating a machine. Stop
the machine if you have to pause to talk to someone.
 Stop the machine if you have to leave it unattended, even if it is only for a few
seconds or a few metres distance.
39
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Always wear eye protection when operating a machine.
Make sure that any machine you operate is in good order, properly adjusted and
lubricated. If it appears to you not to be so, report it to your Tutor and do not
operate the machine.
Never reach across a machine spindle or attempt to remove a jam whilst the
machine is in motion.
Check, where appropriate that the direction of rotation of the workpiece or cutter
is correct.
Stop the machine and isolate it electrically before cleaning it. Remove
machinings with a brush, stick or other suitable implement. Never use your bare
hands or compressed air.
Never use rags or other loose material around moving machine parts.
Never use calliper or gauge a work piece while the machine is in operation.
Do not press buttons, turn handles or move levers on any machine, other than the
one you are operating.
Specific guidelines for the use of drilling machines
Drilling machines are one of the most dangerous hand operated pieces of equipment
in a workshop area. Following safety procedures during drilling operations will help
eliminate accidents.
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Ensure that you have been properly trained in the use of the machine before
attempting any work and the appropriate supervision is in place.
Do not support the work pieces by hand. Securely fasten materials to the table to
prevent spinning using a clamp or vice.
Operators need to be aware of the danger of leaving chuck keys in chuck after
removing or replace drills.
Use a centre punch to mark the material before drilling.
The appropriate correctly sharpened drill for the job and material must be used
with the correct cutting angles, rake, length of cutting edge, lands and spiral.
Digging In can occur if incorrect cutting rakes are used and is the process by
which the drill claws its way into the material, causing snatching and eventual
drill breakage.
Ensure the drill machine is run at the correct speed for the size and type of drill
being used.
Avoid forcing or feeding the drill too fast as this can break the drill bit. Ease up
on the feed as the drill breaks through the work to avoid damage to the bit and
work piece.
Make sure that the drill is running true before starting any drilling operation.
Lock adjustable clamps and arms before drilling commences. Never make any
adjustments while the machine is operating.
Ensure that all rotating drive shafts are guarded and these guards are kept in place
while the machine is operating. This includes the spindle, chuck, and belt and
pulley system.
If the flutes of the drill become choked with swarf, the machine must be stopped
before the swarf is removed. Swarf must not be removed by hand. A suitable
brush should be used instead once the spindle has stopped rotating.
Frequently back the drill out of deep cuts to clean and cool the bit.
40
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Always wear eye protection and ensure all loose clothing is kept away from the
rotating drill bits. It is normal practice to remove ties. Ensure that long hair is
restrained and never wear gloves or jewellery etc. Bandages also provide a
source of entanglement.
A properly designed drift should be used to remove tapered drills or chucks from
the spindle.
Specific guidelines for the use of lathes
 Ensure that the chuck or face-plate has been securely locked onto the spindle
nose.
 Special care must be taken to see that the chuck key has been removed from the
chuck before the lathe is turned on. When not in use the key should be stored in a
clip or clear of the lathe.
 Take care to ensure that the chuck key fits correctly to prevent slippage and
damage to the operator, especially to the hands.
 Special care is called for when screwed –on chucks are run in reverse.
 The work piece must be securely held in the chuck using the full length of the
chuck jaws. Work not held in this manner will frequently fly out when the lathe
is switched on or even a light cut is attempted.
 Work held on a face-plate must be firmly secured and , when offset from the
centre line, the face plate and work must be suitably counter-balanced.
 Make sure that all gear and belt guards are in place. Chuck guards must be fitted
and used where practicable.
 A check should be made before switching on to ensure that a complete cut can be
taken without fouling the toolpost or lathe saddle.
 Cutting tools should be kept sharpened and when clamped in the toolpost this
should be done by tightening evenly to reduce strain.
 Whenever possible the saddle should be locked onto the bed.
 Care should taken setting up, as the hands can receive very deep cuts if they are
knocked or caught on the cutting edges of tools. The back of the hand is
particularly vulnerable to such injury.
 Incorrect cutting angles can lead to the digging-in of tools in the work piece. The
cutting edge should be at the centre line of the work piece. Incorrect cutting
angles, setting tools below centre line and worn edges can lead to riding up of the
work on the tool, causing the work to be wrenched from the chuck and flung out
and/or tool breakage.
 Swarf leaves the cutting edge of the tool as either a continuous or discontinuous
chip. The use of a special tool may be required to prevent the production of long
lengths of swarf. Swarf must not be allowed to accumulate in the lathe tray or on
the floor, or build up and become entangled around the tool or work piece. With
discontinuous chips there is a danger that pieces may be flung out to a
considerable distance. The eyes in particular are very vulnerable to this danger.
 There is a significant danger from flying swarf, especially at high cutting speeds.
Apart from the possibility of deep cuts to the operator or other personnel in the
vicinity the chips may leave the tool in a red hot state leading to burns and the
risk of fire. The work pieces themselves can become hot enough to burn the
hands if heavy machining has taken place.
41


A stock bar projecting beyond the headstock must be guarded throughout its
entire length.
A tailstock and in some cases steadies should be used when turning long lengths
of material.
Specific guidelines for the use of shaping machines
 The ram must be fully guarded throughout the operating movement and guards
must not be removed while the machine is in use.
 The machine should always be operated from the control side.
 The stroke of the ram should always be kept as short as possible while ensuring
sufficient non-cutting length at each stroke. This distance will vary with the
stroke speed.
 The stroke of the machine should not be set to allow the cutter to gobeyond the
front edge of the table.
 Work pieces should be securely fixed to the table and be able to resist the forward
stroke of the ram.
Specific guidelines for the use of milling machines
 All mating surfaces of the arbour must be clean and free of grit before engaging
into the drive spindle. The same applies to arbour collars, the locating faces of
the milling cutter, chucks and face mills which are locked directly onto the
spindle nose. Care must be taken to ensure that any securing bolts are tightened
evenly.
 Arbour drive keys should fit the keyways snugly and should be replaced when
they show signs of wear.
 The arbour support carrying the bearing should be placed as close to the cutter as
possible and positioned so that it will not foul the work piece or vice, during
machining.
 The distance between the spindle nose and the arbour support should be kept to a
minimum.
 Ensure that any feed mechanisms are disengaged before starting the machine.
Before engaging automatic feeds ensure that the table traversing handle is
disengaged. Most modern machines are designed with a springloaded handle
which ensures it is held in a disengaged position. Care must be taken not to
engage ‘rapid’ feed in the forward direction on milling machines so equipped.
 Work held in a machine vice must be securely clamped. If the work piece is
supported on a packing piece in the vice it should be tapped down using a mallet.
 Never use a horizontal milling machine without an effective cutter guard.
 Never remove safety limit stops or use them as length trip stops.
 Always ensure that cutters are rotating in the correct direction
 Always stop the cutter spindle when not actually cutting.
 Always electrically isolate the machine when changing a cutter or arbour.
 Use arbour support and knee-braces if required.
 Handle milling cutters carefully – they have sharp edges.
 Always replace the gear- train cover on a dividing head after adjustment.
 Never use a milling cutter with even one damaged tooth.
 Never use damaged adaptors, taper sockets, taper shanks, keys etc.
42


Never remove a component from the table by inserting the fingers in a tennon or
‘T’ slot.
Always ensure that the draw bolt on a vertical milling machine is properly
engaged and/or tightened.
Specific guidelines for the use of powered saws
 When using power hacksaws the automatic knock-off switch should be used at all
times and regular check s should be conducted to ensure that it is in good
working order. The work must be secured, adequately supported and the length
of any overhang protected or clearly indicated to prevent it becoming a hazard.
 When using bandsaws ensure :a. The correct tooth-pitch blade and bandspeed for the material being sawn.
b. The tension and tracking of the blade have been checked and are correct.
c. The guide rollers have been correctly set.
d. As much of the blade is guarded as possible – adjust top guard to just clear
work piece.
e. That no adjustments are made whilst the bandsaw is in use.
f. Use a ‘Push Stick’ when feeding the work pieces through the saw.
g. That the work table is kept clean.
Specific guidelines for the use of sheet metal working equipment
 When using Rolls and Bending machines, care should be taken to prevent fingers
etc. being caught in the mechanism. Bending machines should always be left in
the closed position when not in use.
 When using guillotines ensure :a. That appropriate guarding has been fitted to ensure that fingers etc. cannot
come into contact with the shearing blades and requires guarding against
access from the rear as well as the front. If fixed guards are not practicable
then there must be an interlocked guard. Consideration also needs to be given
guarding against material falling as part of the guillotine process.
b. Hand-operated are made inoperative when not in use either by the removal of
the handle or by the use of a locking or similar device.
c. The shear edges of the blades are maintained in good condition and the blade
clearance have adjusted in accordance with the manufacture’s instruction, and
are appropriate to the thickness and type of material being cut.
Specific guidelines for the use of grinding machines
 The most serious hazard associated with the use of abrasive wheels is the bursting
(explosion) of a wheel of wheel whilst in motion. This can happen as a result of
incorrect speed, faulty mounting and operator error/misuse. Abrasive wheels
therefore must be properly mounted and dressed by competent personnel who
have attended an authorised course of instruction.
 Wheels should be periodically checked for soundness and never use a wheel that
has been dropped.
 Do not grind non-ferrous metals.
 Do not use a cracked or badly worn wheel and only mount wheels on machines
they are intended for.
 Check the wheel rotation before grinding and allow the grinder to reach full speed
before commencing any grinding operation. N.B. The breakage of faulty wheels
43












is usually associated with a change of inertia e.g. at the start of an operation or
when it is slowing down.
That any coolant being used is turned off when the wheel is stationary.
The most common accidents are caused by particles flying from the wheel.
Ensure that transparent face guards/eye shields are fitted, clean and properly
adjusted. Use you use the correct eye protection during grinding a minimum of
safety spectacles and ideally a faceshield.
That any work-rest is positioned as close to the wheel face as is reasonably
practicable to prevent the work piece jamming between the wheel and rest. The
minimum distance should be 2mm.
The side of straight wheels should never be used for grinding unless it has been
specifically designed for this purpose.
Work should never be forced against a cold wheel as sudden heating up may
cause it to burst.
Ensure that the dust extraction is sufficient.
Take great care to ensure that no loose rags etc. are left or used near grinding
wheels.
Finishing machines should be guarded with only the work face belt exposed and
the belt should be mounted such that it rotates away from the operator wherever
practicable. Before use the condition of the abrasive belt should be examined and
replaced if worn and the correctness of the tracking of the belt should be checked
by rotating the belt by hand.
Where possible suitable jigs and fixtures should be used to hold and/or locate the
work piece.
Ensure that the grinder is stable and secure/anchored.
A double headed abrasive wheel must not be used by two persons simultaneously
When surface grinding ensure :a. The table limit stops have not been removed.
b. The work and vice if used are securely held. Methods for holding work on
the surface grinder have much in common with those used for milling
machines. Magnetic table are now used extensively. These must be large
enough to ensure that there is no work overhang. Work should be placed so
that the maximum area of pull of the magnetic poles is achieved. The surface
of the work in contact with the magnetic table should be smooth to ensure a
good magnetic contact. A magnetic table should only be used for work with a
high iron content which gives a good magnetic hols ensuring that no slip
takes place during the grinding stroke.
c. Operators must not have their hands on the machine when it is auto-traversing
as there is a danger that fingers may be injured by the reversing dogs. A
hinged cover should be fitted over the traversing trips.
44
Welding, Brazing and Cutting
General Hazards
 Eye injuries
During any welding, cutting or brazing operation, the eyes may
be injured by sparks, spatter, slag and other foreign bodies.
Suitable eye protection or face shields must be used.
During gas welding, infra-red and visible light rays are emitted.
Infra –red may dry the outer surface of the eyes which will then
become irritated. Goggles should be used for gas welding and
for all classes of brazing with the exception of silver soldering
where clear glass goggles should be used.
Both intense ultra violet radiation, to which the eyes are very
sensitive, and infra red rays are generated during arc welding.
The effect of UV radiation on the eyes may vary from
conjunctivitis to photo keratitis (welder’s flash) and in extreme
cases blindness. Even momentary flashes are extremely
dangerous to the eyes. A face shield should be used when arc
welding.
Welding or Cutting operation
Torch soldering
Torch brazing
Oxygen Cutting
Gas Welding
Shielded metalarc welding (stick)
electrodes
Gas metal-arc
welding (MIG)
Gas tungsten arc
welding (TIG)
- Light
- Medium
- Heavy
- Light
- Medium
- Heavy
- Non-ferrous base metal
- Ferrous base metal
Electrode Size
Metal Thickness or
Welding Current
Filter
Shade
Number
Under 1in (25mm)
1 to 6ins (25 to100mm)
over 6ins (150mm)
Under 1/8in (3mm)
1/8 to 1/2in (3 to 12mm)
Over 1/2in (12mm)
Under 5/32in (4mm)
5/32 to 1/4 (4 to 6.4mm)
Over 1/4 (6.4mm)
All
All
2
3 or 4
3 or 4
4 or 5
5 or 6
4 or 5
5 or 6
6 or 8
10
12
14
11
12
All
12
Table of lens shades for welding and cutting

Heat stress
Welding operations may produce sufficient heat energy to
become a heat stress problem for the welder, especially when
working in poorly ventilated or confined areas.

Electrocution
There is always the possibility of an electric shock when arc
welding. There should an efficient and convenient means of
switching of the power. See electric arc welding section.
45

Manual
Handling
Strains etc from handling material and equipment. An
assessment may need to be carried out.

Burns
Skin burns may result from metal splatter or touching hot work
pieces. Always mark hot metal with a warning sign, date and
time, when welding, brazing or cutting operation is complete.
Appropriate personal protective equipment (PPE) which protects
the welder from hazard. Examples of PPE commonly used by
welders are. gloves, boots overalls and aprons.

Radiation
Ultraviolet, visible and infrared. Causes damage to the skin and
eyes. Protection should be used for the face and the eyes
(suitable welding shield) and body (suitable clothing). People in
the area, particularly when arc welding is taking place, should be
protected by suitably positioned, non–reflective, noncombustible curtains or screens.

Fumes
The hot metal from the weld pool will produce fumes when the
vapour is rapidly cooled and oxidised by the surrounding air.
The fumes consist of fine particulate, between 0.001µm and
100µm in diameter, predominately oxides of the metals being
used. As these particles can be extremely small, they can
penetrate the innermost parts of the lung causing irritation of the
respiratory tract, metal fume fever and siderosis (deposition of
iron particles in the lung). The OEL for welding fumes is
5mg/m3 (8hr time weighted average). Ensure adequate
ventilation and exhaust is available and being used. Never weld
with head in the fumes and gases rising from the work.
Ventilation should be arranged so that the welding fumes are
drawn away from the welder’s breathing zone.

Gases
Shielding gases used in arc welding e.g argon. Ozone is
produced by the high energy arc.
Harmful gases, principally nitrous oxide and carbon monoxide
are generated during gas welding.
Gases are also produced by the effect of heat on solvent vapours
or surface contaminants on the metal.
Special care must be taken in confined spaces to avoid oxygen
depletion.

Systemic
Poisoning
The fumes from galvanised metals, lead coatings, specially
treated, or other toxic metals may not only affect the respiratory
system but also the rest of the body, particularly when the work
is conducted at length in poorly ventilated areas.

Fire and
Explosion
When any type of welding takes place, the naked flame , or arc,
and sparks provide an ignition source. Take care to prevent
these from starting a fire. All combustibles material and
46
flammable liquids should be removed from the area. Period
checks should be made of the area for combustible atmospheres.
Safe usage of cylinders in welding and cutting operations
 All cylinders must be used and stored in the vertical position, especially acetylene
and securely supported either by clamps, chains, in a special purpose stand or
welding trolley.
 Regulators should be physically checked every 5 years.
 Use BS EN 559, ISO 3821 or their equivalents to connect the cylinder to the
welding equipment. These have reinforced outer protective covers and resistant
linings. The following colour codes should be used:- red (acetylene and other
fuel gases except LPG), orange(LPG), blue(oxygen) and black(non-combustible
gases). Use connectors which are appropriate for this tubing.
 Follow practices outlined the British Compressed Gases Association Code of
Practice CP7 – The safe use of oxy-fuel gas equipment.
 The cylinder valve key must be kept readily available e.g. chained to the trolley,
to facilitate closing of the cylinder valve in the event of an emergency.
Guidance for Gas Welding
In gas welding, metal fusion is achieved by the use of very high temperature flames
produced by mixture of gases at a torch or blowpipe. The gases involved are oxygen
and a fuel gas e.g. acetylene or LPG.
Use of Oxygen


Oxygen has no smell and is not in itself flammable but is excellent supporter of
combustion. Therefore, excessive oxygen can be extremely dangerous.
Such substance as oil and grease are liable to burst into flames in the presence of
a concentration of oxygen. An oxygen regulator must be used which must not be
lubricated in any way.
Use of Acetylene





Acetylene is extremely flammable and may form an explosive mixture with either
air or oxygen. Its flammability range is 2.4-88 vol% in air. Acetylene is
classified as a flammable compressed gas which can, under certain conditions,
decompose into its constituent elements of carbon and hydrogen with explosive
results.
Cylinders are protected by pressure release devices, which normally consist of a
fusible plug located at the bottom of the cylinder.
Acetylene forms explosive acetylides with copper, silver and mercury. Do not
use with alloys containing more than 70% copper or 43% silver.
A flashback can occur if there is a flammable mixture of fuel gas and oxygen in
the hoses when the torch is lit. If not stopped, the flame will ignite the mixture
and will travel backwards from the torch, along the hoses, through the regulator
and into the cylinder.
A flashback can trigger decomposition of the acetylene in the fuel hose, in the
regulator and in the cylinder itself.
47





Flashback arrestors must be fitted to both the acetylene and oxygen cylinders.
For long lengths of hose, fit arresters to both the blowpipe and the regulator.
Non-return (check) valves must be fitted to the torch to prevent backfeeding of
gas into the hoses.
Non-return valves and flashback arresters should be checked regularly.
If a flashback occurs immediately close the cylinder valves, both acetylene
and oxygen, if it is safe to do so. The flame should go out when the acetylene
is shut off. If the flame cannot be put out at once or the cylinder becomes
warm or starts to vibrate, evacuate the building immediately and call the
emergency fire services and the gas supplier BOC
Before using again check the flashback arresters and other components which
may have been damaged by the flashback.
The following HSE regulations exist for the use of acetylene : For use at pressure over 1.5 bar. Consult the Explosive Inspectorate, St Anne’s
House, Stanley Precinct, Bootle, Merseyside, L20 3RA. Tel. 0151 951 4025.
 At pressures between 0.62 bar and 1.5 bar Requirements of the HSE
Exemption Certificate 2/89 have to be met. Ensure equipment has been designed
to met the exemption criteria. If in any doubt, contact the Explosive Inspectorate.
 Below 0.62bar Refer to British Compressed Gases Association Code of Practice
CP6 – The safe distribution of acetylene in the pressure range 0 -1.5bar.
Blowpipes and Hoses




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




Ensure the correct gas pressures and nozzle sizes for the job are being used.
Nozzles should be checked regularly to ensure they are damaged or blocked by
dirt or spatter.
Do not hold nozzle too close to the workpiece. The nozzle can overheat and
cause flashback.
Ensure regulators, connections, lines and blowpipes are to the correct
specification and leak free.
Keep hoses out of doorways, gangways and away from other people. Not only
will they present a tripping hazard, a flattened hose can cause a flashback.
Before lighting the blowpipe, purge the hoses by opening the gas supply to each
hose for a few seconds. This will flush out any flammable mixtures of gases in
the hose. Purge one hose at a time and close the blowpipe after purging. Use a
well ventilated area.
Use a spark ignitor to light the gas other wise severely burnt fingers can result.
Hoses of equal length should be used for oxygen and the fuel gas.
Sufficient length of hose should be allowed for the welder to manoeuvre the
blowpipe. A sudden jerk or pull on the hoses is liable to pull the blowpipe out of
the welder’s hand, cause a cylinder to fall over or a hose connection to fail.
Hoses should be inspected frequently to ensure that there are no cuts or cracks.
Guidance for arc welding
MMA Manual metal arc welding. Uses flux coated electrodes which are replace by
the operator as they are consumed. No shielding medium in the form of gas
from a separate source is provided for the arc or molten metals.
48
In all MMA welding, the operator works close to the live electrode and the
workpiece and is therefore in danger of receiving an electric shock or being
burned from by the arc or hot metal. The welder may also be at risk whilst
changing electrodes.
MAG Metal active gas welding. Uses consumable wire electrode and supply of
active gas or gases. Flux cored consumables are included in this category.
MIG Metal inert gas welding. Uses a consumable wire electrode and a supply of
inert gas.
TIG Tungsten inert gas welding. Uses a tungsten electrode which is not consumed
and supply of inert gas.
To guard against electric shock and burns, the HSE recommend the following
measures: the arc must never be ‘struck’ without the face-shield being in its protective
position where it must be kept until the arc is extinguished.
 be careful where you put down the electrode holder. If you stop welding for a
short time, DO NOT put it on the face shield, clothing or rags, since it may still
be live at 80V or hot enough to cause damage. An insulated container or hook is
recommended. When you have finished welding, switch off the power supply
and remove the electrode from the holder.
 ensure welding equipment conforms to the appropriate parts of BS638.
 welding equipment must only be installed by qualified personnel who should
ensure that the equipment is installed, connected and used in accordance with the
manufacturers recommendations.
 ensure electrode-holders and connectors must be insulated to prevent inadvertent
access. The must be rated to carry the current safely. Connections must be clean
and tight.
 ensure welding and return leads are insulated and thick enough to safely carry the
current. Poor or faulty insulation may cause short circuiting or by-passing by
other conductors which they may come into contact with.
 always place the welding return lead as close as possible to the point where the
welding is being done.
 the equipment should be checked regular daily or before use and any damage or
worn components repaired or replaced.
 appropriate personal protective equipment should be selected to suit the hazards.
Gloves , boots and overalls aprons will protect welders from electric shocks and
burns to some extent, though it is recognised that it may not all be needed all of
the time.
 stand or kneel on a mat made from dry insulating material.
 ensure that someone is in attendance immediately outside the welding area.
 additional care should be taken in the following circumstances: where freedom of movement is restricted.
 when working in cramped conditions.
 when in contact with conductive parts.
 when working in areas where contact with fully or partially enclosed
conductive parts is likely.
 welding in wet, damp or humid conditions that reduce skin resistance and
insulting properties of the equipment.
49
Earthing of arc welding systems
Earthing of the workpiece is used to provide protection against internal insulation
failure of the welding transformer, by keeping the workpiece at or near earth potential
until a protective device (e.g. fuse or circuit breaker) operates to cut off the mains
supply. Where the welding circuit is not adequately insulated from the earthed
reference mains supply, the workpiece should be earthed. The workpiece earthing
conductor should be robust enough to withstand possible mechanical damage and
should be connected to the workpiece and a suitable earth terminal by bolted lugs or
secure screw clamps. Earthing tests should be carried out a regular basis.
If an alternative method of protecting against welding transformer insulation failure
is used, then by not earthing the workpiece or the welding output circuit, all of the
hazards caused by stray welding currents can be avoided.
The following are earthing classifications :a. Transformer Casing:Class I appliance - Earthed
Class II appliance - Not earthed
b. Transformer Secondary:Earthed
This is an obsolete type of equipment and should be taken out of
service. Failure of the weld return connection might not be
noticed, and damage to other earthed metallic parts could result.
Isolated
The absence of a weld return conductor will prevent welding
being carried out. However a failure of insulation within the
welding set could cause the work item to become live at 240V or
400V(three phase equipment). For this reason the workpiece
should be earthed.
Isolated with
double or
reinforced
insulation
This is most recent standard to which equipment is being built.
Because of the strengthened insulation, the workpiece need not
be earthed. Furthermore, to prevent the possibility of stray wild
return currents in the supply system earth conductors, it is
recommended that the workpiece is not earthed.
Brazing
Fume extraction is absolutely essential as most brazing rods contain percentages of
zinc, phosphorous, copper etc. In addition, many brazing fluxes are corrosive and
toxic fume-producing. The corrosive fluxes are usually removed when brazing is
completed.
Silver soldering may be considered a brazing process. Many of the propriety low
melting point silver solders contain cadmium which is an extremely toxic fume
producer and on no account should these fumes be breathed in during a silver
soldering operation. Efficient fume extraction is essential.
50
INDEX
Accidents at Work
iv,vi
Noise
23
Arc Welding
48
Organisation of Health and Safety
2
Bench Work
37
Out of Hours Working
5
Personal Protective Equipment
24
Brazing
45,50
Chemical Agents Directive
10
Pressure Equipment
25
Chemical Reaction Categories
10
Portable Power Tools
38
Power Saws
43
Chemical Safety
Classification of Electrical Equipment
Clothing
COSHH Assessments
9,10
16
Pressure Equipment
10,21,24
10
25,34
Pressure Systems
25
Procedures for Serious & Imminent Danger
v
Cryogens
11,12
Radiation
26,27
Display Screen Equipment
13,14
Raising Health and Safety Concerns
3
Drilling Machines
40
Reporting Accidents and Incidents
3
Earthing of Arc Welding Systems
50
Residual Current Devices
16
Electric Shocks
15
Risk Assessments
6,7
Electrical Safety
15,16
Safety Devices
36
Eye Protection
10,24
Safe Operating Procedures
6
Fire Hazards
36,45
Safety Rules
8
Scaffold Towers
30
School Health and Safety Committees
2
Fire Emergency Instructions
Gas Cylinders
ii
19,47
Gas Welding
47
School Health and Safety Plans
3
Grinding Machines
43
School Health and Safety Structure
4
Guards
35
Shaping Machines
42
Sheet Metal Working Equipment
43
Hand Tools
21,37
Health and Safety Information
7
Slips
28
Heating
31
Smoking Policy
5
Housekeeping
33
Supervision
32
Hygiene
42
Temperatures
31
Illness at Work
iii
Trips
28
Individual Responsibilities
2
University Codes of Practice and Policies
5
Ladders
30
Vacuum Systems
29
Ventilation
31
45
Lasers
26,27
Lathes
41
Welding
Lighting
31
Working at Heights
29,30
21,39
Work Environment
31
Work Equipment Regulations
22
Machine Tools
Manual Handling
Mechanical Safety
20
21,32
51
Workshops
21,32