RISK ASSESSMENT FOR THE CLEANING AND DEMOLITION OF CHIMNEYS FROM THE
ENEMALTA POWER STATION, MARSA.
1. PREAMBLE
1.1
1.1.1
1.1.2
1.1.3
1.2
1.2.1
1.2.2
1.2.3
1.2.4
1.2.5
1.3
1.4
The hazards associated with toxic air quality in chimney stack demolition are those
associated with the following risks:
toxic atmospheres existing in the confined spaces,
flammable and toxic chemicals in the residue deposits on the walls and furnace,
noise and vibrations as part of the demolition works.
The local Legal Notices that governs the entry into the Enemalta Chimneys are the
following:
The Work Place (Minimum Requirements for Work) (Confined Spaces and Spaces having
Explosive Atmospheres) Regulations, 2004, L.N. 41 of 2004. This LN transposes Directive
1999/92/EC of the European Parliament and of the Council on minimum requirements for
improving the safety and health protection of workers potentially at risk from explosive
atmospheres. The European Commission published a Non-binding guide to good practice
for implementing Directive 1999/92/EC “ATEX” (explosive atmospheres).
The Protection of the Health and Safety of Workers from Risks related to Chemical Agents
at Work Regulations, 2003, L.N. 227 of 2003, as amended by Legal Notice 353 of 2007 and
53 of 2012.
The Protection of Workers from the Risks related to Exposure to Asbestos at Work
Regulations, 2006, L.N. 323 of 2006.
Work Place (Minimum Health and Safety Requirements for the Protection of Workers from
Risks resulting from Exposure to Noise) Regulations. L.N. 158 of 2006.
Work Place (Minimum Health and Safety Requirements for the Protection of Workers from
Risks resulting from Exposure to Vibration) Regulations L.N. 371 of 2005.
Based on these LN’s, the request submitted by Enemalta asserts the removal and transfer of
toxic residues and contaminated material, present in the chimneys that are earmarked for
demolition.
DDE ATTARD Ltd, shall consider the following assumptions, which shall be verified and
certified:
1.4.1 The chimneys have been used exclusively for HFO combustion at least for the past 5
years.
1.4.2 Prior to entry into the chimney by DDE Attard personnel, a Confined Space entry
permit shall be issued by the contractor as required in L.N. 41 of 2004 (see Annex 2).
1.4.3 All the toxic and hazardous waste shall be transferred to appropriate containers, as
approved by MEPA and the OHSA, for eventual disposal or treatment, according to EC
Directive 20013/33/EC for final destruction locally or overseas following agreement
with MEPA. The waste shall become the sole responsibility of DDE Attard as soon as
demolition is commissioned.
2. HAZARDS ASSOCIATED WITH CHIMNEY CLEANING AND DEMOLITION.
2.1
Although identifiable hazards found in a regular workspace can also be found in a confined
space, the same hazards are far more hazardous in a confined space than in a regular
worksite.
2.2 Hazards in confined spaces such as the Enemalta chimneys, include the following hazards
which shall be addressed in this RA:
2.2.1 Poor air quality: The atmosphere might contain a poisonous substance such as fine
particulate matter that could make the worker ill or even cause the worker to lose
consciousness.
2.2.2 Natural ventilation alone will not be sufficient to maintain breathable quality air. Air
quality may not be uniform throughout the length of the chimney due to inexistent air
currents and localised residues of volatile or particulate chemicals.
2.2.3 Chemical exposures may lead to skin contact or ingestion as well as inhalation of 'stale'
air.
2.2.4 Fire Hazard: There may be an explosive/flammable atmosphere due to residual
flammable gases and combustible dusts which if ignited would lead to fire or
explosion.
2.2.5 Noise and vibrations from reverberations inside the chimneys.
2.2.6 Safety hazards such as moving parts of equipment, structural hazards, entanglement,
slips, and falls.
2.2.7 Temperature extremes including atmospheric and surface.
2.2.8 Shifting or collapse of bulk material.
2.2.9 Visibility.
2.2.10 Biological hazards.
2.3 The possible outcomes of these hazards include:
2.3.1 The entrance/exit of the confined space might not allow the worker to get out in time
should there be a surge of toxic air.
2.3.2 Self-rescue by the worker is more difficult.
2.3.3 The dimensions and the distance separating the manholes renders rescue of the
victims more difficult.
2.3.4 The interior configuration of the confined space often does not allow easy movement
of people with breathing or working equipment within it.
2.3.5 Work activities may introduce hazards not present initially.
3.
ENTRY PERMITS INTO A CONFINED SPACE.
3.1
The basic information that one would include in order to apply for an Entry Permit, are the
following:
3.1.1 Full details including dimensions and accessibility where exactly the work is to be
carried out.
3.1.2 Clear identification of the work to be undertaken.
3.1.3 Hazard identification, including hazards due to the environment of the Chimney.
3.1.4 Current air quality and residues earmarked for removal.
3.1.5 Precautions that shall be projected to be undertaken, the person undertaking the
precautions, as well as a checklist to show that the safety procedures are being
followed
3.1.6 The personal protective equipment required.
3.1.7 An estimate of when the work will begin and when it is expected to end.
3.1.8 Time table of works including personnel shift work.
3.1.9 Procedure for handback, plant ready for testing and decommissioning.
3.1.10 Reports on any anomaly encountered during the work.
4
ENSURING SAFE AIR QUALITY ACCORDING TO OCCUPATIONAL HEALTH AND
SAFETY STANDARD LIMITS
4.1
Prior to the commissioning of the works, and as part of the Confined Space Entry Permit, the
following guidelines shall be used with respect to the analytical measurements of parameters:
4.1.1 A thorough inspection of the furnace and chimney to identify and sample possible residues
or material that may contain asbestos fibres.
4.2
The inhalable particulate dust levels, measured as PM10, shall be lower than 10mg/m3
which is the recommended limit by the UK HSE,
4.3
4.4
4.5
4.6
4.7
4.8
4.9
4.10
4.11
4.12
4.13
The respirable particulate dust levels, measured as PM2.5, shall be lower than 4mg/m3
which are the recommended limit by the UK HSE.
The oxygen content in the confined space should be controlled to less than 23% but
maintained at levels greater than 18%.
Samples of residues shall be measured for pathogenic bacteria.
During the cleaning operation, continuous ventilation shall be provided at volumes and flow
rates sufficient to ensure that the oxygen content is maintained at or above 19.5 percent and
below 22.0 percent by volume.
During the cleaning operation, the following parameters shall be monitored in order to verify
compliance to safety limits:
4.7.1
Air-borne asbestos fibres, subject to their identification in the initial inspection,
every 4 hours.
4.7.2 Oxygen levels every 2-3 hours.
4.7.3 Inhalable and respirable particulate dust levels every 8 hours.
Forced mechanical ventilation shall be provided, with a warning system in place to
immediately notify the workers in the event of a hazard or a failure in the ventilation
equipment.
The air being provided by the ventilation system to the confined space shall be 'clean'
throughout the entire space.
In view of the danger of pockets of toxic gases or particulates still remaining inside the
chimney, even with the use of mechanical ventilation, air movement shall be ensured to have
a smooth flow throughout the confined length of the chimney.
Air being removed from the confined space is exhausted away from workers on the outside of
the chimney areas.
No work using flames shall be used prior to the complete removal of potentially combustible
material and the issue of a safe entry certificate.
No electric power tools shall be used, although lighting shall be used using explosion proof
light sources, with switches being isolated far away from the area of the tanks.
5 ASBESTOS RISK ASSESSMENT (if applicable)
5.1
5.1.1
5.1.2
5.1.3
5.1.4
5.1.5
5.1.6
5.1.7
5.1.8
5.1.9
5.1.10
5.2
The detailed information described below was based on several laws and guides, including:
The Analysts Guide for sampling analysis and clearance procedures, The Health and Safety
Executive of the UK.
NOHSC:2002(1988) (Australia) Code of practice for the safe removal of asbestos.
LN 228 of 2001 (Malta) Prevention and reduction of Emission Pollution by asbestos
regulations.
The Protection of Workers from the Risks related to Exposure to Asbestos at Work
Regulations, 2006, L.N. 323 of 2006.
LN 44 of 2002 Workplace health and safety requirements.
Several EC Directives and Guidelines, 83/477/EEC, 87/217/EEC, 91/382/EEC, 98/C
142/01 on the protection of workers from the risks related to exposure to asbestos at work.
EPA 1991 (USA) Demolition practices under the asbestos NESHAP regulations, Section 1Non friable materials.
OSHA ID-160 (USA) Determination of asbestos fibres in air (LD 0.1 f/mL)
Metodo UNICHIM N578 Determinazione delle fibre di amianto.
The Enemalta Asbestos Policy Document, dated 28th March 2008, Version 3.0, issued with
the tender.
Objectives of the Initial Inspection and Identification of Asbestos Material inside the
Chimney shall be:
5.2.1 The exact location, type and quantity of ACM identified.
5.2.2 The Condition of the asbestos material.
5.2.3 Establish the Standard Operating Procedures for work, exposure control and personal
protection methods to be used, including:
5.2.3.1
Training of Staff.
5.2.3.2 Works Schedule.
5.2.3.3 Safety against physical injuries.
5.2.3.4 Safety against asbestos hazards.
5.2.3.5
Isolation of dismantling area.
5.2.3.6 Emergency contingencies.
5.2.3.7
Brief of basic equipment.
5.2.3.8 Details provision of hygiene facilities.
5.2.3.9 Types of vehicles and equipment.
5.2.3.10 Type of health surveillance programme
5.2.3.11 Documentation and Forms.
5.3
5.3.1
5.3.2
5.3.3
5.3.4
5.3.5
5.3.6
5.3.7
5.3.8
The following mitigation measures shall be undertaken in case asbestos fibre materials are
identified following the initial inspection:
The mitigation measures that shall be adopted, should be able to control the airborne
asbestos levels to the local and EU limits of 0.1 fibres per milliliters, according to LN 323 of
2006.
The area shall be cleared from encumbering materials that may interfere with the operation
or pose a safety hazard.
The panels, bricks or other asbestos-containing material, shall be sprayed with a solution of
polyvinyl acetate (sealer), and the panels enclosed in polyethylene sheets.
The material shall be carefully loaded on appropriate hoists and jigged down to ground
level.
Control advice notices will be posted at prominent sites in the area of the respective sheds.
The area shall be decontaminated from ACM fragments at the end of the removal
programme. Air tests will be carried out to measure the fibre counts prevailing, prior to the
issue of the free/safe entry certificate. The progress of the dismantling programme will be
subject to the results of the air tests that shall be conducted by Dr George Peplow.
Workers issuing out of the isolated area shall wear disposable over-suits, which will be
removed in a clean area, located in an appropriate mobile decontamination caravan, where
they may change into clean clothing, to proceed to the adjacent shower rooms.
The transport and temporary storage of the material shall be conducted in steel containers,
stored at the DDE Attard scrapyard at Luqa.
6 SAMPLING STRATEGY ACCORDING TO EN 14899
6.1
6.1.1
6.1.2
6.1.3
6.1.4
6.1.5
6.1.6
6.1.7
6.2
6.2.1
6.2.2
6.2.3
6.3
6.3.1
The following sections are described in EN 14899, which is the guideline that we shall adopt
in the sampling and analyses of wastes collected from the Enemalta Chimney. The first step
is the development of a Sampling Plan:
Define the Sampling Plan.
Take the sample in accordance with the Sampling Plan.
Transport the sample to the laboratory.
Prepare the test portion.
Extraction of solid sample.
Analyse the sample.
Produce the overall report.
The most likely solid residues (i.e. ash) formed by incineration at the Enemalta Chimney are
likely to include:
IBA (Incinerator bottom ash).
Furnace bottom ash (FBA).
Pulverised fuel ash (PFA).
EN 14899 ensures that samples of solid residues taken for analysis:
are collected in a traceable manner,
6.3.2 are taken as representatively as possible to minimise sampling bias,
6.3.3 sample treatment is consistent to ensure analytical results can be compared
6.4
According to EN 14899 – 2005, the steps to develop a sampling plan for a thermal
processing chimney plant such as the one at the Marsa Power Station, are the following:
6.4.1 Procedures for sample preservation, packaging, transport and delivery
6.4.1.1
Sampling and sub-sampling techniques
6.4.1.2
Identify.
6.4.1.2.1 Sampling population: subject to the chimney height as well as the thickness of the ash
deposits, one representative sample shall be collected from the sides of the chimney,
going down as the dismantling progresses.
a. Number of samples: estimated 12.
b. Sampling pattern, location: representative from sides of chimney.
c. Sample size: one litre.
d. Required reliability of sampling results: Representativeness for the length of the
chimney. The samples shall then be mixed to generate one single representative
sample. According to EN 14899, one sample should be enough for wastes less than
100 tonnes.
6.4.1.3
Define:
6.4.1.3.1 Location of material to be sampled: sides of chimney.
6.4.1.3.2 Production process: disused.
6.4.1.3.3 Variability of process: should vary at the bottom part of chimney
6.4.1.3.4 Ash characteristics: light deposits with some caked residues.
6.4.1.4
6.4.1.4.1
6.4.1.4.2
6.4.1.4.3
Selecting constituent to be studied
Physical: need to identify the EWC according to LN 337 of 2001.
Chemical: waste must be characterised according to Directive 2003/33/EC
Biological: not applicable.
Basic characterisation
Compliance testing
On site verification
LN 337 of 2001
Directive 2003/33/EC
The EWC for the ash that can be found at the Enemalta chimney is likely to consist of the following
EWC codes:
Chapter 10 WASTES FROM THERMAL PROCESSES
10 01 wastes from power stations and other combustion plants (except 19)
10 01 01 bottom ash, slag and boiler dust (excluding boiler dust mentioned in 10 01 04)
10 01 02 coal fly ash
10 01 03 peat and untreated wood fly ash
10 01 04* oil fly ash and boiler dust
10 01 05 calcium-based reaction waste from flue gas desulphurisation in solid form
10 01 07 calcium-based reaction waste from flue gas desulphurisation in sludge form
10 01 09* sulphuric acid
10 01 13* fly ash from emulsified hydrocarbons used as fuel
10 01 14* bottom ash, slag and boiler dust from co-incineration containing dangerous substances
10 01 15 bottom ash, slag and boiler dust from co-incineration other than those mentioned in 10 01
14
ENEMALTA CHIMNEY ASH SAMPLING RECORD (ADOPTED FROM
ANNEX A BS EN 14899:2005) SAMPLING RECORD
Sampling Plan reference:
Sample Code: (Reflect site location, material type
and date of collection)
Date and time of sampling:
Signature of Sampler:
Other persons present:
GENERAL INFORMATION
Client (company):
Waste Producer:
Contact:
Location of sampling:
Contact:
Carried out by
(company):
Sampler:
MATERIAL
Estimate of moisture
content:
Type of Material:
Description:(colour, odour, consistency/
homogeneity/ grain size – uniform or diverse)
SAMPLING METHODOLOGY
Describe/ define batch or consignment
sampled:
Place and point of sampling:
Access problems that affected areas or
volumes of material sampled:
Safety measures taken:
Procedure (describe procedure adopted):
Equipment used:
Number of increments/samples collected:*
Increment size/sample size:*
Observations during sampling:
Details of on-site determinations: (if undertaken
complete field record sheet and append to Sampling
Record)
SUB-SAMPLING & PRE-TREATMENT
Identify location: e.g. on-site or fixed laboratory
facility (describe whether open air or enclosed)
Procedure:
PACKAGING, PRESERVATION, STORAGE AND TRANSPORT DETAILS
Packaging:
Preservation:
Storage:
Transport:
DEVIATIONS FROM SAMPLING PLAN
Detail:
DELIVERY TO ANALYTICAL LABORATORY
Company: Delivery Date:
Received by:
Signature:
DR GEORGE PEPLOW
FEBRUARY 2015