Welding 10
Outcomes:
1. Identify the purpose and the proper use of personal protective equipment
(PPE) used to protect a welder’s eyes.
2. Identify the hazards, which can cause eye injuries in individuals working in
the welding trade.
Personal Protective Equipment (PPE)
Eye Protection
One quarter of all injuries sustained by
welders are eye injuries.
Eye protection is very important when working around welding and cutting operations.
Everyone who is in the area of welding and thermal cutting processes needs protection
from radiant energy, sparks, slag and other debris. All individuals who enter an area
where sparks, slag, flying particles and hazardous light rays are present, must wear eye
protection, from the moment they enter the worksite, until they leave the worksite.
The various types of eye protection are broken down into classes in the Canadian
Standards Association (CSA) standard Z94.3.1 "Selection, use, and care of protective
eyewear". Each class has a specific use that it has been designed for. Eye protection for
welding and cutting operations can include:
safety glasses,
full-face visor or clear plastic goggles,
welding goggles and
welding helmet.
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The Electromagnetic Spectrum
During welding processes, the energy required to melt the metal must be concentrated
within the arc stream the energy within the stream is released as radiation. This
radiation given off by the arc is characterized by wavelength, which is called the
electromagnetic spectrum.
Electromagnetic spectrum of the welding arc: The welding arc produces mainly the following three types of radiation:
Ultraviolet (UVB) and 280-315 nm (UVA) 315 to 400 nm
Visible: 400 to 770 nm
Infrared (IR) 770 to 1000 nm
The radiation released from the arc can
caused burns to the eyes and exposed
skin and over time Ultra Violet light rays
can cause skin cancer.
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Effect of light rays on the eyes
Welders Flash (Arc Burn)
For welders the main effect of light radiation, on the eyes, is called the arc flash or
"welder's flash", which is a photochemical damage of the cornea (photokeratitis) due to
Ultraviolet light (UV) and to the blue portion of visible light (400-500 nm). This type of
damage may also reach the conjunctiva of the eye (white of the eye). The radiation of
the visible and Infra Red (IR) part of the spectrum causes headaches, and after repeated
long exposure, cataracts may form.
Cataracts
Safety standards for welding require an almost complete protection in the UV
wavelengths (spectral transmission <0.002%) between 210 and 330 nm and a very
strong one (spectral transmittance of <3%) for radiation from 313 to 400 nm. For
radiation of longer wavelength, it establishes a G risk factor.
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Safety Glasses
You should always wear safety glasses in a welding environment to protect you
from arc flash, sparks and flying particles. They should have side shields and be shatter
resistant.
They may be tinted, depending on the
particular environment you work in
and the level of protection you need.
If tinted, safety glasses usually have a
#1 or #2 shade and should be worn
when you have to work near others
who are using an arc welding process.
Tinted safety glasses are designed to
protect individuals from the
occasional exposure to the arc flash.
Prescription safety glasses are
available and many styles have side
shields that can be clipped on when you work in the shop. Safety glasses should fit
under all face protection equipment.
Full-Face Visor
Your entire face should be protected by a full-face visor and should be used in
conjunction with safety glasses
when performing operations such
as grinding or chipping. It should
fit over your safety glasses. If you
are wearing clear safety glasses
and are using a CSA Z94.3-certified
face shield for oxy-fuel welding or
cutting, it should have a #4 or #5
shade or higher, depending on the
job.
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Welding Goggles
Welding goggles are worn when oxy-fuel welding or cutting to filter out the
harmful light rays and to prevent slag and sparks from entering the eyes. Filter plates
are available in various shades depending on the intensity of the light radiation in the
welding or cutting environment. Usually, a shade #4 or #5 is adequate for light cutting
and welding. You may want to use a darker shade for heavier cutting and welding.
As a general rule, if after cutting or welding for a few minutes, if you lift your
goggles or helmet and see
light spots, your lens is
probably too light. If you see
dark spots, your lens is likely
too dark. Everyone's eyes have
a different level of sensitivity
to light. Therefore, the shade
filter plate to use is ultimately
up to you. Just make sure you
can see clearly so you can
watch for correct metal flow,
and placement.
Arc Welding Helmets and
Filter Plates
A suitable welding helmet must be worn when welding or grinding to protect
your eyes and facial area from harmful rays and flying particles. The helmet shell
protects your face from light, heat, spatter and slag. Helmets are available with flip
fronts, fixed fronts or photoelectric filter systems. The flip front or photoelectric type is
best for general welding operations because it
provides continuous protection while you inspect
the weld and chip the slag with your helmet in front
of your face. If a hard hat is required, a welding
helmet can be attached to your hard hat with a
special swivel attachment
Special filter plates (sometimes called filter
lenses) for welding operations are available in
various shades
ranging from #1
(lightest) to #14.
The filter plate absorbs most of the harmful
ultraviolet and infrared rays, as well as a large
amount of visible light. The dark glass is only a filter
and in no way does anything to correct vision
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problems. A suitable choice shade for your particular welding process has a considerable
effect on your comfort and vision. The objective is to select a shade that eliminates
glare, but allows you to see the work distinctly. Therefore, no one shade of filter plate
will suit all types of welding and cutting operations. The type of filter plate used for
most welding and cutting is a hardened blue/green glass. Both the American Welding
Society (AWS) and the Canadian Standards Association (CSA) have guidelines for filter
plates for most welding and cutting operations.
Shade Numbers for Welding and Cutting Operations (from CSA W117.2)
Process
Light Duty Cutting
Medium Duty Cutting
Heavy Duty Cutting
Light Gas Welding and
Brazing
SMAW
GMAW, FCAW
Air Carbon Arc Cutting
Minimum Shade #
3
4
5
3
Suggested Shade #
4
5
6
4-5
8
10
10 - 11
10
11 - 14
12 - 14
Welding helmets have an opening through which welders can safely view the welding
arc. The welder’s eyes are protected by a series of plastic plates. Theses plastic plates
protect your face when you are chipping slag or inspecting welds. Mount the coloured
plate between two pieces of clear glass or plastic in the helmet visor to protect the filter
plate from weld spatter. A gasket should be placed between the outer clear glass or
plastic and the filter plate. This gasket provides an air space between the two plates,
which helps prevent heat cracking of the filter plate and also separates the plates so
moisture build-up does not cloud your vision. Some helmet flip fronts may only have
room for the outside clear plate, the gasket and the filter plate.
Review Questions
1. How common are eye injuries amongst individuals who work in the welding
trade?
2. In what ways does eye protection protect a welder?
3. When must eye protection be worn?
4. How do the light rays, which are given off the arc welder, affect the welder’s
eyes?
5. What is a cataract and what causes them?
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6. What shade number may be used as protection against occasional arc flash?
7. When using a grinder what additional protection is required?
8. What shade-number of safety glasses are required for oxy-fuel cutting or
welding?
9. What shade-number of safety glasses are required for arc welding?
10. Why does a welding helmet have a clear plastic plate mounted in the helmet?
11. Why is the consistent use of eye protection important?
12. Welders are exposed to hazards, which are unique to the welding trade.
Compare the how the eye protection requirements for welders, compares to
the eye protection requirements for other trades.
13. Why are welding safety glasses tinted?
14. Under what circumstances would a welder require a face shield in addition to
eye protection?
15. Arc welding helmets may be used with a wide range of shade numbers. Using
examples, which involve arc welding, describe when it would be acceptable
for a welder to use a shade number from the bottom of the scale and when a
welder would use a shade number from the top of the scale.
Resources
Welding - Personal Protective Equipment and Clothing
Safety in Welding, Cutting, and Allied Processes
ILM Welding – Welding Safety 120101cp6.2.docx
https://tradesecrets.alberta.ca/ILMOrder/order.html
Alberta trades schools, in conjunction with the government of Alberta have
produced a series of educational booklets for most trades. These booklets
are called Individual Learning modules (ILM). These Modules have are used
by high schools and trade schools across Canada.
http://supporting-paa.wikispaces.com/Personal+Protective+Equipment
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http://ohsonline.com/articles/2007/02/preventing-eye-injuries-when-welding.aspx
Canadian Standards Association (CSA) standard Z94.3.1 - Selection, use, and care of
protective eyewear
A recent survey found that three out of five workers suffering eye injuries wore
no eye protection. Half of those who did use safety eyewear wore the wrong
type. To be effective, eye protection must be properly selected for the job and
fitted to the wearer. Note: CAN/CSA-Z94.3 requires that only qualified
professionals are required to fit prescription safety eyewear (e.g., a licensed
ophthalmic practitioner). The first choice in preventing eye injuries is to design
work procedures and equipment so that workers are not exposed to eye
hazards. However, the total elimination of eye hazards from the workplace is
often not possible, and other measures must be taken to control residual
hazards so that they do not result in injuries to workers and others in the work
zone. One such control measure is the wearing of personal protective equipment
(such as protective eyewear). It is well recognized that wearing appropriate
protective eyewear and following basic safety rules can prevent the majority of
eye injuries. The purpose of this user's guide is to provide advice for the proper
selection of eye protection in relation to the specific hazardous activity involved;
not all hazards have been identified in this guide. Any well-designed eye and face
protection program should be part of an effective occupational health and safety
management system. Specifications for such a management system can be
found in CAN/CSA-Z1000, Occupational Health and Safety Management. This
Standard is based on the Plan-Do-Check-Act model of safety management, and it
lays out the basis for proper management of personal protective equipment as a
necessary strategy for injury and illness prevention.
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product support question about our many products and services, the Canadian Centre for
Occupational Health and Safety (CCOHS) Inquiries and Client Services team is dedicated to answering
any questions you may have. Use this link to get connected with a health and safety expert.
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