A respirator covers your nose and mouth or your entire face and head to keep contaminated air out
of your respiratory system. Respirators range from disposable paper masks to self-contained breathing apparatus with full face mask and air cylinder. When respiratory protection is required in construction, we need to make sure we use the right type.
There are two basic types of a respirator:
- air purifying
- supplied air.
Air-Purifying Respirators
Air-purifying respirators do exactly what the name implies. They purify and filter the air before you breathe it in.
They do not supply air or oxygen. They can only purify air in the surrounding atmosphere. If oxygen
content in the surrounding air is less than 19%, this respirator can’t help you. There are different air-purifying filters for different hazards.
As always, we have to match the protection to the hazard. The hazard may be dust from concrete
cutting or dust from asbestos removal. It may be mist from spraying latex paint or vapour from spraying oil-based paint.
Each of these hazards may require a different air-purifying mask, filter, or cartridge. There is no all-purpose air-purifying respirator. If you’re welding coated metals in a confined space,
for example, an air-purifying respirator won’t protect you. You’ll need a supplied-air respirator.
Supplied-Air Respirators
A supplied-air respirator does exactly that. It supplies air. The air comes from a cylinder or a compressor. These respirators provide the best protection against many hazards. But they have their
limitations. With self-contained breathing apparatus, there are problems with weight and the limited
supply of air. With airline units, the trailing hose can get snagged or tangled.
There are also concerns with the quality of air stored in cylinders or supplied by compressors. It may not be the clean breathable air we need.
Remember – respirators are the last line of defence. When engineering controls or ventilation cannot
eliminate airborne contaminants, then we resort to air-purifying or supplied-air respirators.
To protect us, the respirator must be
- suited to the hazard
- properly fitted
- worn correctly
- properly maintained.
Use only approved respirators. The National Institute for Occupational Safety and Health (NIOSH) is a U.S. agency that approves respirators.
Wear NIOSH-approved respirators. Look for NIOSH approval numbers on cartridges.
SAFETY TALKS
Respirators
To provide protection, respirators must fit properly. Unfortunately, one size does not fit all. Most manufacturers offer three different sizes of facepieces, for instance. In some cases, no size from
one manufacturer may fit a worker and a different brand may be necessary. Even the most expensive respirator won’t protect you if it doesn’t fit right. You must make sure that your respirator doesn’t leak or slip. Fit must be tested every time you put on the respirator and throughout your shift.
Two easy tests can show whether most reusable respirators fit properly and do not leak:
• negative pressure test
• positive pressure test.
Negative Pressure Test
- Put on the facepiece and adjust it to fit comfortably – snug, not overly tight.
- Block the air inlets. These are usually the filter openings on the sides of the facepiece.
- Try to breathe in.
- If there are no leaks, the facepiece should collapse slightly and stay like that while you hold
- your breath for 10 seconds.
Positive Pressure Test
- Put on the facepiece and adjust it to fit comfortably – snug, not overly tight.
- Block the exhalation valve. This is usually on the bottom of the respirator.
- Try to breathe out.
- The facepiece should puff slightly away from your face and stay like that while you hold your breath
- for 10 seconds.
Either test will detect significant leaks. If you find a leak, adjust the facepiece or straps and
repeat the test until you get a good fit. Test periodically while you’re wearing the respirator.Your respirator may get nudged or bumped out of position while you’re working.
Remember – the protection is only as good as the fit.
SAFETY TALKS
Respirators
Respirators are like other tools. They need maintenance to work properly. The job your respirator does is pretty important. So let’s make sure that all the parts are there and working right. We should check filters, valves, straps, buckles, and facepiece.
Filters
Filters are classified by a letter and a number.
The letters are
N – not resistant to oil
R – resistant to oil
P – oil-proof.
The numbers are 95, 99, and 100. These measure efficiency: 95 (95%), 99 (99%), and 100 (99.97%).
With use, filters become harder to breathe through. You’re breathing not only through the filter but also through the layers of contaminants that build up on the outside of the filter. Change filters whenever
- the filter is damaged
- the filter becomes difficult to breathe through.
As gas and organic vapour filters are used, their ability to remove gases and vapours decreases.
They must be replaced according to a pre-set schedule determined by the manufacturer.
Leave the contaminated area and change filters right away if
- - you can smell or taste the contaminant through the filter
- - your throat or lungs feel irritated.
Valves
Damaged, missing, or poorly seated valves can drastically reduce the protection provided by your
respirator.
Check the inhalation valves.
Remove filters and make sure the flapper valve (usually a flexible disk) is not missing or damaged.
Make sure that it’s seated properly in the valve assembly. To inspect the exhalation valve, remove the cover at the bottom of the respirator. Check the valve for damage and proper seating. Straps and Buckles Make sure that straps and buckles are free of damage and function properly. Facepiece
Check for holes, cracks, and splits. Don’t share respirators. It’s not hygienic. [With the crew, inspect respirators in use. Make necessary adjustments, repairs, or replacements.]
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