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There are two types of respirator:
1. Air-purifying respirators: providing a barrier between your respiratory system and the environment you are in, these include disposable, half-face, full-face particulate masks and powered air purifying respirators (papr).
2. Supplied air respirators: such as used by the fire service or in SCUBA diving.
AHAH only use air-purifying respirators in our daily work, to protect our workers against airborne contaminants.
To determine the appropriate respirator protection level, we must first understand the ratings and what the various components indicate.
Firstly, respirators are rated as N, R, or P for protection against oil based particles (such as fuel, lubricating or hydraulic oil, solvents, paints or pesticides).
N: if they are Not resistant to oil
R: if somewhat Resistant to oil
P: is strongly resistant to oil (oil Proof)
Next, is the rating of percentage of one-micrometer particles, removed during clinical trials.
95: a barrier against 95% of one-micrometer particles
99: a barrier against 99% of one-micrometer particles
100: a barrier against 99.97% of one-micrometer particles
We can now see that a P100 means that it is a mask rated to remove 99.97% of one-micrometer particles, even if they are oil based.
Disposable vs Reusable masks
Disposable masks share the same 9 factors (n,r,p & 95/97/100) as half, or full-face masks. The key here is that the mask should be disposed of, after each use.
Gas and vapors
In addition to air particles, we also need to consider gas and vapors contaminants. To protect against gas and vapors in the air.
Gas & vapors are removed from the air by using active carbon filters, typically in a cartridge form.
There are different types of cartridge depending on the type of gas or vapor you are trying to protect against. Different cartridges contain additional types of fiber to capture the substance. You can learn more in the links below.
3M guide to cartridges & filters:
https://multimedia.3m.com/mws/media/565214O/3m-cartridge-filter-guide-and-brochure.pdf
3M Respirator selection poster:
Choosing the correct respirator
Now you understand the options for respiratory protection, we must understand the hazard we are protecting against to determine the correct level of protection.
This requires research to identify the threats which may already exist in the environment (such as mold) and those hazards we introduce through our work (such as Shockwave). Always refer to manufacturers guidelines for safety information. Reach out to the HSS team if the guidance is not available or unclear.
You can also check out the Hazardous Substances section of the Portal for guides on PPE per substance.
Other types of classification
Australia and New Zealand have another classification system, which we may encounter in some parts of the world:
AS/NZS1716 uses a classification system to identify the different types of particulates these filters will capture e.g. P1, P2, P3.
P1 - Particles generated by mechanical processes e.g. grinding, sanding
P2 - Particles generated by mechanical and thermal processes e.g. welding
P3 - Particles including highly toxic materials
Disposal of respirators and components
Disposable masks: dispose after each use.
Half face & full face masks: remove cartridges, clean and store in dry environment for re-use. Dispose of when the plastic tears, cracks, or appears otherwise degraded.
Particulate filters: dispose of particulate filters when:
It becomes difficult to breathe comfortably (this will vary from individual to individual).
The filter becomes dirty or physical damage occurs.
When working in situations with oil based particulates: after 40 hours of use or 30 days, whichever is first.
Cartridge filters:
Cartridge replacement schedules are determined by a number of factors, including contaminant type, temperature, humidity and work rate of the user.
Dispose of cartridge filters when:
As soon as taste or smell of a containment is detected through a correctly fitted mask.
When the expiry date stamped on the sealed packet has elapsed.
Once opened, maximum use time is 6 months (even if not used). The carbon will absorb contaminants from the general environment.
You can use the 3M Service Life web-based software to determine the correct replacement schedule for your situation.
Or, use the rule-of-thumb of: after 40 hours of use or 30 days, whichever is first.
Fitting & testing respirators
Your respirator must fit you correctly if it is to function as intended. Fitting does depend on the type of mask, refer to the user instructions that come with the unit and ask for support if it is unclear.
Facial hair can prevent a suitable seal being established. People with beards, may not be able to get the protection of a respirator, unless they shave. Whilst we are not putting in place a "no beard, no work" rule, we do want every worker to make an informed decision.
For half face and full face respirators, we also recommend you perform a seal test each time you put the unit on. See the video to the right for details of how to perform a seal test.
Storage of Respirators
Keep your respirator clean and in good operating condition.
Check for dirt, cracks, tears or other damage before and after each use.
When you open a new cartridge, write the date on the cartridge, using a sharpie.
Disassemble your respirator before cleaning the faceplate in warm water. Use a disinfecting soap. Then thoroughly rinse it off.
Cartridges which have not yet reached the end of their usable life, should be stored in sealed zip lock style bags.
Store your respirator and cartridges in a cool, dry place away from chemicals and engine exhaust.
Common solutions used at AHAH
Below is a list of common tasks and the correct respiratory PPE for each. This can only be a guide and shoudl not replace a proper selection process, as we must assume a static environment. The dynamic environment we encounter and create, must be factored into decisions regarding PPE.
For instance, we may say that for a N-95 is fine for sanding, however, if someone is also applying Shockwave in the same vicinity we need to have protection against that chemical - as well as the dust.
Dust from sanding - n95 or higher (n/p/95/99/100)
Muck and gutting - p100 filter on a half face respirator or better (full face)
Mold sanitation - see the Mold section in Hazardous Substances
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