Many filter cartridges also do not filter combustion gasses like carbon monoxide. Thanks to charliemeyer007 for reminding me of this important caveat to respirator use. Remember, respirators do not provide you with oxygen, and will not protect you from environments where the oxygen has been depleted or displaced by other gasses. Keep in mind that the filter will become “hazardous” as you use it, so use caution when removing your mask or changing cartridges to prevent self-contamination. Instead, it is recommended that “All filters should be replaced whenever they are damaged, soiled, or causing noticeably increased breathing resistance (e.g., causing discomfort to the wearer).” How long that takes depends on how much “dust” is in the air. Because of this, particulate filters don’t have an established service life. The particulates become trapped on or in the filter medium. Using a particulate filter (N95, N99, R99, P100, etc) in these environments doesn’t degrade the filter in the manner that a chemical environment degrades a filter. CS (Tear Gas), radioactive fallout (radioactive vapors and gasses excepted) and biological agents are all classified as particulates. Since some threats are odorless/tasteless at dangerous concentrations or may otherwise damage the sense of smell, you cannot rely on your sense of smell to tell you when you need a new filter.įortunately, most of the CBRN equation is composed of particulate agents. Under high concentrations, the agent will break through the filter medium much faster than the times referenced above. As with other hazardous chemicals, how well and how long a filter performs against chemical warfare agents is based on the agent and the concentration of that agent. Note, that this doesn’t mean a respirator filter will last the full 8 hours, or even the full 2 hours. If the respirator is exposed to liquid droplets, that time drops to two (2) hours. The NIOSH CBRN Respiratory Protection Handbook recommends that NIOSH approved APRs (Air Purifying Respirators) be used for no longer than 8 hours once exposure to chemical warfare agents has started. It’s also why virtually every guide, standard, or manual recommends the use of SCBA when the agent or concentration is not known. This is the number one reason laypersons should only use gas masks and respirators for escape. If you’re unable to determine the concentration, there’s no way to determine how long the filter can be expected to provide adequate protection. It is highly unlikely a layperson will have access to the necessary tools or information to make an accurate measurement or estimate of the concentration. In the professional world, the service life of respirator cartridges/filters is based on the concentration of the agent being filtered. There are no “rules of thumb” for how long a layperson can use a respirator in an emergency setting. How long a filter cartridge will last is a complex problem and if you’re looking for a short, definitive answer, I’m afraid there isn’t one. Once exposed to air, these materials degrade and lose their protective properties. Those materials may be in a separate layer in the canister, or the activated charcoal may be impregnated with these catalysts. These filters also contain catalytic materials that react with some chemical vapors to neutralize them. Contrary to popular opinion, gas mask filters are not simply activated charcoal sandwiched by filter medium. If the filters are surplus filters without an expiration date or the filters are not sealed in the original manufacturer's air-tight container or packaging, regardless of what the seller claims, they should be treated as “expired”.Īfter the expiration date, or if they are opened for any reason, the filters should be discarded and replaced. Beware of companies claiming 20+ year shelf-lives, especially if the filter isn’t vacuum sealed. This may be 1 year, 5 years, 10 years or even longer. Provided they are properly sealed, the filters are good until the expiration printed on the packaging. Are the filters any good? How long will the filter last if I need to use it? QUESTION: I just bought a respirator/gas mask.
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