Gas mask filter codification
Gas filters
For each gas mask category and depending on the nature of gases or vapors, there are different gas mask filter types. Each respirator cartridge is labeled with a letter and a specific color for every gas or gas family in compliance with the EN 14687 European standard.
Gas mask filter respirator cartridge color codes:
A | Organic gas and vapor with boiling point above 65°C (solvents, hydrocarbons, alcohols, benzene, ethanol, refrigerants/freons, white spirit) | |
AX | Organic compound gas and vapor with boiling point below 65°C (many VOCs, methyl acetate, acetone, chloroform, methanol, phenol, styrene) | |
B | Inorganic gas and vapor (hydrocyanic acid, bromine, chlorine, cyanide, chlorine dioxide, fluorine, hydrogen sulfide, carbon disulfide) | |
CO | Carbon monoxide | |
E | Acid gas and vapor – mainly associated with P3 – (acrylic acid, formic acid, nitric acid, hydrogen chloride, sulfur dioxide, hydrogen fluoride) | |
Hg | Mercury vapor and derivatives – mainly associated with P3 | |
K | Ammonia and organic derivatives (DMA, DMEA, hydrazine, methylamine, MMH, UMDS) | |
Nox | Nitric oxide, nitrogen oxide, nitrous vapor | |
REACTOR | Radioactive iodine, radioactive methyl iodine | |
Sx | Specific manufacturer mentioned gas and vapor | |
P | Solid and liquid particles (lead, asbestos, ceramic fibers, aerosols), highly toxic and radioactive particles, bacteria and viruses (bird flu, A/H1N1 flue, SRAS, tuberculosis, Ebola virus) |
⇒ Find the proper respirator cartridge filter for your application
Gas mask filter categories:
According to the EN143 and EN143/A1 standards, air purifying respirator filters are gathered into efficiency categories.
Maximum toxic substances concentrations allowed:
– Half mask respirator: 50 times the OEL
– Full-face mask respirator: 2000 times the OEL
. Class 1 (lower efficiency): Canister filter (ex: A1) – small capacity, gas rate below 0,1% volume
. Class 2: Cartridge filter (ex: ABEK2) – intermediate capacity, gas rate below 0.5% volume
. Class 3: For a gas rate below 1% volume
Particles filter
For gas mask filters, there are different particles filter classes:
– P1 class filters – low efficiency, stop at least 80% of this aerosol (penetration below 20%)
– P2 class filters – intermediate efficiency, stop at least 94% of this aerosol (penetration below 6%)
– P3 class filters – high efficiency, stop at least 99,95% of this aerosol (penetration below 0,05%)
Combined filters (gas and particles)
As the name implies, a combined gas mask filter stop both gases and particles. These filtering respirator cartridges are heavier than aerosol or gas cartridges but are more efficient. Air enters first a particle filter (which is also a pre-filter) and then goes through a gas filter.
Combined gas and particles filters provide safety against paint droplets and gases as well. These respiratory protective cartridges are mainly used for liquid spraying works.
Filtering air purifying respirator usage limits
Never use filtering respiratory personal protective equipment in the following situations:
– Ambient oxygen rate below 19%
– In confined spaces or any poorly ventilated areas: tanks, tunnels, boat slips…
– When the substance concentration is unknown or immediately dangerous to life or health (IDLH)
– When the substance concentration exceeds the allowable concentration or the filter capacity
In these situations the use of atmosphere supplying respirators like SCBAs, supplied air respirator systems and emergency escape breathing devices is recommended