Classification of filters and absorbers

Filters and removable absorbers for masks and half masks (* Letter symbols and color codes used to mark filters and absorbers depending on their purpose):

• A - brown - organic gases and vapors with a boiling point above 65 ° C
• AX - brown - organic gases and vapors with a boiling point below 65 ° C
• B - gray - inorganic gases and vapors, except for carbon monoxide,
• E - yellow - acid gases and vapors, e.g. sulfur dioxide
• K - green - ammonia and organic ammonia derivatives
• SX - violet - substances specified by the manufacturer, the so-called special absorber
• NO - blue - nitrogen oxides
• Hg - red - mercury vapor
• P - white - liquid dusts and aerosols

Classification of gas absorbers

• class 1 - filters with low sorption capacity, intended for protection against gases or vapors with a volumetric concentration in the air not exceeding 0.1% (1,000 ppm),
• class 2 - absorbers with medium sorption capacity, intended for protection against gases or vapors with a volumetric concentration in the air not exceeding 0.5% (5.000 ppm),
• class 3 - absorbers with high sorption capacity, designed to protect against gases or vapors with a volumetric concentration in the air of up to 1% (10,000 ppm).
• Division of filters

Sodium chloride and paraffin oil mist determine the appropriate filtration efficiency, thanks to which we can distinguish three classes of filters:

• class 1 - (P1) - filtration efficiency 80% - used for protection against low toxicity solid particles for which NDS≥2mg / m3,
• class 2 - (P2) - filtration efficiency 94% - used for protection against solid and liquid particles of low and medium toxicity, for which NDS≥0.05mg / m3,
• class 3 - (P3) - filtration efficiency 99.95% - used for protection against highly toxic solid and liquid particles for which TLV <0.05mg / m3.
• Filtering half masks

We distinguish three classes of protection depending on the effectiveness of filtering:

• class 1 - (FFP1) - filtration efficiency 80% - used for protection against low toxicity solid and liquid particles for which NDS≥2mg / m3, provided that the maximum concentration is up to 4x NDS,
• class 2 - (FFP2) - filtration efficiency 94% - used to protect against solid and liquid particles of low and medium toxicity for which NDS≥0.05mg / m3, provided that the maximum concentration is up to 10x NDS,
• class 3 - (FFP3) - filtration efficiency 97% - used to protect against highly toxic solid and liquid particles for which TLV <0.05mg / m3, provided that the maximum concentration is up to 20x TLV.

Additional markings of filtering half masks:

• C - additional requirement of adequate dust absorption, checked with coal dust,
• D - additional requirement of adequate dust absorption, checked with dolomite dust,
• S - half mask designed to filter only solid particles (dust, smoke),
• SL - half mask designed for the filtration of solid particles (dust, smoke) and liquid particles (fog).