Classification of filters for masks: regulations, colors and durability


Any type of industrial or artisan activity produces micro pollutants that disperse into the environment and with which we come into contact, whether they are more or less dangerous for our body.

When we use respiratory protection devices , also called respiratory protection devices , we need to know the classification of the filters for masks in order to be able to choose the APRV suitable for that particular context.

The colors of the mask filters , in accordance with provide a fast and safe method to ensure that the filter you are using is the right one.

Filter respirators with full face mask or filter holder half mask and filter insert

In situations and work environments where the atmosphere can be polluted by gases and vapors, these devices are used, combined with gas filters or dust filters personal safety equipment masks.

The half masks are reusable devices that cover the nose, mouth and chin, equipped with an exhalation valve. They can be made of silicone or rubber. One or more replaceable filters are applied to the half-masks, depending on the type of pollutant from which they must be preserved.

The full face masks are devices that cover the entire face, equipped with a transparent visor and an exhalation valve. They guarantee a better seal than the half-masks, protecting both the respiratory tract and the eyes, and are reusable.

Types of pollutants for the respiratory tract

Contaminants are divided as follows:

  • Powders : fine particles generated by the crushing of solid materials
  • Mists : tiny organic or water-based liquid droplets that are created by spraying operations.
  • Fumes : very fine solid particles, formed when melting or vaporizing a metal that cools down quickly.
  • Gas : substances in the aeriform state at pressure and at room temperature.
  • Vapors : gaseous form of substances which, at room temperature, are in a liquid or solid state.

Mask filters categories

The filters inserted on the masks and half-masks and are intended to retain solid or aeriform pollutants. The color of the mask filters serves to differentiate them and to specify the category of belonging: each color used in the coloring of the bands refers to the specific pollutant it removes.

  • TYPE P filter , WHITE color : it is the filter used for dusts, solid aerosols and toxic liquids.
  • TYPE A filter , BROWN color : it is used for certain organic gases or vapors with a boiling point above 65 °, solvents and hydrocarbons (acetates, acids, acrylate, alcohol, benzene, ethanol, white spirit). In the case of organic gases and vapors with a boiling point less than or equal to 65 ° (methyl acetate, acetone, butane, chloroform, methanol) the color is always brown but the type of filter is called AX .
  • Type B filter , GRAY color : to be used for certain inorganic gases and vapors (acids, bromine, cyanide, chlorine dioxide, fluorine, carbon disulphide) excluding carbon monoxide (CO).
  • TYPE E filter , YELLOW color : used for acids, sulfur dioxide (or sulfur dioxide, SO2) and hydrochloric acid.
  • TYPE K filter , GREEN color : to be used for ammonia and organic ammonia derivatives (aziridine, butyl amine, hydrazine, methylamine).
  • CO TYPE filter , BLACK color : used for carbon monoxide.
  • TYPE Reactor , ORANGE color : used for iodine.
  • TYPE NO-P3 , BLUE-WHITE color : it is used for nitrogen oxides and nitrous vapor. It also protects against dust.
  • TYPE Hg-P3 , RED-WHITE color : used for mercury vapors. It also protects against dust.

ABEK filters are in turn classified according to their filtering capacity:

  • Class 1 : low capacity (gas content less than 1,000 ppm)
  • Class 2 : medium capacity (gas content less than 5,000 ppm)
  • Class 3 : high capacity (gas content less than 10,000 ppm)

Combined filters

The combined filters combine different types of mask filters (ABEK), guaranteeing all the requirements prescribed separately for each type of filter. Consequently they have all the identifying colors of the corresponding filters . For example: an ABEK2P3 filter must be identified with the colors brown, gray, yellow, green and white.

Duration of mask filters

The life of the filter depends on the class and type of use : the humidity and temperature of the inspired air, the consumption of air by the user and the concentrations and combinations of toxic contaminants influence the life of the filter in various ways . Normally the breakage of the filter occurs with the perception of odors by the user: in this case proceed immediately with the replacement of the mask filters.

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