Features of filtering and absorbing boxes

The basics of chemical protection are compulsorily considered in the framework of school and university courses on life and labor protection. But not every one of us will remember the device and rules for using a gas mask after graduation. Therefore, for your own safety it is worth considering the main features of filter-absorbing boxes and the current rules for their labeling, depending on the purpose.

Filter-absorbing box for gas masks It is a cylindrical protective device that is attached to a connecting tube (a corrugated hose connected to a rubber mask). These devices are designed for direct filtration of the incoming gas mask from the external environment from harmful impurities: gaseous poisons, dust, radioactive substances, dangerous bacteria and other gases, aerosols and vapors that threaten human life and health.

In most models, the absorber is divided into two segments, namely: anti-aerosol and anti-dust... Activated carbon, hopcalite, aerosol filters, cotton wool and special absorbing materials are used as filtering materials, depending on the brand of the box. Usually a layer of activated carbon is present in all models, regardless of their purpose. It is always located at the very top, playing the role of the last protective barrier. Between the layers of the absorbing charge, there are grids separating them.

The upper (closest to the tube) mesh is additionally equipped with a layer of tampon cardboard, which prevents activated carbon dust from entering the respiratory system of a person using a gas mask.

Currently, on free sale and in warehouses, you can find gas masks and accessories for them, marked according to two different standards.

Let's consider both of these classifications in more detail.

According to the marking adopted in the EU countries, the filter boxes of industrial gas masks are of the following types:

• A (brown) - designed to filter vapors of substances boiling at temperatures below 65 ° C, as well as gases of organic origin;
• AX (brown) - this mixture provides filtration of vapors of substances with a boiling point of more than 65 ° C;
• B (gray) - provides air purification from most inorganic gases (with the exception of carbon monoxide);
• E (yellow) - used to protect against acid vapors and gases;
• CO (purple) - special grade for protection against carbon monoxide (carbon monoxide);
• K (green) - filters ammonia;
• NO (blue) - the filler consists of substances that remove nitrogen oxides;
• P (white) - designed for biological protection against aerosols of viruses and bacteria suspended in the air;
• Hg (red) - protects against mercury vapor and its hazardous compounds;
• SX (purple) - Provides protection against chemical weapons of mass destruction;
• Reactor (orange) - protects against radioactive isotopes of iodine and their compounds, and also reduces the amount of alpha particles entering the respiratory system.

In the USSR, GOST 12.4.235-2012 established the following brands of boxes:

• A (brown) - the technical characteristics of the filler of such boxes allowed them to purify the air from vapors of kerosene and gasoline, acetone, benzene, toluene, xylene, various alcohols and ethers, aniline, tetraethyl lead, organochlorine and organophosphorus compounds, nitrogen-containing aromatic substances and organohalogen substances;
• B (yellow marking) - protects against chlorine, sulfur dioxide, hydrogen chloride, hydrogen sulfide, phosgene, hydrogen cyanide and nitrogen oxides;
• Г (marked with a combination of black and yellow colors) - used to filter mercury vapors;
• KD (gray) - protects against ammonia, hydrogen sulfide and mixtures containing these substances;
• E (black) - used to filter gaseous phosphorus and arsenic hydrides;
• M (red) - a semi-universal option that provides sufficient protection against carbon monoxide (which may contain minor impurities of organic substances), ammonia, gases of acid origin, phosphorus and arsenic hydrides;
• CO (white) - a special grade of boxes for protection against carbon monoxide;
• BKF (the box is marked with a vertical white stripe) is another semi-universal model that provides protection against gases of acid origin, organic vapors, aerosols of solid substances, arsenic hydrides and gaseous phosphorus.

The presence of a filter is indicated by a vertical white stripe or a white bottom. Such boxes are used together with outdated models of gas masks (for example, GP-5) and may not fit newer versions, on the valve boxes and hoses of which a different design of the connecting unit can be used.

When purchasing gas masks and accessories for them, it is worth first of all pay attention to their expiration date. Even such reliable devices tend to fail, especially after long-term storage in unsuitable conditions. Saturated with dust and impurities from the surrounding storage air, fillers largely lose their filtering properties. In addition, an important role in the activity of absorption of impurities is played by state of the charge - the larger the specific surface of its particles, the more actively it will filter the air. The charge that has accumulated after long-term storage will not only become a bad filter, but also significantly complicate the passage of air through the box.

Choosing between different brands of boxes, consider the most likely emergencies at your facility... For example, if an ammonia pipeline passes nearby, then the most suitable brand of boxes for you will be K (according to the EU classification) or CD (according to the Soviet standard), and if you purchase gas masks for a warehouse where mercury is stored, then you need to purchase Hg brand boxes in a new or G by old standards.

See below for what is inside the filter box.