gas mask

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gas mask,

face covering or device used to protect the wearer from injurious gases and other noxious materials by filtering and purifying inhaled air. In addition to military use (see chemical warfarechemical warfare,
employment in war of incendiaries, poison gases, and other chemical substances. Ancient armies attacking or defending fortified cities threw burning oil and fireballs. A primitive type of flamethrower was employed as early as the 5th cent. B.C.
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), gas masks are employed in mining, in industrial chemistry, and by firemen and rescue squads. The gas mask consists essentially of a face cover with two eyepieces and a mouthpiece that communicates with a canister containing a filter. The filter absorbs noxious gases as they pass through the canister to the mouth. The face cover also has a one-way outlet valve for exhaled air. See poison gaspoison gas,
any of various gases sometimes used in warfare or riot control because of their poisonous or corrosive nature. These gases may be roughly grouped according to the portal of entry into the body and their physiological effects.
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Gas Mask


a device for protecting the respiratory organs, eyes, and face of a person against toxic and radioactive substances, bacterial agents, and other harmful impurities in the air in the form of vapors, gases, or aerosols. Gas masks are classified by their method of protection as filtering masks, whose action is based on decontamination or filtration of harmful impurities from the air inspired, and oxygen masks, which completely isolate the respiratory organs from the environment (the air breathed is regenerated in the cartridge of the gas mask).

Filtration gas masks in the form of multilayered gauze bandages soaked with special solutions for protection against chlorine and phosgene appeared during World War I, but they were not effective against other toxic agents. In 1915 the Russian chemist N. D. Zelinskii invented the world’s first dry filtering gas mask with activated charcoal and a rubber mask. In 1916 this gas mask was adopted by the Russian and Allied armies. Dry gas masks soon appeared in the armies of other countries. The present-day filtering gas mask consists of a canister, a facepiece (helmet), and a carrier (pouch). As it is inspired, the contaminated air enters the canister. Aerosols are removed in the aerosol filter, and vapors and gases are removed in the layer (chemical absorber) of activated charcoal. The air decontaminated in the canister passes through the connecting tube under the facepiece of the mask. The facepiece consists of a rubber helmet-mask with goggles and a valve unit. The gas mask set includes means to prevent the goggles from steaming up (a special pencil and an antisweat film). In the winter, insulating packing is mounted on the eyepiece rings of the helmet-mask. The mask can be used for an extended period of time and weighs about 2 kg.

Isolation-type oxygen masks are used in cases where filtering masks do not provide protection, for example, where there is a deficiency of oxygen in the environment. A distinction is made between oxygen masks based on the use of chemicals and those using compressed oxygen in containers. In the first kind, air that is exhaled enters the cartridge where water vapor and carbon dioxide are absorbed and oxygen is given off; the air then passes into the breathing bag. When inspired, the air passes again from the bag through the cartridge and enters at the bottom of the facepiece. The process is repeated for each breathing cycle. This kind of gas mask can be used from one to three hours and weighs 4–4.5 kg. In the isolation-type mask based on the use of compressed oxygen, when the exhaled air enters the cartridge the carbon dioxide is removed and the air passes into the breathing bag, to which oxygen from the bottle is fed simultaneously. When inspired, the oxygen-enriched air enters at the bottom of the facepiece of the mask. This kind of mask can be used for one or two hours and weighs roughly 9 kg.


gas mask

[′gas ‚mask]
A device to protect the eyes and respiratory tract from noxious gases, vapors, and aerosols, by removing contamination with a filter and a bed of adsorbent material.
References in periodicals archive ?
Jungle fighters and paratroopers used the M2 training gas mask instead of their M2 service gas masks due to the lighter weight and compactness.
A Sailor is fitted for new CBR suits, boots, gloves and a gas mask.
Arly also said he has been working as a miner for nine years but does not know how to use a gas mask.
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It was revealed Paul had been chatting on the internet while dressed in a rubber suit, gas mask and wellies.
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The Navy desired a gas mask to protect the user from chemical agents while working.
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The first army supply shop I tried had sold out and the man behind the counter was getting it in the neck from a 70-year-old lady who was screaming that she'd take her chances with bin Laden if he he was charging pounds 35 for a gas mask.
In December, the man who runs Seattle dreamed up the bright notion of gas mask control.
Klapheck's sewing machines, motorcycles, adding machines, and occasionally things less easily identified (The Party, 1992, depicts a gas mask of the type Israeli civilians used during the Gulf War) are rendered with great clarity of outline and volumetric concreteness, as though to flatter the eye's desire for something it can fully grasp, and yet they also take on a disturbing categorical opacity, an uncanny intimation that they merely disguise some other form of existence whose significance is completely inaccessible.