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 ?
ese gas masks shouldn't be worn today as they contain asbestos.
In Britain around 25 million military gas masks - also known as "General Service Respirators (GSR)" were manufactured between 1935 and 1942.
Gas masks offer the best protection from the inhalation of toxic gases and pollutants as they cover the nose and mouth, and in many cases the eyes.
They were nicknamed Mickey Mouse gas masks to make them less scary for youngsters and there were daily drills in school on how to wear them.
Manufactured gas masks use specialized filters to trap or neutralize harmful chemical compounds.
Stuart said: "The gas masks are in very good condition and look as if they were handed out just a few days ago.
for Disposable Anesthesia Gas Masks by Geographic Region - US,
MEMORIES: Clockwise, from left, some of the village's older folks speaking about their experiences during the Second World War; some of the pupils looking at gas masks and helmets; David Edwards, 76, talks to the youngsters and Joan Kenning, 93, talking about life during the war.
We were issued with gas masks and had to carry them to school every day.
Prosecutors claim he stole Ministry of Defence helmets, ration packs, tyres and gas masks while stationed at Albemarle barracks, in Northumberland, then sold them on eBay to ease his debts.
5, 2010 decided to distribute eight million new gas masks, one for each citizen, by 2013 and already distributed gas masks to 70,000 residents of Or Yehuda, near Tel Aviv in February.
Israel has begun distributing new gas masks to its 7 million citizens to offer protection against a possible chemical attack, the Associated Press reported Monday.