Gas Mask
A gas mask is a mask to be placed over the face to protect the wearer from inhaling
airborne pollutants and other toxic gases. The mask forms a sealed cover's the nose
and mouth, but may also cover the eyes and other parts of soft tissue that's part of
the face. Airborne toxic material are maybe in a gaseous form for example the
chlorine gas or other biological agents that can be spread by aerosol or other
hazardous air particles. In the chemical industry today when handling hazardous
materials as in to clean after leaking toxic canisters and cleaning after hazard spills.
Some gas masks are also respirators because the word gas mask is often used to be
described for military equipment also the user of the gas mask is not protected
from gases that the skin can absorb that either needs an NBC suit or a hazard suit.
The traditional gas mask style are with two small circular eye windows originated
from glass or acrylic as glass is brittle, glass eye windows had to be kept small and
thick, later the discovery of polycarbonate allowed gas masks to have a big full
face window. Some mask have one or two filter attached to the face piece other
have a large filter connected to face piece by a hose.
Absorption is the process of being drawn into a usually large body or substrate ,
and adsorption is the process of deposition upon a surface. This can be used to
remove both particulate and gaseous hazards. Although some form of reaction may
or will take place though it is not necessary maybe for a positive toxic particles use
a negative substrate. The substrate maybe activated carbon this is very effective
and also very simple like using a damp cloth to stop from breathing in smoke in a
fire.
Gas mask have a limited useful life span but that ultimately depends on the
capacity of the filter. Once the filter has been saturated with hazardous chemicals
the filter will cease protection and maybe be even cause the user some harm.
Filter classification
The filter is selected according to the toxic compound. Each filter type protects
against a particular hazard:










AX - Low-boiling (≤65 °C) organic compounds
A - High-boiling (>65 °C) organic compounds
B - Inorganic gases hydrogen sulfide, chlorine, H
E - Sulfur dioxide and hydrogen chloride (acidic gases)
K - Ammonia and Amines
CO - Carbon monoxide
Hg - Mercury
Reactor - Iodine and methyl iodide (radioactive)
P - Particles; classified as P1, P2, and P3 according to removal efficiency
ABEK, ABEK-P3, ABEK-HgP3 or other combination filters against
multiple hazards
Use of a gas mask
A modern mask typically is constructed of an elastic polymer in numerous
sizes and it is fitted with various adjustable which can be tightened which
are used to secure a good fit. It is crucial that it is connected that a filter
cartridge near the mouth directly or attached next to the face by a hose.
The first filter was a common sponge used by the ancient Greece and an
early model in Iraq during the 19th century then later developed to what it is
today
The common filter used was activated charcoal as charcoal is a natural
poison absorbent and an extremely high surface area which attract all
pollutants from the air. The pollutants does not react with the carbon but are
absorbed into the pores. Over time the filter becomes thoroughly coated and
cease to filter out pollutants however the filter can be reused by heating it
over a high heat which burns off the pollutant. The first effective filtering
activated charcoal gas mask in the world was invented in 1915 by a Russian
chemist.
In the first gas masks of world war 1 it was first using that wood charcoal
was a good poison absorbent but about in 1918 was found that it shells and
nuts charcoal was a better absorbent than wood charcoal.