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DEFINATION
For the purpose of this standard apart from the definitions given in IS 8347, the following shall apply:
Chemical Filter
A container with either a filter, sorbent or catalyst, or combination of these items, which removes specific
Gaseous & Vapor contaminant(s) from the atmosphere, passed through the container.
Disposable Respirator
A device for which maintenance is not intended and which is designed to be discarded after excessive breathing
resistance, sorbet exhaustion, physical damage or end of service life renders it unsuitable for use.
End of Service Life Indicator
A system that warns the user of the approach of the end of adequate respiratory protection.
Full-face Mask
Face piece Covering mouth, nose, chin & Eyes.
Half face Mask
Face piece covering mouth, nose & chin
Hazardous atmosphere
An atmosphere that contains a contaminant in excess of its permissible exposure level or that is oxygen
deficient.
Immediately Dangerous Health to Life or (IDLH) level
Any atmosphere that poses an immediate hazard to life or poses immediate irreversible debilitating effects on
health or impairs the ability to escape.
Loose fitting face piece
A respiratory inlet covering that is designed to form a partial seal with the face, does not cover the neck &
shoulders and may or may not offer head protection against impact and penetration.
Negative Pressure Respirator
A respirator in which the air pressure inside the respiratory inlet covering is less than the ambient air pressure
during inhalation.
Poor Warning properties
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A substance whose odour, taste, or irritation effects are not detectable or not persistent at concentrations at or
below its permissible exposure level.
Positive Pressure Respirator
A respirator in which the pressure inside the respiratory inlet covering is higher than the ambient air pressure.
Protection factor:
Ratio of the concentration of contaminant present in the ambient atmosphere to its concentration in the air
inhaled by the wearer of a respiratory protective device.
Radionuclide
An atom that spontaneously emits atomic particles (Proton, electron, neutron) gamma or X-ray radiation.
Respirator
A personal protective device to protect the user from inhalation of hazardous atmosphere.
Respirator inlet covering
The portion of a respirator that connects the user’s respiratory tract to an Filter (air purifying device) or a
respirable gas source or both. It may be a face piece, helmet or hood. It serves as a barrier against the
contaminated atmosphere and as a framework to which air purifying or air supplying elements may be attached.
Service Life
The period of time that a respirator provides adequate protection to the user.
Tight fitting face piece
A respiratory inlet covering that is designed to form a complete seal with the face such as a half face mask and
full-face mask.
Time weighted average (TWA)
The concentration of a contaminant in air determined by adding together the products of each concentration and
the corresponding time over which that concentration was measured, and dividing the sum by the total time over
which the measurements were taken.
Contaminant- Undesirable, solid, liquid or gaseous substances in the air.
Fog-An atmosphere in which visibility is reduced because of cloud of some substances.
Smoke-general term denoting an aerosol generated by incomplete combustion.
Dust- General Term denoting solid particles.
Fumes-Fine solid aerosol which maybe chemically generated or of metallic origin. It is generally less than one
diameter.
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Respirable dust-Particle having 50% cut point of 4micron.These particles may be hazardous when deposited
in the gas exchange region.
Thoracic- Particles having a 50% cut point of 10micron.These particles may b hazardous when deposited in
the lung airway.
Inhalable-Particles having a 50% cut point of 100micron.These particle may be hazardous when deposited in
the head airway region.
Toxic dust- dust which may be harmful to the respiratory system or to the other parts of the body after passing
from the respiratory tract into the blood stream.
Aerosol- Suspension of solid, liquid or solid and liquid particles in gaseous medium, having a negligible
falling velocity (generally considered to be less than 0.25m|s)
Mist- General Term denoting a liquid aerosol.
Smog- A combination mixture of fog and smoke.
Vapor-Gaseous phase of a substance which is liquid or solid at 20oC and 1 bar (absolute)
LIMITS
TLV/OEL-Threshold limit value or occupational exposure limit. Air-borne concentration of toxic substances
and represents condition under which it is believed that nearly all workers may by repeatedly exposed day after
day without adverse effect.
IDLH- Immediately dangerous to life and health.
TLV-STEL- Short-term exposure limit. A 15-minutes TWA exposure that should not be exceeded at any time
during a work-day, even if the TWA is within the TLV.
If limit of gaseous and vapors contaminant gets exceeded then following
Asphyxiants: they interfere with utilization of O2 in the body.
Simple asphyxiants: These are physiologically inert substances that dilute O2 in the air, for ex-N, H, CH3
and CO2.
Chemical asphyxiates-In low concentration, these interfere with the supply or utilization of O2 in the body
by chemically reaching with blood, for example CO, HCN, cynogens and nit riles.
Irritants-These are corrosive in action. They may cause irritation and inflammation of parts of the respiratory
system (also skin and eyes) and ammonia, HCL, PHOSGENE and arsenic dichloride.
RESPIRATOR- A personal protective to protect the user from inhalation of hazardous atmosphere.
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Disposal respirator- A device for which maintenance is not intended and which is designed to be discarded
after excessive breathing resistance, sorbent exhaustion, physical damage or end service life renders it
unsuitable for use.
Full-face piece- A face piece that cover the face from roughly the hairline to below the chin.
Half face piece- A face piece that fits cover the nose and under the chin.
Loose fitting face piece- A respiratory inlet covering that is designed to form partial seal with the face, does
not cover the neck and shoulders and may or may not offer head protection against impact and penetration.
Negative pressure respirator - A respirator in which air pressure inside the respiratory inlet covering is less
than the ambient air pressure during inhalation.
Positive pressure respirator- A respirator in which the presence inside the respiratory inlet covering is
higher than the ambient air pressure.
Tight fitting face piece- A respiratory inlet covering that is designed to form a complete seal with the face
such as a half face mask and full face mask.
Respirator inlet covering- The portion of respirator that connects the user’s respiratory tract to an air
purifying device or a respirable gas source or both. It may be a face piece, helmet or hood. It serves as a barrier
against the contaminant atmosphere and as a framework to which air purifying or air supplying elements may
be attached.
Required minimum protection factor- The protection factor required to reduce exposure to an accepted
level. It is expressed as ratio of ambient air concentration of a contaminant to its permissible exposure level.
Service life – The period of that a respirator provides adequate protection to the user.
End of service life indicator- A system that warns the user of the approach of the end of adequate respirator
protection.
