Two main classes of respirators are available:
Air-Purifying Respirators (APR)
These respirators are designed to filter air borne contaminants such as fumes or noxious dust. Other forms of APR models use a canister or cartridge containing a material that absorbs the contaminants.
APRs are tight fitting to the face and have different designs. These designs include particulate respirators, powered air-purifying respirator (PAPR), gas masks and chemical cartridge respirators. They come in four different designs, including:
Full face piece – Fully covers the face from underneath the chin to an area above the eyes. This feature provides added protection to the eyes, especially from chemical irritants.
Half-face mask – Gives protection from beneath the chin to and including the nostrils.
Quarter-mask – Protects the mouth and nose.
Mouth bit respirator – Normally used for escaping a hazardous situation only. Contains a bit which is inserted into the mouth and nose clip to seal the nostrils closed.
Supplied-air respirator (SAR)
These respirators provide breathable air via an air line or a compressed work tank. SARs come in two different types. The first has a loose fitting respiratory inlet, such as a helmet or a hood which envelopes both the neck and head, that is supplied purified air through airlines. This type may have face pieces which fit loosely.
The other form of SAR has either a half or full face piece and has very snug respiratory inlets.
Choosing the Most Suitable Respirator
Selecting the most suitable respirator must be performed by an expert, such as a safety professional. The expert will consider the appropriate apparatus only after they have identified and evaluated the potential respiratory hazard and considered the relative limitations of the respiratory apparatus for the situation.
Key Questions to Ask
Here are some factors an employer should consider when determining whether a respirator may be required:
Establish the existence of a hazard by considering warnings about the material, like its chemical components or the nature of the particulates that might be released through the work performed.
Determine whether there is limited oxygen present.
Is the hazard airborne such as a particulate, fume, or vapor?
Ask whether the respirator will be used for an emergency or in combating fires.
Evaluate whether the work is strenuous and will be performed in hazardous atmospheric circumstances.
Is there any agent present which might be possibly fatal, carcinogenic, skin absorbable or acts as an irritant?
Will the work be conducted in a confined space or will the worker be exposed to abnormal temperatures?
The key is that respirators should be used to suit the work. The proper choice of respirator is vital to the health and safety of workers in many types of employment.