Topic : Personal Protective Gears
LIMITATIONS OF CARTRIDGE-TYPE RESPIRATORS
A half mask cartridge-type respirator is the most common type used for protection against organic vapors, dusts, mists, acid gases, and fumes. You should be aware, however, that respirators of this type provide adequate protection only under limited conditions. This type of respirator is designed mainly for short-term operations that do not contain atmospheres that are "immediately dangerous to life." To use this type of respirator you must know both the type and concentration of contaminants in the air.
Cartridge type respirators are approved only for low concentrations of contaminants in the air, the maximum permitted level of which depends on the "respiratory protection factor" (a measure of the degree of protection provided to the wearer). If a qualitative fit test is used (for example banana oil, or smoke tubes) a respiratory protection factor of 10 must be used. To determine the maximum concentration of airborne contaminants permitted in the air where the respirator will be used, the permissible time weighted average concentration (TWA or TLV) of the contaminant is multiplied by 10. For example, the TLV for lead fume is .15 mg/m 3, so the maximum concentration permitted in the air when using this type of respirator is 1.5 mg/m3. (TLVs are published by the American Conference of Governmental Industrial Hygienists (ACGIH).
Also, remember that a cartridge-type respirator does not generate breathing air and the oxygen content of the area must be at least 19.5% to use this type of respirator. In addition, it must also be worn only in the presence of moderately toxic air contaminants that have distinctive warning properties such as odor, irritation, or taste. The purpose of this requirement is to allow the user to tell when the cartridges have become exhausted. If you can detect the contaminant inside the mask, it means you must exit the area immediately and change the cartridge. Other things you should be aware of when wearing a cartridge-type respirator:
- Never enter a confined space with a cartridge-type respirator unless you know for sure that the space has been tested for oxygen content and toxic air contaminants, and that entry with this type of respirator is allowable and that entry has been approved.
- Never work in toxic vapors for which the respirator cartridge was not intended. There are many different types and combinations of cartridges--each for a specific type of hazard that is described on the band surrounding the cartridge. Also be sure the cartridges are the type the manufacturer specifies for your respirator. In general, they are not interchangeable from one manufacture to another. Ask your supervisor if you have doubts about these factors.
- Be sure your respirator fits your face properly. Most manufacturers provide at least three sizes of face pieces and one of them should fit you better than others. Your supervisor will help you select the proper size so that you get a good respirator fit.
- Respirators are available upon request from your supervisor.
- Dust respirators (i.e. paper/light filter masks) are recommended when working in blowing sand, concrete handling, grinding, carpenter shops when sawing wood, and near smoky sources, etc.
- Canister/ cartridge chemical respirators will be requested as advised in MSDS through the Project Safety Department. These respirators may be required when entering vessels, spray painting or when other toxics cannot be removed from the work area.A Safety Department representative should be contacted for advice if such circumstances occur.
- In emergencies or very special instances, air supplied respirators will be issued by the Safety Department, such as air packs, or air line respirators.
- Any employee who is assigned to wear an air supplied respirator must first receive suitable training and medical approval. Training will be conducted by the Safety Department; while medical approval t can be arranged through them and conducted at the nearest clinic.
- Air compressor should be fitted with approved air filtering and sampling system before been utilized as breathing air source.
- Medical approval is required only for air supplied respirators. Other respirators can be used by all employees as necessary.
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