Respirators in the Workplace
Respirators in the workplace play an important role in the protection of workers and it is essential that both workers and employers understand how to use them properly. Workers should use respirators for protection from contaminants in the air only if other hazard control methods are not practical or possible under the circumstances. Respiratory hazards can include airborne contaminants such as biological contaminants, dusts, mists, fumes, and gases, or oxygen-deficient atmospheres and more than one respiratory hazard can be present at the same time.
Some types of atmospheres contain concentrations of hazardous substances that places the worker in immediate danger (IDLH) as these concentrations would impair the ability to leave the work area (self-rescue) or potentially cause irreversible health effects.
Respiratory Protection Programs
A written respiratory program consists of all steps necessary to protect workers from exposure to a substance or system, the training and the procedures required to monitor worker exposure and their health to hazards such as chemicals, materials and substances. The program will also describe proper procedures for selecting and operating respiratory protective equipment. The correct use of a respirator is just as important as selecting the proper respirator. Without a complete respiratory protection program, workers will not receive the best protection from a respirator even if it is the correct choice for a specific job. A respiratory protection program includes several components such as:
- Hazard identification and control
- Exposure assessment
- Respirator selection
- Respirator fit-testing
- Training program
- Inspection and record keeping
- Cleaning and sanitizing respirators
- Repairing and maintaining respirators
- Proper storage of respirators
- Health surveillance
- Standard operating procedures (available in written form)
- Program evaluation.
The two main types are air-purifying respirators (APRs) and supplied-air respirators (SARs).
Air-Purifying Respirators can remove contaminants in the air that you breathe by filtering out particulates. Other APRs purify air by adsorbing gases or vapours on a sorbent (adsorbing material) in a cartridge or canister. They are tight-fitting and are available in several forms including mouth fit respirator, quarter-mask, half-face mask and full face piece.
Examples of air-purifying respirators (APRs) include:
- Particulate respirators
- Chemical cartridge respirators
- Gas masks
- Powered air-purifying respirators (PAPRs)
Supplied-Air Respirators (SARs) supply clean air from a compressed air tank or through an airline. This air is not from the work room area. The air supplied in tanks or from compressors must meet certain standards for purity and moisture content. Supplied-air respirators may have either tight-fitting or loose-fitting respiratory inlets. Respirators with tight-fitting respiratory inlets have half or full facepieces. Types with loose-fitting respiratory inlets can be hoods or helmets that cover the head and neck, or loose-fitting facepieces with rubber or fabric side shields.
These are supplied with air through airlines.
Examples of supplied-air respirators (SARs) include:
- Self-contained breathing apparatus (SCBA)
- Airline supplied-air respirators
- Protective suits encapsulating the wearer’s body and incorporate a life-support system
There are different classes of particulate filters, depending on the particulate material. They are also classified based on levels of oil resistance and filter efficiency. Oil can break down cert in types of filters which means it is important to know the materials you are working with at all times and always select the right cartridge for your respirator. The main categories are:
- N series (Not resistant to oil)
- R series (Resistant to oil)
- P series (Oil-Proof)
Selecting the Right Respirator
Choosing a respirator in the workplace is a complicated matter. Experienced safety professionals or occupational hygienists familiar with the actual workplace environment should select the proper respirator after evaluating all relevant factors. This includes considering the limitations of each class of respirator and the situations specific to the workplace. Prior to selecting the proper respirator, ensure you have:
- Identified the respiratory hazard
- Evaluated the hazard
- Considered whether engineering controls are feasible
A fit test is the best way to determine if a tight-fitting respirator fits properly and is protecting workers from hazardous, airborne agents. It is performed on the person who is going to wear a respirator. Achieving a good fit is necessary for the respirator to work properly. A mask that forms a tight seal against the face of the wearer is a proper fit.
If an employer requires a worker to wear the following types of respirators, a fit test is needed on any of the following masks:
- Filtering face pieces such as N95 or KN95 masks
- Half-face respirators
- Full-face respirators
Fit Test Requirements
If a worker has never had a fit test before and if they are required to wear a respirator, they need one in accordance with the Canadian Standards Association (CSA) and Ontario’s
Occupational Safety Act (OHSA). As well, workers need a fit test:
- At least every two years
- Whenever changes to the user’s physical condition could affect the respirator fit such as due to weight gain or loss, surgery, or major dental work
- If they are using a new respirator make or model
Types of Fit Tests
Positive and Negative Pressure User Seal Checks
Negative-pressure and positive-pressure user seal checks are conducted on tight-fitting electrometric face pieces to check the respirator seal in the field. They are simple and quick, and can be performed by the wearer to check the respirator fit at any time during a work shift.
- The positive-pressure test is conducted by covering the exhalation valve, usually located on the bottom of the respirator, with the palm of the hand and exhaling gently. The face piece should puff slightly away from the face without allowing air to escape.
- The negative-pressure test involves covering the air inlets and then inhaling. A slight collapse of the face piece with no air leakage indicates a satisfactory fit.
Qualitative and Quantitative Fit Testing
Qualitative Fit Testing (QLFT) and Quantitative Fit Testing (QNFT) test the effectiveness of a mask’s fit. A qualitative fit test is based on the wearer’s ability to taste a harmless solution at very low levels. A quantitative fit test uses a specialized machine to measure the particles inside and outside the mask.
A QLFT uses a solution to test if a respirator fits. This involves the worker putting their respirator on, donning a hood and spraying a sweet or bitter solution to determine if the worker can detect the solution. This includes going through a variety of exercises. If the person being tested can taste the solution then the respirator is not a good fit. If they cannot test the solution, the mask is a good fit.
A QNFT is conducted by an operator using an approved quantitative fit testing machine such as the PortaCount Respirator Fit Tester. Just like in qualitative fit tests, the person being tested will be asked to go through different exercises such as talking, turning their head from side to side and nodding to help make sure the mask will continue to fit over the course of an employee’s workday. Throughout the test, the machine takes measurements of the level of particles inside the mask compared to the ambient air outside of the mask. If there is high particle count inside the mask, then a good seal has not been achieved. If there is a very low particle count, the mask is a good fit.
Respirators must be maintained in good operating condition if they are to be effective. The maintenance program should follow the manufacturer’s instructions.
Cleaning and Disinfection
Respirators must be cleaned and disinfected after use on each shift, or more often if necessary, if they are used exclusively by one worker.
Inspection and Repair
After being cleaned and disinfected, each respirator must be inspected to determine if it is in proper working condition. Where the inspection indicates that parts are damaged or deteriorated, they must be replaced before the respirator is used again.
Respirators must be stored in a clean, convenient and sanitary location. The storage area should protect the equipment from dust, sunlight, heat, extreme cold, excessive moisture and damaging chemicals. It is recommended that individual respirators be placed in plastic bags or closed containers and stored in a manner that will prevent distortion of rubber or plastic parts.