The provision of personal protective equipment (PPE) is one of the last methods of control against health hazards that impact the cardiorespiratory system at the workplace. However, many employers resort to this type of control in the interim. Engineering controls or other types of controls higher on the control hierarchy require more time to evaluate and assess, before they can be implemented. (Learn more in "Introduction to Hazard Identification Studies".)
Despite this, deciding to provide employees with PPE to protect them from the risks at the workplace is not a straightforward decision as it involves a variety of factors. If it is an inhalation risk requiring provision of respirators, employers not only need to select the correct type but to also ensure that the respirators are fit-tested to the employees.
Respiratory Protection Dependent on Fit
A worker who is issued and is wearing a respirator may feel adequately protected from all potential hazards in the workplace and may therefore neglect the use of engineering controls, violate administrative control guidelines, and ignore required work practices. If the employer does not pay sufficient attention to the selection, fitting, training and maintenance of respirators for their workers, the worker’s exposure to airborne chemical hazards could be as high as for those of unprotected workers.
Respirators are often handed out without adequate attention to any of these precautions. It is common, for example, to see workers with beards wearing negative pressure air-purifying respirators (a disposable particulate respirator), in areas where contaminants are present in the air. The devices are useless unless they fit tightly, which is nearly impossible if the wearer has facial hair.
Fit is also dependent on worker training as to how to use the equipment. In addition, fatigue can influence whether or not the worker follows training. (Learn more in "Breaks During Work Are Necessary for Employee Well-Being and Work Performance".) Night shift workers are particularly vulnerable to risks associated with fatigue-based fit errors. (Learn more in "Fatigue Management in Night Shift Workers and Employer Risks".) A proper fit can also impact ergonomics and therefore morale.
What is a Respirator Fit Test?
It is important that the fit of the face piece of a respirator is tested prior to its use. According to OSHA, a fit test tests the seal between the respirator's face piece and the worker’s face. This test involves two people, the wearer of the PPE and the person administering the test. The comfort of the respirator face piece on the wearer should be checked. There are two types of respirator fit testing, qualitative or quantitative.
In a qualitative fit test (QLFT), an irritant smoke or odorous vapor is used. If the individual wearing the respirator detects the odor, this indicates that the respirator fit is inadequate. This test is fairly east to perform as it is quick, convenient and fairly reliable. However, the QLFT may fail to address respirator fit especially in cases where the person is insensitive to the chemical indicator being used. This method of fit testing is best used to fit test negative pressure air-purifying respirators that must achieve a fit factor of 100 or less.
On the other hand, a quantitative fit test (QNFT) is performed with instrumentation to detect the leakage of the nontoxic test atmosphere. This test, which does not rely on subjective human response, is recommended prior to working in immediately dangerous to life and health (IDLH) or other toxic atmospheres.
A fit factor is a quantitative estimate of the fit of a particular respirator to a specific individual and typically estimates the ration of the concentration of a particulate or substance in ambient air to its concentration inside the respirator when worn. Usually, a minimum fit factor of at least 100 is necessary for a half-mask respirator. For a full face piece negative pressure respirator, a minimum fit factor of at least 500 is required.
Is Fit Testing Legally Required?
In the US, respirator fit testing is required by OSHA for any employees required to wear respirators under OSHA rules. The American National Standards Institute (ANSI) and Occupational Safety and Health Administration (OSHA) provide guidance documents pertaining to fit test protocols including how to conduct fit testing and the appropriate methods for it. Fit testing is usually undertaken once or twice a year.
In addition to the required annual or biannual fit testing, it’s highly recommended to repeat a fit test for the following reasons:
- The employee is provided with a different type/ model of respirator other than the type/ model they were initially fit tested with
- If the employee experiences significant change to their physical conditions e.g. weight loss/ gain (especially if a worker becomes obese or loses significant weight), dental changes or cosmetic surgery
Repeated fit testing can also be an opportune time to check if the employee is putting on their respirator correctly as over time, they may have forgotten how to correctly don and use their respirator.
Who Can Perform Fit Testing?
Conducting a correct fit test requires knowledge, time, and attention to detail. As per OSHA’s guidelines, a person conducting the fit test needs to be familiar with the acceptable fit test methods under regulations as well as the limitations of the specific models of respirators being tested and used at that workplace. It is the responsibility of the employer that the persons who have been charged with administering the fit test are able to do the following:
- Prepare test solutions
- Calibrate equipment
- Perform tests properly
- Recognize invalid tests and
- Ensure that the test equipment is in proper working order
Fit tests conducted incorrectly can result in additional danger to the employee and increased exposure.
In conclusion, providing respirators for workers who are at risk of inhaling hazardous chemicals at work is not enough. Workers wearing respirators need to be fit tested to ensure that the respirators are protecting them as they're designed to do.