What Does Qualitative Fit Test (QLFT) Mean?
A qualitative fit test (QLFT) is a testing method used to assess the effectiveness of a respirator when worn by a specific employee. This testing, known as mask fit testing, is conducted when a worker selects a tight-fitting respirator for use in the workplace. A QLFT should simulate the conditions under which the mask will be worn by the employee. Thus, it is conducted with the worker wearing the chosen mask and any other equipment he or she will wear during the work day.
During a qualitative fit test, a worker wearing the selected respirator is exposed ambient air containing a non-toxic airborne contaminants. U.S. Occupational Safety and Health regulations allow testers to use one of four substances for qualitative testing. Each of the substances is designed to trigger a sensory reaction if it enters the wearer's airways through a leak in the face to mask seal of the respirator. Isoamyl acetate has a fruity aroma that a worker will be able to smell. Saccharin solution carries a sweet taste that can be detected when inhaled. Bitrix has highly noticeable a bitter taste. A fourth alternative, stannic chloride, is an irritating smoke with a strong odor.
WorkplaceTesting Explains Qualitative Fit Test (QLFT)
Under U.S. Occupational Safety and Health (OSHA) guidelines, an employee must select a respirator that fits him or her properly and effectively protects that individual for exposure to workplace hazards before working in a workplace where exposure to airborne contaminants. The process of selecting the individual's respirator includes mask fit testing. Once selected a mask may be evaluated using either qualitative or quantitative analysis.
After a tight-fitting respirator has been approved for a specific worker, additional testing should be conducted annually to confirm its effectiveness. Testing may also be required if the individual's physical features change or additional physical or protective equipment, such as protective eye wear or hearing aids, is used in conjunction with the respirator.
OSHA regulations limit the use of qualitative fit tests to those respirators that need to qualify with an assigned protection factor (APF) of 10 or lower. A facepiece with a higher APF may be evaluated using a qualitative fit test, but only if it will not be used for situations requiring a factor above 10. When a higher protection factor is needed for work in a particular environment, a quantitative fit test (QNFT) must be used to assess the selected respirator.