Respirator fit test

A respirator fit test checks whether a respirator properly fits the face of someone who wears it. The fitting characteristic of a respirator is the ability of the mask to separate a worker's respiratory system from ambient air.

This is achieved by tightly pressing the mask flush against the face (without gaps) to ensure an efficient seal on the mask perimeter. Because wearers cannot be protected if there are gaps, it is necessary to test the fit before entering into contaminated air. Multiple forms of the test exist.

Scientific studies have shown that if the mask size and shape is correctly fitted to the employees’ face, they will be better protected in hazardous workplaces.

The effectiveness of various types of respirators was measured in laboratories and in the workplace. These measurements showed that in practice, the effectiveness of negative pressure tight fitting respiratory protective devices (RPD) depends on leakage between mask and face, rather than the filters/canisters. This decrease in efficiency due to leakage manifested on a large scale during World War I, when gas masks were used to protect against chemical weapons. Poor fit or poorly situated masks could be fatal. The Russian army began to use short-term exposure to chlorine at low concentrations to solve this problem in 1917. Such testing helped convince the soldiers that their gas masks were reliable - because respirators were a novelty. Later, industrial workers were trained in gas chambers in the USSR (in preparation for the Second World War), and late'. German firefighters used a similar test between the First and Second World Wars. Diluted chloropicrin was used to test industrial gas masks. The Soviet Army used chloropicrin in tents with a floor space of 16 square meters.

The US army provides military training using an irritating smoke.

Respirator selection and use are regulated by national legislation in many countries. These requirements include a test of negative pressure mask for each individual wearer.

Qualitative and quantitative fit test methods (QLFT & QNFT) exist. Detailed descriptions are given in the US standard, developed by Occupational Safety and Health Administration OSHA. This standard regulates respirator selection and organization (Appendix A describes fit testing). Compliance with this standard is mandatory for US employers.

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