Respirator Fit Test Overview & Guide

IH Program Management

Respirators are the last line of defense between workers and harmful air contaminants, irritants and other workplace respiratory hazards, but simply putting on a respirator doesn’t mean you’re protected. Whether it’s an N95 filtering facepiece respirator that we’re all so familiar with now or a full self-contained breathing apparatus (SCBA), if respirators don’t fit properly, they provide little or no protection for workers.

That’s why regulations like OSHA’s Respiratory Protection Standard and other occupational health and safety (OHS) regulations require employers to perform and document fit tests for every worker who wears a respirator, and for every covered respirator type used in your workplace, to make sure workers are protected to the highest possible degree.

Here, we’ll take a closer look at some of the most common questions regarding respirator fit testing to help you break down the process and eliminate any confusion you might have around this absolutely critical component of workplace respiratory protection.

What is a respirator fit test?

A respirator fit test is an evaluation procedure used to verify that respiratory protective equipment (respirators) used by workers is properly sized for the individual user, that it functions according to the manufacturer’s specifications, and that a respirator actually provides the level of protection it is designed to provide.

Appendix A of the Respiratory Protection Standard contains OSHA’s approved fit test protocols, which are the testing methods and evaluation criteria employers are permitted to use when performing fit tests. There are a variety of approved protocols that may be used depending on the type of respirators used in your workplace and the respiratory hazards present, so employers should take some time to familiarize themselves with the details of these fit test protocols to determine which testing protocol is appropriate for the respirators in your workplace.

How do I perform a respirator fit test?

OSHA’s Respiratory Protection Standard specifies two primary types of respirator fit tests—qualitative and quantitative. The qualitative and quantitative testing protocols that may be used in workplaces to verify respirator fit are described below.  

Qualitative Fit Test (QLFT)

A qualitative fit test (QLFT) protocol is used to fit-test the following respirator types:

  • Negative-pressure, air-purifying respirators used in atmospheres where the hazard is at less than 10 times the permissible exposure limit (PEL).
  • Tight fitting facepieces used with powered and atmosphere-supplying respirators.

QLFT is pass/fail test that relies on the user’s senses to detect the presence of one of four OSHA-accepted test agents that may be used in the testing process:

  • Isoamyl acetate (banana smell); only for testing respirators with organic vapor cartridges.
  • Saccharin (sweet taste); can test respirators with a particulate filter of any class.
  • Bitrex® (bitter taste); can also test respirators with particulate filters of any class.
  • Irritant smoke (involuntary cough reflex); only for testing respirators with level 100 particulate filters.

During a QLFT, a respirator user is exposed to a prescribed amount of the appropriate test agent under prescribed testing conditions. The user then performs the following seven exercises for 1 minute each to simulate basic motions and activities of work:

  • Normal breathing
  • Deep breathing
  • Moving head side to side
  • Moving head up and down
  • Bending over (or jogging in place if fit test unit doesn’t permit bending at the waist)
  • Talking
  • Normal breathing again

If the user is able to smell, taste or otherwise detect the testing agent in any amount, then the test is failed and the user must be retested. This includes repeating any odor sensitivity checks and fit test procedures. For the complete OSHA-approved QLFT protocols, click here.

Quantitative Fit Test (QNFT)

By contrast, a quantitative fit test (QNFT) is an assessment of respirator fit based on numerical measurement of leakage into the respirator, rather than a user’s ability to detect a test agent. A scientific instrument is used to measure leakage around the face seal and the resulting measurement is used to calculate a numerical “fit factor.” QNFT can be used to fit-test any tight-fitting respirator, but must be performed according to one of three OSHA-accepted QNFT test protocols, including:

  • Generated Aerosol - uses a device to generate non-hazardous aerosol at a prescribed concentration (using corn oil, polyethylene glycol 400 [PEG 400], di-2-ethyl hexyl sebacate [DEHS] or sodium chloride) within a test chamber, while a specialized sampling probe is mounted within the respirator to analyze aerosol concentration.
  • Ambient aerosol condensation nuclei counter (CNC) – A condensation nuclei counter (CNC) such as the PortaCount® fit tester generates ambient aerosol of a test agent without the need for a test chamber, and a built in test probe measures and automatically calculates fit factor.
  • Controlled negative pressure (CNP)– The CNP fit test protocol avoids the use of ambient aerosol by exhausting air from a temporarily sealed respirator facepiece to generate and then maintain a constant negative pressure inside the facepiece. The level of pressure is selected to replicate the average negative pressure that causes leakage into the respirator under normal use conditions. With pressure held constant, air flow out of the respirator is equal to air flow into the respirator. Therefore, measurement of the exhaust stream that is required to hold the pressure in the temporarily sealed respirator constant yields a direct measure of leakage air flow into the respirator. Like the CNC protocol, CNP protocols are performed with a specialized testing device such as the OHD QuantiFit2 which simultaneously administers the test agent, analyzes the exhaust flow and calculates fit factor.

In addition to the testing equipment used, the QNFT protocols also differ in terms of the exercises a respirator user is required to perform during the test. While the motions in these exercises are essentially the same as those used in QLFT protocols, the duration of these exercises may vary depending on the QNFT protocol being used. Refer to the QNFT Protocols in Appendix A of the Respiratory Protection Standard for precise test exercise instructions.

The fit factor requirements are consistent across all QNFT protocols, with a fit factor of at least 100 required to satisfy testing requirements for half-mask respirators and a minimum fit factor of 500 for full facepiece negative-pressure respirators.

User Seal Checks: An Essential Everyday Test

In addition to QLFT and QNFT tests, employees who use tight-fitting respiratory protection should perform a user seal check each time they put on their respirator. In fact, user seal checks are required under the Respiratory Protection Standard, unless use of that respirator is voluntary. A user seal check ensures that the respirator is being worn right each time.

Appendix B-1 of the Respiratory Protection Standard specifies two methods employees can use to perform a user seal check: positive-pressure or negative-pressure seal checks.

Positive-pressure check - Close off the exhalation valve and exhale gently into the facepiece. The face fit is considered satisfactory if a slight positive pressure can be built up inside the facepiece without any evidence of outward leakage of air at the seal. For most respirators this method of leak testing requires the wearer to first remove the exhalation valve cover before closing off the exhalation valve and then carefully replacing it after the test.

Negative-pressure check - Close off the inlet opening of the canister or cartridge(s) by covering with the palm of the hand(s) or by replacing the filter seal(s), inhale gently so that the facepiece collapses slightly, and hold the breath for ten seconds. The design of the inlet opening of some cartridges cannot be effectively covered with the palm of the hand. The test can be performed by covering the inlet opening of the cartridge with a thin latex or nitrile glove. If the facepiece remains in its slightly collapsed condition and no inward leakage of air is detected, the tightness of the respirator is considered satisfactory.

If either a positive or negative-pressure seal check reveals leakage or faulty seal, workers should first adjust the fit of their respirator and re-test. If a leak persists, inspect the respirator facepiece for damage or excessive wear, ensure proper function of filter cartridges and exhaust vents, and replace the respirator if necessary.

What type of respirators require fit testing?

A fit test is required for all negative or positive pressure tight-fitting facepiece respirators. This includes both supplied-air respirators and air-purifying respirators, filtering facepiece (N95) respirators, half mask, full facepiece and powered-air purifying respirators. Guidance on which types of respirators require fit testing can be found in OSHA’s Small Entity Compliance Guide for the Respiratory Protection Standard. If any of these types of respirators are used in your workplace, you must meet the requirements under this part of the Standard.

How often to get a respirator fit test?

For workplaces covered under OSHA’s Respiratory Protection Standard, QLFT or QNFT fit testing is required before a user wears a mandatory respirator on the job and re-tested at least annually. A separate test is required for each respirator type used by a worker. In addition, fit tests should be performed:

  • Whenever a different size, style, model or make of respirator is used.
  • When any facial changes occur that could affect fit, such as significant weight fluctuation or dental work.

Before an employee can be required to use any respirator with a negative or positive pressure tight-fitting facepiece, the employee must be fit tested for that respirator. After the initial fit testing, subsequent fit tests must be performed at least annually, and whenever an employee switches to a different type of tight-fitting facepiece respirator.

Who can perform respirator fit testing?

OSHA doesn’t require any sort of certification for fit test administrators, only that they know how to conduct a test, recognize invalid/failed tests, and properly clean/calibrate/maintain equipment. Respirator fit test administrators should be highly familiar with the respirator types/models used in the workplace, their function and adjustment, use of fit test agents and testing equipment, fit test protocols, any applicable respiratory protection requirements (e.g. OSHA Respiratory Protection Standard) and other workplace standards with respiratory PPE requirements (e.g. Respirable Crystalline Silica, etc.)

Where can I get a respirator fit test done?

QLFT protocols are relatively easy to perform in-house, as the protocols are explicitly published in Appendix A of OSHA’s Respiratory Protection Standard, and testing kits that include everything you need can be purchased for a relatively low cost.

QNFT protocols are a little more technically complex in nature, and the testing equipment is considerably more expensive than QLFT test kits, but if your workplace has a large number of workers who regularly use respirators, performing QNFT in-house is a good option.

There are also many third-party respirator fit test service providers in the marketplace who can come to your workplace to perform and document fit testing, and/or rent out testing equipment if you choose to test in-house.

How do I ensure compliance with respirator fit test requirements?

One of the most difficult parts of compliance with OSHA fit testing requirements is scheduling and sufficiently documenting fit test results for all fit tests performed on all employees who require them, for every covered respirator type used in your workplace. The more employees who use respirators, the greater this challenge becomes.

Employers should consider implementing a software system that coordinates the scheduling, documentation and follow up of your required fit testing protocols and activities. This is particularly true for employers who need to manage fit testing compliance across multiple locations, or for large numbers of employees who use respirators in the workplace. If you can quickly and easily determine which employees use which types of respirators, what fit testing protocols are required for those respirator types, when fit tests must be performed and then document fit test results, you’ll be well on your way to ensuring compliance with fit testing requirements.

VelocityEHS Can Help!

The VelocityEHS Industrial Hygiene Solution includes our Respirator Fit Test (RFT) software, which standardizes the scheduling, documentation and follow up of your RFT activities, giving you a powerful platform for managing RFT requirements across multiple locations and large numbers of employees. You can easily determine which employees use which types of respirators, schedule and assign fit tests, and record results to easily demonstrate compliance. Built-in OSHA-approved testing protocols and a complete library of pre-test procedures make it easy to select and perform the right RFT protocols for the respirator types used in your workplace.

Simple and intuitive respirator fit testing is just one of the many expert-designed features you get with our Industrial Hygiene Solution. Request a demo today to learn how we can help you!