A respirator is a personal protective device designed to safeguard the user from inhaling hazardous atmospheres, such as dusts, fumes, vapors, or gases. Unlike simple face coverings that may filter some particles, a respirator forms a seal against the face to ensure that all inhaled air passes through a filter or is supplied from a clean source. Because improper use or selection of this equipment can result in severe injury or death, its use is governed by strict regulatory standards, which in the US are overseen by the Occupational Safety and Health Administration (OSHA). These requirements establish a comprehensive program that must be completed before an individual uses a respirator in a hazardous environment.
Selecting the Correct Device for the Hazard
The first step before a respirator is ever donned is a thorough assessment of the workplace environment and its hazards. This process requires identifying the specific airborne contaminants present, their physical form, and their concentration levels. The measured concentration must then be compared against established Permissible Exposure Limits (PELs) to determine the necessary level of protection.
This hazard assessment dictates the type of respirator required, which must be selected based on its Assigned Protection Factor (APF). The APF is a numerical rating that indicates the expected level of protection, representing how many times the respirator can reduce the concentration of the contaminant the user breathes compared to the outside air. For example, a half-mask air-purifying respirator typically has an APF of 10, meaning it can be used in an atmosphere up to ten times the PEL.
Respirators are broadly categorized into air-purifying devices, which filter contaminants from ambient air, and atmosphere-supplying devices, which deliver clean air from an external source. Air-purifying models, like N95s or half-masks with cartridges, are unsuitable for environments that are immediately dangerous to life or health (IDLH) or oxygen-deficient. In those high-risk situations, a supplied-air respirator (SAR) or a self-contained breathing apparatus (SCBA) is required.
The Mandatory Medical Clearance Process
Once the appropriate device is selected, the individual must undergo a medical evaluation to ensure they are physically capable of wearing the respirator safely. Wearing a respirator, particularly a tight-fitting model, can place a physiological burden on the user’s heart and lungs. This evaluation must be completed before any fit testing or actual use of the device occurs.
The evaluation typically begins with a confidential medical questionnaire, often modeled after the one provided in OSHA’s Appendix C. This document details the employee’s health history, focusing on cardiovascular and respiratory issues like asthma or heart conditions, which could be worsened by the stress of respirator use. The employer must provide the medical professional with details about the respirator type, its weight, and the expected duration and frequency of use.
A licensed healthcare professional (LHP) reviews the questionnaire and determines if the individual is cleared to wear the equipment. Depending on the answers, the LHP may require a follow-up physical examination or additional tests, such as pulmonary function tests. The LHP then issues a written recommendation to the employer, detailing whether the employee is cleared for use, cleared with restrictions, or not cleared.
Comprehensive User Training Requirements
After medical clearance is obtained, the individual must receive comprehensive training specific to the device they will use. This instruction ensures the user fully understands the equipment and its limitations before entering a hazardous area. The training must be understandable to the worker and provided before the first use of the respirator.
Key elements of this instruction include why the respirator is necessary for the specific job and the conditions under which it will protect them. Users must be taught the proper procedures for putting the respirator on and taking it off, often called donning and doffing. The training also covers how to inspect the device for defects, how to clean and store it properly after use, and when to replace filters or cartridges.
Workers must be aware of the respirator’s limitations, such as the fact that an air-purifying respirator will not function in an oxygen-deficient atmosphere. Training must also cover emergency procedures and how to recognize medical signs or symptoms that could limit or prohibit continued respirator use. This comprehensive training must be repeated at least annually to reinforce knowledge and address any changes in the workplace.
Ensuring a Proper Seal Through Fit Testing
A final step for any tight-fitting respirator—such as N95s, half-masks, or full facepieces—is fit testing, which verifies the equipment seals correctly to the user’s face. Without a proper seal, airborne contaminants can bypass the filter or air supply, rendering the medical clearance and training ineffective. The fit test must be performed using the exact make, model, style, and size of the respirator the employee will use on the job.
There are two primary methods for testing the seal: Qualitative Fit Testing (QLFT) and Quantitative Fit Testing (QNFT). QLFT is a subjective, pass/fail test that relies on the user’s ability to detect a test agent, such as a bitter or sweet aerosol like saccharin, sprayed into a hood surrounding the head. This method is suitable for most half-mask respirators.
QNFT is an objective, machine-based test that measures the actual amount of leakage into the facepiece. This method uses specialized equipment, like a Portacount, to generate a numerical result called a “fit factor.” QNFT is required for certain higher-protection devices and is often preferred due to its accuracy and ability to generate specific data.
Fit testing must be repeated at least every twelve months and whenever a significant facial change occurs, such as major dental work or a substantial weight fluctuation. The employee must also perform a quick user seal check—either a positive or negative pressure check—every time they put the respirator on.