We’re nearly a year into the COVID-19 pandemic and masks have become a necessary part of life for billions of people worldwide. While the average person may be new to wearing a face covering, the concept of respiratory protection is nothing new to millions of workers across many industries.
From construction to agriculture to mining to general industry, workers rely on respiratory protection to work safely and protect their health. OSHA requires respirators, part of the PPE family, for employees working in hazardous conditions with airborne particles and fumes.
Because of the plethora of respirator options available, it’s essential to understand the ins and outs of the different forms of respirators. In this guide, we’ll walk you through respirators from fit to filter.
Grab Safesite’s Guide to Respirators chart as a PDF.
The Alphabet Soup of Respiratory Protection
Learning about respirators starts with a crash course in PPE vocabulary.
All respirators fall into the Respiratory Protective Equipment (RPE) category, which is a part of PPE. You may also hear respirators described as Respiratory Protective Devices.
As you familiarize yourself with PPE and RPE, you’ll run into many other acronyms. We’ll touch on most of these in this article, so keep this list handy for future reference.
- APR (Air-Purifying Respirator)
- APF (Assigned Protection Factor)
- BA (Breathing Apparatus)
- FFR (Filtering Facepiece Respirator)
- FF (Fit Factor)
- HEPA (High-Efficiency Particulate Air)
- NPF (Nominal Protection Factor)
- PAPR (Powered Air Purifying Respirator)
- RPD (Respiratory Protective Device)
- RPE (Respiratory Protective Equipment)
- PPE (Personal Protective Equipment)
- SCBA (Self Contained Breathing Apparatus)
- WPF (Workplace Protection Factor)
Masks vs. Respirators
As you educate your workers about PPE and RPE, it’s crucial to articulate the difference between a mask and a respirator.
Even though a mask covers the nose and mouth just like a respirator, masks do not offer the same safety protection as respirators. You cannot use them as a substitute.
Specific standards outlined below govern respirators and respiratory protection. Masks and face coverings do not adhere to any industry standards. You should always be sure you provide adequate protection that matches the hazard and the regulators surrounding the hazard.
What Are Protection Factors (APF, NPF, WPF)?
Every respirator comes with an Assigned Protection Factor, a number that tells the wearer how much protection that respirator offers. APFs generally range from 10 to 10,000. To earn an APF, a respirator goes through simulated workplace testing. A respirator with an APF of 10 means that it protects the wearer against ten times the normal permissible exposure limit of a particular hazardous substance.
Companies following OSHA standards must choose a respirator with an APF rating.
Another type of protection factor is Nominal Protection Factor, which isn’t a wholly reliable factor for the level of protection. Manufacturers determine an NPF via testing done in a lab setting. Lab testing provides a strong indication of protection, but it doesn’t give a true estimate of effectiveness in the field. Most companies only use NPF as a reference and rely on the APF to determine what type of respirator to purchase.
Manufacturers calculated the Workplace Protection Factor by taking the number of contaminants the worker would have inhaled without a respirator divided by the contaminant concentration inside the respirator facepiece. WPF is the most accurate value for protection levels.
Introduction to the Two Categories of RPE
RPE includes two categories: respirators, which purify the external air you breathe, and breathing apparatuses (BA), which supplies clean air for you to breathe.
Need a handy guide? Download our chart (PDF) featuring the different types of respirators.
Air-Purifying Respirators
Air-purifying respirators (APRs) remove hazardous gases, vapors, and aerosols out of the air before you breathe them in. APRs use filters, cartridges, or canisters to clarify the air before the user breathes it in.
Depending on the job hazard analysis, you will choose between several different types of APRs, including Filtering Facepiece Respirators (FFR), Elastomeric Facepiece Respirators, and Powered Air-Purifying Respirators (PAPR).
The Filtering Facepiece Respirator (FFR) is an unpowered respirator that covers the nose and mouth and must be fit tested. FFRs are disposable and should regularly be inspected for damage and usability. These respirators are only effective at filtering out particles such as dust, mist, and fumes. They provide no level of protection against gas or vapors.
Examples of FFRs include the N, R, and P series and 95, 99, and 100 efficiency levels. The N series are not resistant to oil, the R series are somewhat resistant to oil, and the P series are strongly resistant to oil.
The Elastometric Facepiece Respirator (EFR) comes in two variations, half-face and full-face. Both types should be fit tested before use, which we’ll touch on later. These respirators are reusable and come with replaceable cartridges and filters. They can be cleaned, disinfected, stored, and reused multiple times. Depending on the type of cartridge or filter used, they do protect against gas and vapors. The full-face version also has replaceable canisters and offers eye protection in addition to defense against gas, vapors, and particles.
The half-face has an Assigned Protection Factor of 10, and the full-face has an APF of 50.
Providing better breathing capabilities, Powered Air-Purifying Respirators (PAPRs) have an APF of 25 and offer protection against gases, vapors, and particles. PAPRs provide eye protection and have low breathing resistance. Manufacturers create PAPRs with reusable components and replaceable filters and cartridges. These battery-powered apparatus use a blower to pull air through the attached filters or cartridges.
If your employees use loose-fitting PAPRs, you do not have to perform fit testing even with facial hair. The tight-fitting PAPRs do need to be fit tested.
Atmosphere-Supplying Respirators
The second type of RPE is an atmosphere-supplying respirator, which provides clean air from an independent source. Atmosphere-supply respirators protect against vapors, gases, and particles. They also offer safety in oxygen-deficient areas.
The three types of atmosphere-supplying respirators are:
- supplied-air respirators (SARs)
- self-contained breathing apparatuses (SCBAs)
- combination SARs
Any atmosphere-supplying respirator you use must have approval from the National Institute for Occupational Safety and Health and follow OSHA standard 29 CFR 1910.134.
Supplied-air respirators (SARs) connect to a free-standing cylinder of breathable air by an airline hose. They can also be attached to an air compressor or another system supplying breathing air. Because they are lightweight, workers can use them for long periods. However, anyone wearing one has mobility because of the hose.
SARs come with hoods, helmets, or tight-fitting facepieces and have varying APRs. These devices deliver air in one of three ways:
- Continuous-flow: airflow is maintained constantly
- Demand: provide air depending on the user’s breathing and cause negative pressure during inhalation
- Pressure-demand: provide air depending on the user’s breathing and maintains positive pressure in the facepiece during use.
Self-contained breathing apparatuses (SCBAs) have an APF of 10,000. Because they have their own portable air supply, the wearer also has greater mobility. While they have a high APF and high mobility, SCBAs have a short service life and aren’t suitable for use over long periods.
The two types of SCBAs are:
- Open-circuit SCBAs have a full facepiece and contain the air supply in a pressurized cylinder on the wearer’s back. The circuit releases exhaled air back into the atmosphere and generally the service life is only 75 minutes. Firefighters often use open-circuit SCBAs when battling fires.
- Closed-circuit SCBAs recycle the breathed air by removing carbon dioxide and replacing it with oxygen. They have a duration of one to four hours, depending on the oxygen tank’s size and the user’s oxygen consumption.
The final type of atmosphere-supplying respirator is the combination SAR. Providing an APF of 1,000, these apparatus have a backup air supply used if the primary air supply fails. Typically, you’ll only use a combination SAR/SCBA for emergency rescue and escape situations because they have a short service life.
What Respiratory Hazards Occur in the Workplace?
Companies require employees to wear RPE when the company cannot remove the hazard in another way through confining the contaminant-producing operation, removing the contaminant through exhaust systems, or using less toxic materials. Airborne hazardous and toxic substances that respirators protect against generally fall into one of seven categories:
- Dusts in an industrial setting can be extremely dangerous. These dusts are the byproduct of larger solid organic or inorganic materials being reduced in size through crushing, grinding, drilling, or blasting.
- Fumes: When a volatilized solid condenses in cool air, particles called fumes form. Typically this process also includes a chemical reaction. Fumes also form in other ways, such as when magnesium metal is burned or during the welding process.
- Mists form when a finely divided liquid is suspended in air and can be dangerous when inhaled. Examples of hazardous mists include the oil mist created during cutting and grinding operations, acid mists from electroplating, and paint spray mist.
- Gases: Formless but dangerous, gases can change to a liquid or solid state through increased pressure and decreased temperature. Welding emits several gases, including acetylene, nitrogen, helium, and argon. Other examples of hazardous gases are carbon monoxide from internal combustion engines and hydrogen sulfide occurring whenever there is a decomposition of materials with sulfur in them.
- Vapors: Like gases, vapors are the gaseous forms of substances that are typically solid or liquid. Vapors are common in areas where cleaning and painting take place.
- Smoke: We’re taught from a young age that smoke is dangerous to breathe, and the same holds true in an industrial setting. Smoke can contain both droplets and dry particles, making it doubly dangerous.
- Oxygen deficiency: While breathing too much of the other hazards puts workers in danger, oxygen deficiency is an equally common hazard. A lack of oxygen can have detrimental effects on the human body and typically happens in confined spaces like storage tanks, vessels, towers, drums, tank cars, bins, sewers, septic tanks, utility tunnels, and pits.
A Short Guide Choosing the Right Respirator
Picking the best respirator for your company’s and employees’ needs can be a literal life or death choice; choosing the wrong respirator could mean injury or death for your workers. Fortunately, by following several steps, you can easily choose the right respirator to protect your employees.
Step 1: Identify Hazards
Figure out precisely what hazards your workers face in their work environments. You’ll accomplish by:
- Collecting information about the environment from the workers themselves through observations and JHAs
- Evaluating equipment and machinery operating manuals
- Reading Safety Data Sheets from chemical manufacturer
- Analyzing inspection reports and injury reports
You can also conduct an exposure assessment to determine what types of hazards—particles, gas, vapors, or a combination—are present.
So, what does this look like in real life? Imagine that ABC Company wants to outfit its welders with the proper RPE. The safety manager starts by going into the work environment to record the hazards. The manager then consults the operating manual for the particular welding equipment they use to determine what hazards pose a threat to workers’ safety. They find that their welding processes give off aluminum, aldehydes, and hydrogen fluoride.
Step 2: Determine the Level of Contaminants
Once you determine the types of hazards present, figure out the level of contaminants present.
Contaminants are usually measured in parts per million or milligrams per cubic meter and average over eight hours.
After finding the contaminants’ level, compare those to the occupational exposure limit (OEL) or permissible exposure limit (PEL) set by OSHA.
At ABC Company, the safety manager takes the results from the hazard audit and compares them to the OSHA limits. He finds that the OSHA PEL for aluminum is 5 mg/m and his workers face exposure to 50 mg/m.
Step 3: Figure Out the Protection Level Needed
OSHA requires that all respirators used in the workplace be NIOSH-approved and have an APF. You’ll use the hazard ratio to figure out what level of APF a respirator should have to protect in your workplace. Find the hazard ratio by dividing your exposure levels by the exposure limit.
So ABC Company’s hazard ratio would be 50 (the exposure level) divided by 5 (the exposure limit). The respirators that the company chooses should have an APF of at least 10.
Step 4: Choose the Correct Type
The final step in choosing the right respirator is picking the correct type for your needs. Start by searching for RPEs that meet the APF level. Then, consider the activity level of each worker.
As you start looking at the different types of RPEs available, you’ll also want to consider any other equipment or safety equipment your workers wear. Some RPE won’t fit with other safety equipment like glasses or hard hats.
All ABC Company’s welders wear safety glasses, and so along with searching for respirators with an APF of 10, the safety manager should look for RPEs compatible with glasses. The welders of ABC Company can now safely perform their job duties.
Types of Filters and Cartridges
Part of picking the right respirator is choosing the correct filter for your needs. Most RPEs have one of three types of filters and cartridges—particles, gas/vapor, or combined. All filters and cartridges come with a series letter that designates the type of hazard it protects against.
- Type P—Particles
- Type A—Organic gases and vapors
- Type B—Inorganic gases and vapors
- Type E—Sulphur dioxide and other acid gases
- Type K—Ammonia and organic ammonia derivatives
- Type Hg—Mercury
- Type NO—Oxides of nitrogen
- Type AX—Organic gases and vapors
- Type SX—Filters against specific substances
Particle filters help remove only aerosols such as dusts, mists, fumes, smoke, mold, and bacteria. Gas/vapor filters and cartridges only filter gas or vapors. NIOSH classifies gas and vapors cartridges into a coded color system that makes it easier to know what specific cartridge to purchase based on what gases or vapors are in your workers’ atmosphere. Combined filters and cartridges filter out everything — particles, gas, and vapors.
| Contaminant | Color Coding |
| Acid gases | White |
| Hydrocyanic acid gas | White with 1/2 inch green stripe completely around the canister near the bottom. |
| Chlorine gas | White with 1/2 inch yellow stripe completely around the canister near the bottom. |
| Organic vapors | Black |
| Ammonia gas | Green |
| Acid gases and ammonia gas | Green with 1/2 inch white stripe completely around the canister near the bottom. |
| Carbon monoxide | Blue |
| Acid gases & organic vapors | Yellow |
| Hydrocyanic acid gas and chloropicrin vapor | Yellow with 1/2 inch blue stripe completely around the canister near the bottom. |
| Acid gases, organic vapors, and ammonia gases | Brown |
| Radioactive materials, except tritium & noble gases | Purple (magenta) |
| Pesticides | Organic vapor canister plus a particulate filter |
| Multi-Contaminant and CBRN agent | Olive |
| Any particulates – P100 | Purple |
| Any particulates – P95, P99, R95, R99, R100 | Orange |
| Any particulates free of oil – N95, N99, or N100 | Teal |
Respiratory Protection Standards and Resources
After a company has gone through the steps to figure out what respirators it needs, it should then learn and follow the rules and standards governing them.
ANSI/ASSP Z88.2: Employees use this standard from ANSI/ASSP to find the minimum accepted respirator use practices. It also offers guidance on choosing the right respirator, using and maintaining respirators, and setting up a respirator program.
29 CFR 1910.134: This standard from OSHA outlines all the requirements for employers and employees for RPE usage. OSHA also has a webpage for its Respiratory Protection Standard, including guidance, training videos, and other resources.
National Institute for Occupational Safety and Health (NIOSH) 42 CFR Part 84: NIOSH sets recommendations for respirator use, laid out in regulation 42 CFR Part 84. These regulations set up the requirements manufacturers must meet to receive NIOSH approval for its respirators.
Federal Drug Administration: These guidelines from the FDA cover mainly respirators, surgical masks, and face masks used in health care settings. Some of the policies also apply to industrial environments.
You’re Ready to Get Started with Respiratory Protection
Respiratory hazards abound in any work setting. Because so many respiratory hazards are almost invisible, it’s vital to be exacting when putting together a respiratory program. Matching your respiratory protection with the hazards is critical for preventing injury and long-term workplace illnesses.
Take your time researching and educating yourself on RPE, starting with authority organizations like OSHA and NIOSH. These organizations have set up guidelines and standards to help guide your choices and walk you through the process of keeping your employees safe.
And if you’re still unsure whether your RPE arsenal matches your organization’s needs, don’t be afraid to talk to the respiratory protection manufacturers. They offer a wealth of resources and are always willing to point you in the right direction, even if it’s to a competing product.
Are you ready for more? Head over to Part 2 of this series to learn more about the components of a respiratory program.
