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Respirator Basics

Respirator Types - OSHA
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A respirator is a device that protects you from inhaling dangerous substances, such as chemicals and infectious particles. Respirators are among the most important pieces of protective equipment for working in hazardous environments.

Selecting the right respirator requires an assessment of all the workplace operations, processes or environments that may create a respiratory hazard. The identity of the hazard and its airborne concentrations need to be determined before choosing a respirator. This assessment should be done by experienced safety personnel or by an industrial hygienist.

Respirators work by:

  • filtering particles from the air,
  • chemically cleaning (purifying) the air, or
  • supplying clean air from an outside source.

Respirator Types

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To understand how respirators can be used to protect employees, it is important to understand what a respirator is and what it is not. A respirator protects against respiratory hazards by removing specific air contaminants from the ambient (surrounding) air or by supplying breathable air from a safe source.

Particulate Respirators:Particulate respirators are the simplest, least expensive, and least protective of the respirator types available. These respirators only protect against particles (e.g., dust). They do not protect against chemicals, gases, or vapors, and are intended only for low hazard levels. The commonly known "N-95" filtering facepiece respirator or "dust mask" is one type of particulate respirator, often used in hospitals to protect against infectious agents. Particulate respirators are "air-purifying respirators" because they clean particles out of the air as you breathe.

Chemical Cartridge/Gas Mask Respirator: Gas masks are also known as "air-purifying respirators" because they filter or clean chemical gases out of the air as you breathe. This respirator includes a facepiece or mask, and a cartridge or canister. Straps secure the facepiece to the head. The cartridge may also have a filter to remove particles.

Powered Air-Purifying Respirator (PAPR): Powered air-purifying respirators use a fan to draw air through the filter to the user. They are easier to breathe through; however, they need a fully charged battery to work properly. They use the same type of filters/cartridges as other air-purifying respirators. It is important to know what the hazard is, and how much of it is in the air, in order to select the proper filters/cartridges.

Self-Contained Breathing Apparatus (SCBA) is an atmosphere-supplying respirator commonly used by firefighters. These use their own air tank to supply clean air, so you don't need to worry about filters. They also protect against higher concentrations of dangerous chemicals. However, they are very heavy (30 pounds or more), and require very special training on how to use and to maintain them. Also, the air tanks typically last an hour or less depending upon their rating and your breathing rate (how hard you are breathing).

Air Purifying Respirators (APR)

The air-purifying respirator, or "APR", has an air-purifying filter, cartridge, or canister that removes specific air contaminants, such as particulates, gases, and vapors, or both from the air.

Selecting an appropriate filter, cartridge, or canister can be complicated because there are many types, and none protect against all contaminants. That's why it's necessary to identify each respiratory hazard in your workplace before you select a respirator.

Air-purifying respirators are available in non-powered and powered types. We will discuss these two types of respirators in the next couple sections.

Non-Powered Air-Purifying Respirator (APR)

non-air purifying

When using a non-powered air-purifying respirator, the user operates it simply by breathing.

There are basically three types of non-powered APRs:

  • Half mask/Dust mask
  • Half mask (Elastomeric)
  • Full face piece (Elastomeric)

Key Features

  • elastic face piece covers entire face
  • inspiratory effort of wearer draws ambient air through filter(s) before air is inhaled
  • provides increased protection when used with filters, cartridges, or canisters that remove specific contaminants


  • comparatively light weight
  • does not restrict mobility
  • provides both respiratory and eye protection


  • Does not supply oxygen (cannot be used in low oxygen environments).
  • May only be used when air contaminant level is below the concentration limits of the filter(s).
  • Fit testing required.
  • Some contaminated air can leak into facepiece.
  • Communication can be difficult.

Powered Air-Purifying Respirator (PAPR)

air purifying

This type of respirator has a blower that forces ambient air through one or more filters attached to an inlet covering. The powered type is easier to breathe through than the non-powered type but needs a fully charged battery to work properly.

Key Features

  • Battery powered blower forces contaminated ambient air through air-purifying filters.
  • Purified air is delivered under positive-pressure to facepiece mask, helmet, or hood.
  • Worn when disposable and reusable half mask negative-pressure air-purifying respirators do not provide adequate protection.


  • Provides greater protection than non-powered negative-pressure air-purifying respirators.
  • More comfortable to wear and to breathe compared to non-powered negative-pressure air-purifying respirators.
  • Air delivery to facepiece mask, helmet, or hood ensures that leakage of contaminated air is usually outward.
  • Fit testing is not required.
  • Various chemical cartridges or canisters are available to eliminate chemicals including organic vapors and acid gases.
  • Provides both respiratory and eye protection.


  • bulky and noisy
  • battery dependent
  • not a true positive-pressure device (i.e., some leakage of contaminated air into facepiece mask, helmet, or hood can occur)
  • communication can be difficult

Atmosphere-Supplying Respirators

atmosphere supplying

Atmosphere-supplying respirators are used to provide breathing air from a source independent of the ambient atmosphere. Respirators that supply breathing air are generally used in highly hazardous work environments. It is critical that such respirator systems provide breathing air of optimal quality and that the equipment operates reliably.

The two types of atmosphere-supplying respirators are:

  • Supplied-air respirators (SARs) (also known as airline respirators), receive air from a connecting hose. The source of air is either a pressurized cylinder or an air compressor. Because the employee does not carry the air on his or her back when using a SAR, breathing air can be provided over a longer time period than is the case with an SCBA.
  • Self-contained breathing apparatus (SCBA) units: Air is supplied from a tank (a cylinder of compressed air or oxygen). For this type of respirator, the source of the breathing air is designed to be transported by or with the equipment user.

Supplied-Air Respirator

Donning a Supplied Air Respirator – IUOE NTF
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Key Features

  • Compressed air is delivered from a stationary source (located away from contaminated area) to a half or full facepiece mask via a hose.
  • Worn when negative-pressure and powered air-purifying respirators do not provide adequate protection.


  • Provides high level respiratory protection.
  • Provides positive pressure to mask so almost all leakage is outward.
  • Less bulky and can be used for longer periods than self-contained breathing apparatus.
  • May be easier for hospital personnel to use.
  • Provides both respiratory and eye protection.


  • Length of air hose may limit mobility.
  • Air hose may be a trip hazard.
  • Clean source of breathing air is required.
  • Fit testing is required.
  • Immediately operable emergency escape respirator, escape hood, or escape mask is required.
  • Communication can be difficult.

Self-Contained Breathing Apparatus (SCBA)

engineering control

SCBAs have a full facepiece with an Assigned Protection Factor (APF) of 10,000. Fit testing is required.

Key Features

  • Provides very pure, dry compressed air to full facepiece mask via a hose.
  • Air is exhaled to the environment.
  • By law, this type of respirator must be worn whenever entering environments immediately dangerous to life and health (IDLH) or when information is inadequate to rule out IDLH atmosphere.


  • Provides highest level of respiratory protection.
  • Several different types are available depending on need.
  • Offers improved mobility over Supplied-Air Respirators.
  • Provides both respiratory and eye protection.


  • They are heavy to wear.
  • Limited oxygen supply limits the duration of use.
  • Fit testing is required.
  • Communication can be difficult.

Are Dust Masks Respirators?

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While some people may call both respirators and facemasks "masks," this is incorrect as they are very different in their design, performance, and purpose. One important distinction that must be made when discussing respirator use is the difference between dust masks and respirators.

Dust masks are not NIOSH-approved disposable filtering face pieces. They can be worn for comfort against non-toxic nuisance dusts during activities like mowing, gardening, sweeping and dusting.

Only face masks certified by NIOSH are considered respirators by OSHA and covered under 1910.134 rules.

A NIOSH-certified face mask - called a filtering facepiece - is a tight-fitting, negative pressure, particulate respirator. The particulate filter is the facepiece. Dust masks that don't have NIOSH certification are not respirators. The video to the right discusses these differences in more detail.

Respirator Selection

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Properly selected and used, respirators protect workers from hazards but don’t eliminate hazards. If the respirator fails or is inappropriate for a particular task, the user risks exposure. A respirator can stress a worker’s heart and lungs and present other physical and psychological challenges such as:

  • Breathing through a tight-fitting air-purifying respirator, for example, is harder than breathing ambient air.
  • An atmosphere-supplying self-contained breathing apparatus (SCBA) can increase the user’s heart rate because of its weight.
  • Those with lung diseases or asthma or who have trouble breathing should never use a respirator without the approval of a professionally licensed-health care provider (PLHCP).
  • Those who have vision problems or who are claustrophobic may also be unable to use some respirators.

Effective respiratory protection ensures that workers are medically able to use respirators, that their respirators fit properly, and that they know how to use and care for their respirators.

Respirator Care and Maintenance – OSHA
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Care and Maintenance of Respirators

Employees must clean and inspect their own respirators in accordance with the provisions of the respiratory protection program. Here are some important things to remember:

  • Maintenance involves a thorough visual inspection for cleanliness and defects.
  • Worn or deteriorated parts must be replaced prior to use.
  • No components are to be replaced or repairs made beyond those recommended by the manufacturer.
  • Repairs to regulators or alarms of atmosphere-supplying respirators are to be conducted by the manufacturer.

Cleaning Respirators


Cleaning and sanitizing respirators is necessary to prevent skin irritation and dermatitis. Contaminant build-up on the respirator facepiece seal or within the respirator can reduce the protection because the contaminant is in the breathing zone or has compromised the seal. Contamination can also contribute to the deterioration of the respirator's materials. Also, follow these cleaning best practices:

  • Respirators must be cleaned and disinfected as often as necessary to remain sanitary.
  • Respirators used by more than one employee must be cleaned and disinfected before being used by a different individual.
  • Respirators maintained for escape-only use, as well as respirators used in fit testing and training, must be cleaned and disinfected after each use.

The program manager should maintain an adequate supply of the appropriate cleaning and disinfecting agents at the cleaning station.

Storing Respirators

After inspection, cleaning, and necessary repair, store respirators so that they are not damaged, contaminated, or exposed to dust, sunlight, extreme temperatures, excessive moisture, and damaging chemicals. Follow these procedures to store respirators properly:

  • Store filter cartridges separately from clean respirator face pieces to prevent contamination of the interior of the respirator facepiece from hazardous particulate matter (e.g., lead, asbestos, cadmium, silica) that may have accumulated on the filter cartridge.
  • Store the facepiece and the exhalation valve in a manner that will prevent deformation. To do that, position each respirator so it retains its natural configuration. Synthetic materials and even rubber will warp if stored in an unnatural shape, thus affecting the fitting characteristics of the facepiece.
  • Respirators should be packed or stored so the facepiece and exhalation valve will rest in a normal position and function will not be impaired by the elastomer setting in an abnormal position.


Before beginning this quiz, we highly recommend you review the module material. This quiz is designed to allow you to self-check your comprehension of the module content, but only focuses on key concepts and ideas.

Read each question carefully. Select the best answer, even if more than one answer seems possible. When done, click on the "Get Quiz Answers" button. If you do not answer all the questions, you will receive an error message.

Good luck!

1. Which type of respirator removes contaminants from the ambient air?

2. Which type of respirator supplies air from a safe source other than the ambient air?

3. Which type of respirator is easier to breathe through but needs a fully charged battery to work properly?

4. What is the part of a respirator that forms a protective barrier between the user’s respiratory tract and air contaminants?

5. Filter cartridges must be _____ respirator facepieces that have been cleaned.

Have a great day!

Important! You will receive an "error" message unless all questions are answered.