The purpose of a respirator is to prevent the inhalation of harmful airborne substances and/or an oxygen-deficient atmosphere. A respirator is designed as an enclosure that covers the nose and mouth or the entire face or head.
Respirators are available in many types, models, and sizes from several manufacturers for a variety of applications. Different types of respirators are designed to provide different levels of protection and to protect against different hazards.
The type of respirator to be used depends on several considerations:
When information regarding the exposure is limited, the decision should rely more heavily on professional judgment and more protective respirators may be selected for use.
Each facility’s written policies and training programs should specify whom to contact for questions or additional information.
Particulates: These are airborne particles such as dust, fibers, fumes, mists, soot, and smoke. Some are so small they can only be seen with an electron microscope. The diameter of a particulate is usually measured in micrometers (one micrometer equals 1/1,000 millimeter or 1/25,400 inch). Particles with diameters under 10 micrometers are more likely to enter the respiratory system.
Gas and vapors: Gases can spread freely in the air. Vapors are the gaseous states of substances that are liquids or solids at room temperature. Gases and vapors are classified by their chemical forms.
Biological organisms: These include bacteria, viruses, fungi, and other living organisms that can cause respiratory infections.
Oxygen-deficient atmosphere: Normal air has an oxygen concentration of 20.8 percent by volume. When the concentration drops below 19.5 percent, the air is oxygen deficient and considered immediately dangerous to life and health (IDLH). The harmful effects of oxygen deficiency include impaired thinking and coordination, unconsciousness, and death.
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.
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 is 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.
When using a non-powered air-purifying respirator, the user operates it simply by breathing.
There are basically three types of non-powered APRs:
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.
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:
SCBAs have a full facepiece with an Assigned Protection Factor (APF) of 10,000. APFs are used to select the appropriate class of respirators that will provide the necessary level of protection.
One important distinction that must be made when discussing respirator use is the difference between respirators and facemasks. Facemasks include surgical masks, which are fluid resistant, and procedure or isolation masks which are not fluid resistant.
While some people may call both respirators and facemasks "masks," this is incorrect as they are very different in their design, performance, and purpose.
Only dust masks certified by NIOSH are considered respirators and are covered under 1910.134 rules. A NIOSH-certified dust 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 helps to explain the differences between respirators and facemasks.
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:
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.
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:
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:
The program administrator should maintain an adequate supply of the appropriate cleaning and disinfecting agents at the cleaning station.
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:
A canister or cartridge is a container with a filter, sorbent, or catalyst, or combination of these items, which removes specific contaminants from the air passed through the container. The employer must ensure that all filters, cartridges and canisters used in the workplace are labeled and color coded with the NIOSH approval label and that the label is not removed and remains legible.
To fulfill these requirements, you should adopt appropriate procedures for ensuring that:
What is on the label: The label clearly states the class of contaminants for which the filter, cartridge, or canister may be used (e.g., permissible particulate respirator filter for dusts, fumes and mists, including asbestos-containing dusts and mists and radionuclides. The NIOSH certification number and any limitations or precautions are also included on the label.
Purpose of the label: The NIOSH label serves several purposes. It ensures selection of the appropriate cartridge/canister for the contaminants found in the workplace. Also, it permits the employee using the respirator to check and confirm that the respirator has the appropriate filters before the respirator is used. The color coding scheme allows fellow employees, supervisors and the respiratory protection program administrator to readily determine that the worker is using the appropriate filter.
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This U.S. Department of Labor video covers respirator safety. When you must wear a respirator to protect yourself against airborne contaminants in your workplace, it is very important to follow proper procedures for putting it on and taking it off.