Respiration - 411

With so many different respirators and uses, it is no wonder we get so many questions about selecting the correct one.  After all, this really could be the difference between life and death.

Below you will find some basic information on respirators and respiration equipment.  While this is meant to assist you in selecting the correct equipment you should always consult a qualified professional before using any safety equipment.  Follow manufacturer's instructions and recommendations.  Often times your company will have a safety director that can answer your questions and provide the right equipment.

A respirator is a device that protects you from inhaling dangerous substances, such as chemicals and infectious particles.  Respirators work by either filtering particles from the air, chemically cleaning (purifying) the air, or supplying clean air from an outside source.

Types of Respirators:

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 "airpurifying respirators" because they clean particles out of the air as you breathe.

Particulate respirators:

Filter out dusts, fumes and mists.
Are usually disposable dust masks or respirators with disposable filters.
Must be replaced when they become discolored, damaged, or clogged.
Examples: filtering facepiece or elastomeric respirator.

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.

Gas masks are effective only if used with the correct cartridge or filter (these terms are often used interchangeably) for a particular biological or chemical substance. Selecting the proper filter can be a complicated process. There are cartridges available that protect against more than one hazard, but there is no "all-in-one" cartridge that protects against all substances. It is important to know what hazards you will face in order to be certain you are choosing the right filters/cartridges.
Chemical Cartridge/Gas Mask respirator: 
Uses replaceable chemical cartridges or canisters to remove the contaminant.
Are color-coded to help you select the right one.
May require more than one cartridge to protect against multiple hazards.

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)

Self-Contained Breathing Apparatus (SCBA) is the 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).
Self-Contained Breathing Apparatus:
Provide clean air from a portable air tank when the air around you is simply too dangerous to breathe.

All of these respirators (except for the "dust masks" or filtering face pieces) are available in either half-mask or full-face pieces.

Fit Testing
Fit testing is required for mandatory use of all tight-fitting facepieces and recommended for voluntary use. OSHA 1910.134(f) states: “The employer shall ensure that an employee using a tight-fitting facepiece respirator is fit tested prior to initial use of the respirator, whenever a different respirator facepiece (size, style, model or make) is used, and at least annually thereafter.



Training
Training is required for mandatory use and recommended for voluntary use of respirators. OSHA 1910.134(k) states: “This paragraph requires the employer to provide effective training to employees who are required to use respirators. The training must be comprehensive, understandable, and recur annually and more often if necessary.

N-Series Filters: These filters are restricted to use in those atmospheres free of oil aerosols. They may be used for any solid or liquid airborne particulate hazard that does not contain oil. Generally these filters should be used and reused subject only to considerations of hygiene, damage, and increased breathing resistance.
 N95 Particulate Filter -At least 95% filter efficient when tested with ~0.3 µm NaCl aerosol.
 N100 Particulate Filter -At least 99.97% filter efficient when tested with ~0.3 µm NaCl aerosol.

R-Series Filters: A filter intended for removal of any particle including oilbased liquid aerosol. They may be used for any solid or liquid airborne particulate hazard. If the atmosphere contains oil, the R-series filter should be used only for a single shift (or for 8 hours of continuous or intermittent use).
R95 Particulate Filter -At least 95% filter efficient when tested with ~0.3 µm DOP (Dioctyl Phthalate) aerosol.

P-Series Filters: A filter intended for removal of any particle including oil-based liquid aerosols. They may be used for any solid or liquid particulate airborne hazard. NIOSH requires that respirator manufacturers establish time-use limitations for all P-series filters. 
Sources:
https://www.osha.gov/dts/shib/respiratory_protection_bulletin_2011.html
https://multimedia.3m.com/mws/media/639110O/3m-respirator-selection-guide.pdf