Respirators are classified by the type of hazard they protect against, their APF and the specific substance(s) they’re approved for. There are other ways that you may also commonly see respirators classified as well, such as:

Negative-Pressure

Negative-pressure respirators rely on the wearer to pull air in through cartridges or filter. This has the potential to put a strain on the wearer, which is why medical evaluations are important and recommended.*

*As per section 6, Medical and Physical considerations, AS/NZS 1715

Disposable respirators, also known as filtering facepieces, are used to help protect against some particulate hazards. They’re lightweight and require no maintenance since they’re discarded after use.

Reusable respirators can be used with particulate filters, gas and vapor cartridges or combination cartridges, which may need to be replaced on a schedule or as needed.

Half-face respirators cover the lower half of the face, including the nose and mouth.

Full-face respirators cover the eyes and much of the face, and can sometimes replace the need for safety glasses.

Positive Pressure

Positive-pressure respirators do the work of pushing air to the respirator headtop or facepiece; they can either be powered-air, using a battery-powered blower to pull air through a filter, or supplied-air, bringing clean air through a hose from a source outside of the contaminated work area (refer Appendix A, AS/NZS 1715, requirements for air quality for supplied air respirators).

Tight-fitting respirators must be fit-tested when use is required, and users must perform seal checks every time a tight fitting negative pressure respirator – a filtering facepiece or half facepiece respirator - is worn.

Loose-fitting respirators typically have a hood or helmet.

Self-Contained Breathing Apparatus (SCBA)

Self-contained breathing apparatus (SCBA) is classified as a positive pressure supplied air respirator, but is different from all other respiratory equipment in that the user carries the source of the clean air with them in a tank. This type is mainly used for conditions that are unknown or “immediately dangerous to life or health” (IDLH), such as oxygen-deficient atmospheres, when hazards are so concentrated or so toxic they can’t be brought to acceptable levels with other types of respiratory protection, or when you’ve been unable to definitively record the level of hazard in the workplace.

Choose a Cartridge and/or Filter

Understanding the different types of particulate filters and gas and vapour cartridges will help you select the right one.

As per AS/NZS 1715 there are 3 different classes of particulate filters, P1, P2 and P3.

The negative pressure particulate categories are based facepiece coverage. All particulate filtering facepieces that cover the nose and mouth area only can achieve only a P1 or P2 classification. A P3 classification can ONLY be achieved when worn with a full facepiece. 

• Class P1 particulate filters are used against mechanically generated particulates e.g. silica and wood dust.
• Class P2 particulate filters are used for protection against mechanically and thermally generated particulates or both e.g. metal fumes.
• Class P3 particulate filters are used for protection against highly toxic or highly irritant particulates e.g. beryllium (when worn with a full facepiece).
• NOTE: certain contaminants may have specific respiratory selection criteria outside this guide e.g. asbestos.
• Gas and vapour cartridges categories are distinguished by their filter type and class. Refer to AS/NZS 1715 for the complete list of filter types and what they are used for. Some commonly used filter types are:
• Filter type A = Certain organic vapours (boiling point above 65⁰C) from solvents such as those in paints and thinners (cartridge label colour = brown)
• Filter type B = Acid gases such as chlorine, hydrogen sulfide (sulphide) and sulfur dioxide (cartridge label colour = grey)
• Filter type E = Vapours from sulfur dioxide (cartridge colour = yellow)
• Filter type ABE = are suitable for both certain organic vapours/acid gases and sulfur dioxide e.g. solvents, chlorine and sulfur dioxide (cartridge label colour = brown, grey and yellow)
• Filter type K = ammonia gas (cartridge label colour = green)
• Filter type ABEK = are suitable for both certain organic vapours/acid gases, sulfur dioxide and ammonia (cartridge label colour = brown, grey, yellow and green)