Gas/Vapour Filter/Cartridge types
Different Standards have different types, classification and colours for gas/vapour filters/cartridges. See below for a high-level summary of AS/NZS 1715:2009 and AS/NZS ISO 17420.2:2021 types and classes. Refer to the relevant standard for further information.
Under the AS/NZS ISO, the classification of a filtering respiratory protective devices (RPD) is determined by the appropriate combination of the following classes: (protection class) (work rate class) (RI class) (particle filter class and/or gas filter type and class). Additionally filtering RPD may be classified for one or more special applications, as given in AS/NZS ISO 17420-5 to AS/NZS ISO 17420-9
| AS/NZS ISO 17420.2:2021 Table 1 | |||
| Type | Classes | Type Description | Colour |
| OV | 1, 2, 3 or 4 | Organic Vapours with boiling point > 65˚C e.g. Cyclohexane | Blue |
| OG | 1 | Organic Gases with boiling point ≤ 65˚C e.g. Dimethylether | Blue |
| AC | 1, 2, 3 or 4 | Acidic Compounds e.g. Hydrogen Sulfide (H₂S), Chlorine (CL₂), Sulfur Dioxide (SO₂) | Blue |
| BC | 1, 2, 3 or 4 | Basic Compounds e.g. Ammonia (NH₃) | Blue |
| NOX | 1, 2 or 3 | Nitrogen Oxides e.g. Nitrogen Monoxide (NO), Nitrogen dioxide (NO₂) | Blue |
| HG | 1, 2 or 3 | Mercury (Hg) | Blue |
| OZ | 1 | Ozone (O₃) | Blue |
| HCN | 1, 2, 3 or 4 | Hydrogen Cyanide (HCN) | Blue |
| AH | 1 | Arsine (AsH₃) | Blue |
| HF | 1, 2 or 3 | Hydrogen Fluoride (HF) | Blue |
| CD | 1 | Chlorine Dioxide (ClO₂) | Blue |
| ETO | 1, 2 or 3 | Ethylene Oxide ((CH₂)₂O) | Blue |
| FM | 1, 2 or 3 | Formaldehyde (CH₂O) | Blue |
| MB | 1, 2 or 3 | Methyl Bromide (CH₃Br) | Blue |
| CO | Three classes based on time (20 min, 60 min or 180M) | Carbon Monoxide (CO) | Blue |
| PH | 1 or 2 | Phosphine (PH₃) | Blue |
AS/NZS 1715:2009 in Table 4.4 and AS/NZS 1716 specify the different types of gas/vapour filters. The classes are distinguished by their gas absorptive capacity and, in general, by their size and mass
| AS/NZS 1715:2029 Filter Types for Gases and Vapours Table 4.4 | |||
| Type | Classes | Type Description | Colour |
| A | AUS, 1, 2 or 3 | For use against Organic Vapours with boiling point > 65˚C as specified by the manufacturer. | Brown |
| B | AUS, 1, 2 or 3 | For use against Acid and Inorganic gases as specified by the manufacturer e.g. Hydrogen Sulfide (H₂S), Hydrogen Cyanide (HCH), Chlorine (CL₂), | Grey |
| E | 1, 2 or 3 | For use against Sulfur Dioxide (SO₂) and other acid gases as specified by the manufacturer. | Yellow |
| G | – | For use against certain organic compounds with vapour pressures less than 1.3 Pa (0.01 mm Hg) at 25°C as specified by the manufacturer and must have an integral particulate filter with an efficiency at least equivalent to that of a P1 filter. | – |
| K | 1, 2 or 3 | For use against ammonia (NH₃) and organic ammonia derivatives as specified by the manufacturer. | Green |
| Hg | – | For use against metallic mercury (Hg) | Red |
| NO | – | For use against oxides of nitrogen (NO & NO₂) | Blue |
| MB | 2 or 3 | For use against methyl bromide (CH₃Br) | – |
| AX | – | For use against low boiling point organic compounds as specified by
the manufacturer (boiling point ≤65°C). |
Brown |
| Specific Chemical type | – | For use against one or more specific chemicals not falling into any of
the above type descriptions. The filter is identified by the name of that chemical. |
– |
Reference/s for further information and detail:
- AS/NZS 1715:2009 – Selection, use and maintenance – Section 4.2.5
- SA/SNZ TS ISO 17420.2:2023 –Requirements for Filtering RPD – Section 4 and 6.10.1.3
