The boiling point of an organic vapour contaminant matters in respirator selection because it directly affects how easily that organic vapour breaks through a gas/vapour cartridge/filter. Lower‑boiling‑point vapours behave more like gases—they move faster, evaporate more readily, and migrate through the gas/vapour filter/cartridge media (even when not in use).

Organic compounds with a boiling point  ≤65˚C at atmospheric pressure are considered to have low boiling points and there are specific filters/cartridge classification for these.  This category of filter intended to be used solely against low boiling point organic compounds during a single eight-hour shift, where the total logged period of use does not exceed the minimum specified absorption time of the filter. It is intended that the filter be discarded after such a period of use. In AS/NZS 1715/1716 this is an AX class and in AS/NZS ISO 16973:2023 it is an OG (Organic Gas) class. Refer to the product manufacturer for specific limitations and chemicals. Supplied air respirators may be required low boiling point organics instead of a AX/OG filter/cartridge.

The boiling point is a quick indicator of volatility, and volatility determines how long a respirator cartridge can protect you. Lower boiling point = higher volatility = faster breakthrough.

Some examples of low boiling point organics are (but not limited to)

  • Acetone 56˚C
  • Dimethylether 35˚C
  • Ethyl chloride 12˚C
  • Vinylchloride -13˚C
  • Acetaldehyde 20˚C
  • Ethylene oxide 10˚C
  • Pentane 36˚C

Reference/s for further information and detail: