RPD Selection Information

The selection process needs to include an assessment of the likely effects of the Respiratory Protective Devices (RPD) upon the wearer when deployed in extreme temperature or humidity conditions.

Extreme climatic conditions (hot & cold) can affect the performance of RPD or wearer comfort, both of which can lead to a loss of protection and reduction in service life of the RPD. Elements of the environment that should be considered are the range of temperature and humidity, wind velocity and increased or decreased pressure in the environment in which the RPD is to be used.  These elements might have an impact on the core body temperature of the wearer, which may reduce the amount of time the RPD wearer can work.

Extreme high temperatures can affect the performance of RPD in a number of ways, some of which could result in a reduction or even loss of respiratory protection. It is therefore essential that users consult the RPD manufacturer where RPD is to be deployed in extreme high temperatures. Respirator usage in hot environments can put additional stress on the user. The stress may be minimised by using a respirator with low breathing resistance. In this respect, an air-line respirator equipped with a cooling system could be considered. Evaluating different designs which retain sufficient respiratory protection, may mitigate such hazards and increase comfort afforded to the wearer. Some examples of how RPD can be affected by high temperatures are as follows (but not limited to):

• Materials such as plastics commonly used in RPD may melt or soften.
• The performance and service life of gas and vapour filters may be degraded.
• Performance of electrochemical batteries used in RPD and other equipment have maximum temperature limits, potentially affecting airflow and duration.

Extreme low temperatures can also affect the performance of RPD in a number of ways some of which could result in a reduction or even loss of respiratory protection. It is therefore essential that users consult the RPD manufacturer where RPD is to be deployed in extreme low temperatures. Some examples of how RPD can be affected by low temperatures are as follows (but not limited to)

• Respiratory interfaces and parts of respiratory interfaces such as sealing surfaces and flexible hoods can become more brittle and crack, or less flexible potentially causing fit or comfort problems. 
• Components of the breathable gas supply chain such as hoses and tubes can also become more brittle and crack, or being less flexible, become unwieldy causing comfort and fitting problems.
• Components such as valves may not function effectively under very low temperatures.
• Any moisture in the compressed breathing gas or exhaled breath can condense, causing flow restrictions or other defects. In extreme cold, moisture from exhaled air can freeze in valve assemblies rendering them ineffective.
• Performance of some supplied breathable gas RPD can be adversely affected by low temperature conditions.
• Performance of electrochemical batteries used in RPD and other equipment falls off rapidly with decreasing temperature, potentially affecting airflow and duration.
• Fogging of lenses may be increased at low temperatures

Reference/s for further information and detail:

• AS/NZS 1715:2009 – Selection, use and maintenance – Section 4.3.5
• SA/SNZ TS ISO 16975.1:2023 – Selection, use and maintenance – Section 7.3.3.9 Annex D D.5