Work rate assessment is a new aspect to respiratory protective device (RPD) from AS/NZS 1715 to AS/NZS ISO Selection use and maintenance series.

AS/NZS 1715 Section 4.3.3 covers the need as part of the task related selection factors to consider the degree of activity and mobility requirements. But also, for more strenuous activity being undertaken the consideration of supplied air RPR or powered air purifying respirator (PAPR) may be more comfortable.

There are many physiological effects associated with the of RPD such as:

  • Stressors
    • Environmental – Temperature, humidity, airborne contaminants, clothing
    • Respiratory Protection – breathing resistance, comfort/fit, wear time
    • Work demands – Activity and duration, work rate
  • Individual Characteristics (Anthropometric & Physiological)
    • Age/hydration
    • Cardiovascular function
    • Respiratory Function
    • Acclimatisation
  • Strain Responses
    • Cardiovascular
    • Thermoregulatory
    • Psycho-physiological effects

The area was a key area of consideration in the development of the ISO RPD standards now locally adopted in Australia and New Zealand as part of the AS/NZS ISO 16976 Human factors Series which is part of the underpinning science of the AS/NZS ISO RPD standards.

There are 4 work rates classes in SA/SNZ TS ISO 16973, which are condensed from the 8 ISO 8996 Metabolic classes. Respirators tested under the AS/NZS ISO framework may be tested to 1 or more different work rates (as selected by the manufacturer), meaning the same respirator combination can have different ratings for the different work rates. High work rates mean higher flow rates the filters are tested to and the combination tested on a simulated breathing machine at the different breathing rates.

SA/NZS TS ISO 16973.1:2023 Section 7.3.3.4 details these work rates and examples of corresponding activities as part of the selection process. Refer to Work Rates and Examples activities – RESP-FIT RPD Online as part of the Respirator Selection tool process

Reference/s for further information and detail:

  • AS/NZS 1715:2009 – Selection, use and maintenance – Section 4.3.3
  • SA/SNZ TS ISO 16975.1:2023 – Selection, use and maintenance – Section 7.3.3.4