It’s clearly recognised that we need clean air to survive and that exposure to toxins could cause irreparable damage to our health, but sometimes respiratory risks are not obvious or the damage to human respiratory systems occurs over a longer period of time, which is why choosing suitable respiratory protection is important for long term worker health.

Respiratory protective devices are classifed into two main groups : Air Purifying Respirators (Filtering devices) and Air Supplied Breathing Apparatus.

Where an Immediately Dangerous to Life and Health (IDkH) atmosphere is identifed, air purifying respirators/ (Filtering Devices) are not suitable and self-contained and/or air supplied demand breathing apparatus.

Must be used, due to the risk of oxygen displacing gases or other hazards where a filter may not provide appropriate protection from the hazard.

Air Purifying Respirators (APR) filter or purify air when drawn or inhaled through the filter media.

Air Purifying Respirators (Filtering devices) are suitable in :

  • Areas where contaminant levels are low and the contaminant is known.
  • Suitable filters are available.
  • Other engineering controls are not possible.

Air Purifying Respirators (Filtering Devices) are NOT suitable in :

  • IDkH areas.
  • Low oxygen areas (less than 19%).
  • Where contaminants are unknown.
  • Where contaminants have poor warning properties (e.g. odourless gases).

Options available are :

  • Disposable respirator.
  • Half face.

According to NIOSH (US Standard) and EN Standard disposable respirator have different classification. In NIOSH 42 CFR 84 have 2 classification, 1 is working environment and 1 is filter efficiency.

Particulate Filters are classifed as P1, P2 or P3 :

  • P1 filters handle mechanically generated particles down to 0.5 microns or 80% efficiency.
  • P2 filters handle mechanical thermally generated particles down to 0.2 microns or 94% efficiency.
  • P3 filters handle mechanical thermally generated particles down to 0.2 micron or 99.95% efficiency.

For Gas Filter mask :

The life of a gas filters is dependent upon temperature, humidity, concentration of the contaminant, the class of filters and the rate of breathing of the wearer. Filters should be replaced on a regular basis in accordance with an established filter replacement schedule identifed in the initial risk assessment. AS/NZS 1716: 2012 recommends discarding your filters when any one of the following conditions exists :

  • The filter becomes difficult to breathe through.
  • Breakthrough gas occurs; indicated by smell or taste or according to the filters replacement schedule identifed during the risk assessment.
  • 6 months has passed since sealed filters package has been opened.
  • The expiry date on the filters has passed.

In some instances, depending on the type of chemical hazard, filters must be changed out after each shift, if filters are to be re-used they should be stored in a sealed plastic bag or box.