Sets out the principles of respiratory protection. Provides information concerning the effects on the body and protection from harmful substances and atmospheres deficient in oxygen. Offers guidance on considerations critical to the correct selection, use and maintenance of respirators specified in AS/NZS 1716. Advice on the range of protection factors and the level of protection provided by different respiratory devices is covered. Gives guidance on hazard reduction and respiratory protection programs. This Standard does not deal with the special problems associated with underwater breathing, use of respirators in aircraft or life support respirators for medical or resuscitation purposes.