respiratory protection should be worn when there is a potential to exceed the exposure limit requirements or guidelines.
if there are no applicable exposure limit requirements or guidelines, use an approved respirator.
when respiratory protection is required, use an approved positive-pressure self-contained breathing breathing apparatus or positive-pressure airline with auxiliary self-contained air supply.
for emergency conditions, use an approved positive-pressure self-contained breathing apparatus.
in confined or poorly ventilated areas, use an approved self-contained breathing apparatus or positive pressure air line with auxiliary self-contained air supply.