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