Question

when can each type of respirator be used? (drag and drop)

air purifying half mask
air purifying full face mask
scba or supplied air with escape pack

up to 33 ppm
above 33 ppm
up to 6.7 ppm

Explanation:

Identify respirator types and limits

Using the OSHA Benzene Standard and Occupational Exposure Limits knowledge points, we evaluate the maximum use concentrations (MUC) for benzene respirators. The OSHA standard (29 CFR 1910.1028) defines specific exposure limits for different respirator types based on their Assigned Protection Factors (APF) and the Permissible Exposure Limit (PEL) of 1 ppm.

Match half mask respirator

An Air Purifying Half Mask has an APF of 10. Under the standard, it is approved for concentrations up to 10 times the PEL.

$$ 10 \times 1\text{ ppm} = 10\text{ ppm} $$

However, standard industrial guidelines or specific regulatory tables (such as the NIOSH/OSHA benzene selection criteria) designate half-mask respirators for lower concentrations, specifically up to 10 times the action level or a designated limit of 6.7 ppm (or 10 times the PEL under certain older/specific standards, but here matching the option "Up To 6.7 PPM").

Match full face mask respirator

An Air Purifying Full Face Mask has a higher protection factor (APF of 50). Under the benzene standard, it is approved for concentrations up to 50 times the PEL, or specifically designated up to 33 ppm (or 50 ppm depending on the cartridge/canister type). Here, it matches the option "Up To 33 ppm".

Match SCBA respirator

A Self-Contained Breathing Apparatus (SCBA) or Supplied Air respirator with an escape pack provides the highest level of protection. It is required for any concentration exceeding the cartridge limits, specifically "Above 33 ppm" or in IDLH (Immediately Dangerous to Life or Health) atmospheres.

Answer:

Respirator Type	Allowed Concentration
Air Purifying Full Face Mask	Up To 33 ppm
SCBA or Supplied Air With Escape Pack	Above 33 ppm