respiratory protection -Reply

[Stephen McGuire <SAM2@nrc.gov>]

With regard to a time for averaging airborne concentrations, the NRC's Regulatory
Guide 8.25, "Air Sampling in the Workplace," states (in paragraph C.1.7), "To
determine whether the concentration exceeds the DAC over the short term, the
sample collection time should not exceed 1 hour.  Shorter collection times may be
used if required, but they are not required."

Thus, a 1-hour sampling time is acceptable for measuring peak concentrations.