United States Nuclear Regulatory Commission - Protecting People and the Environment

U.S. Nuclear Regulatory Commission

U.S. Nuclear Regulatory Commission

Question 405: Regulatory Guide 8.25 (Section C.1.7) states

that "to determine whether the concentration exceeds the

DAC over the short term, the sample collection time should

not exceed one hour. Shorter sample collection times may

be used if desired, but they are not required." a.) Does

this section mean to imply that the duration of a work zone

air sample should not exceed one hour if it may be used to

determine whether an area needs to be posted or otherwise

controlled? b.) Under what circumstances does this one

hour rule apply?



Answer: (a) No. The one-hour criterion applies only for

sampling used "to determine whether the concentration

exceeds the DAC over the short term" (emphasis added).



b) The one-hour criterion is guidance; it is not a "rule."

See answer to (a) regarding the circumstances of

application. (References: Regulatory Guide 8.25, 10 CFR

20.1902).









Page Last Reviewed/Updated Thursday, March 29, 2012