Ventilation Considerations

Facilities performing procedures that involve airborne radionuclides shall be equipped with ventilation that will limit air concentrations to levels that are ALARA and are less than occupational exposure limits. Ventilation systems shall prevent the escape of the airborne contaminants to adjacent non-use areas such that air concentrations in those areas do not exceed those allowed for unrestricted areas.

 

State of California, Department of Health Services, RH 2010 4/90

10 CFR 20, Appendix B

 

Hood inserts are only permitted for iodination procedures specifically approved by the Radiation Safety Officer.

 

NCRP Report, No. 127, Section 4.5

 

Nuclear air cleaning (filtration) systems on major installations shall be designed in accordance with ASME N509 or AG-1, and should be designed in accordance with N509 and AG-1 whenever possible for all installations. The radiation exposure of individuals from the radioactive materials retained on the filter(s) shall be evaluated. Each filter stage shall be designed and located to facilitate independent testing in accordance with ASME N510 or AG-1. HEPA filters used in the last stage of a system just prior to discharge into occupied locations or the environment shall comply with DOE-STD-3020-97 (i.e., will be "nuclear grade").

Each filter stage should be designed and located to facilitate independent testing according to applicable standards. Proper design will allow the filters to be changed easily while minimizing the potential for release of radioactivity and worker exposure. Push-through, bag-in/bag-out systems are preferable. While closed-face filters appear to be convenient to use, proper in-place testing is virtually impossible, so they should not be used whenever the filter will be subjected to in-place testing. Higher-efficiency filters, such as ULPA filters, are available, but they are not as rugged as a nuclear-grade HEPA filter, and they should not be used for nuclear air cleaning. It is noted that AG-1 is supplanting N509 and N510.

 

NCRP Report, No. 127, Section 4.5

DOE-STD-3020-97

ASME AG-1

ASME N509

ASME N510