Answer to Question #4292 Submitted to "Ask the Experts"

Q

I am an architect who is involved with laboratory planning. I plan labs related to many fields—medical, pharmaceutical, and college.

Different clients have varying degrees of radiation usage expertise. Some clients have extensive in-house expertise and other clients have none. I will never become an expert on this topic, but some knowledge on my part would be beneficial.

Many of the labs I plan use radionuclides. The issues that come up are:

What quantity of radioisotopes can be used in a laboratory space? When should a fume hood be used for radionuclide work? When would a fume hood with a stainless steel interior be required? (Standard fume hoods do not have a stainless steel surface.) When should a replaceable filter on a dedicated fume hood exhaust be used?
         
I am somewhat familiar with the Occupational Safety and Health Administration (OSHA) regulations regarding exposure limits. I also located a document from a National Institute of Environmental Health Sciences safety guide which breaks labs down into three types: Type C, B, and A (A type having the most stringent requirements).

Do states generally have regulations regarding this topic or are the Nuclear Regulatory Commission and OSHA the source of most of the regulations?

Any guidance on how to approach these issues would be helpful.

A

Most of the questions that you ask are somewhat general. A very good reference that answers your questions, is a technical book prepared by the National Research Council, Prudent Practices in the Laboratory Handling and Disposal of Chemicals (including radionuclides), National Academy Press, Washington, DC, 1995, and its associated references. This book is available on line (free) at the National Academies Press Web site. Specifically refer to Chapters 3 and 8 of this book. I will try to address your specific questions.

Q: What quantity of radionuclides can be used in a laboratory space?
A: The quantity of radionuclides that can be used in a laboratory depends upon, to mention only a few items: (1) the radionuclides used, (2) the emitted radiations, (3) the chemical and physical form of the radionuclides, (4) the design of the laboratory shielding and ventilation systems, etc. For example, a lab with four-foot thick concrete cell walls can handle many more curies of ⁶⁰Co than one with conventional walls; or a lab without a specially designed ventilation system could handle sealed sources of radioactive material but could not handle volatile radioactive materials.

Q: When should a fume hood be used for radionuclide work?
A: A fume hood is a process or engineering control used to prevent the workers from exceeding their annual limit of intake of radionuclides. See 10 CFR 20.1701 and 10 CFR 20, Appendix B, at the NRC Web site. The use of a fume hood, glove box, or general area filtered ventilation, depends upon the variables presented earlier.

Q: When would a fume hood with a stainless steel interior be required? (Standard fume hoods do not have a stainless steel surface).
A: A stainless steel interior and exhaust ducting should be used if corrosive materials will be present, although other corrosion resistant fume hood interiors and ducting materials may be used.

Q: When should a replaceable filter on a dedicated fume hood exhaust be used?
A: All filters (e.g., pre-filters, high-efficiency air-particulate filters, activated-charcoal filters, etc.) should be designed to be replaceable. They will fill up, wear out, or become outdated at some time.

Q: I am somewhat familiar with the Occupational Safety and Health Administration (OSHA) regulations regarding exposure limits. I also located a document from a National Institute of Environmental Health Sciences safety guide, which breaks labs down into three types: Type C, B, and A (A type having the most stringent requirements). Do states generally have regulations regarding this topic or are the Nuclear Regulatory Commission (NRC) and OSHA the source of most of the regulations?
A: The states, in most cases, mirror the NRC and OSHA regulations, but you should check with the state's regulatory authorities to see if their regulations are stricter than the comparable federal regulations.

John P. Hageman, MS, CHP