Radiological Contamination Surveys

State and federal regulations require surveys of public areas and areas where radioactive materials are used to detect contamination and measure radiation levels.

Routine surveys are an important part of the overall radiation safety program in a laboratory. Surveys provide a direct measure of spilled radioactive material and can indicate the radiation hazard of an experiment. It is vital that individuals working with radioactive materials are aware of accepted procedures for performing radiation surveys. EH&S’s Radiation Safety team conducts contamination surveys in areas where radioactive materials are used, including storage and waste facilities, to detect contamination and control exposure to radioactive material.

What you need to know about surveys

What is a survey?

A survey is an evaluation of work areas, instruments and apparatus, floors, sinks, faucet handles, drawer fronts, doorknobs, telephones, light switches, refrigerators and other surfaces for the presence of radioactive contamination.

The following methods can be used to perform a survey:

Survey meter scan
Wipe test

What is contamination?

There are two types of contamination, “removable” and “fixed.”

Removable contamination can be wiped off a surface or object, like dust on a piece of furniture. Removable contamination can be discovered by wipe tests and, in some situations, by use of a survey meter. If contamination is present in large enough quantities and is removable, it may also be detected with a survey meter when a wipe from the surface is placed near the probe.

Fixed contamination has become bound by chemical or other means to the surface upon which it was deposited. This form of contamination can only be detected by a survey meter. Because it is fixed to the surface, a wipe test will indicate no activity. A meter survey may indicate whether large quantities are present on the surface.

How often must surveys be performed?

An operating survey meter should be within reach whenever working with radioactivity other than tritium (H-3). Individuals should survey themselves and their work areas on an “as used” or daily basis. We recommend that you conduct frequent surveys of hands and other skin areas, lab coats and shoes during and after use of radioactive material to identify contamination, so exposures can be avoided. Documented wipe tests and meter surveys must be performed at least monthly, but may be needed more often, depending on the radioisotope used.

What survey documentation are required?

All documentation of surveys must include the following information:

Date
Name of person performing the survey
Room number and floor plan map
Location number, indicating on the map where the wipe test or meter reading was taken
Wipe test results including background
Survey meter scan results including background
If applicable, wipe test and survey meter results following decontamination

Use the Lab Survey Record to document the results of each survey.