Any equipment used in research and potentially contaminated with radioactive material must be surveyed prior to repair to determine if it is free of contamination, including fume hoods, biological cabinets, centrifuges, etc.
"Free of contamination" means that the activity on equipment should be less than 100 uCi/100 cm2 based on a wipe test of the surface. The wipe test should be analyzed by a scintillation counter set to detect the isotope/s used in the laboratory.
There are two possible scenarios for the repair of equipment:
- Engineering or a vendor will come to the laboratory to perform the repair, or
- The equipment will be shipped to a vendor or manufacturer for repair.
The survey should consist of:
- monitoring with a geiger counter for gamma emitters, and high energy beta emitters, and
- a wipe test survey to monitor for all radioisotopes used in the equipment.
You should document the results of the survey, including the print-out from the liquid scintillation counter. If you find contamination you will need to decontaminate the equipment with decon spray and paper towels. You then re-survey the equipment and confirm it is clean. Otherwise, if it is still contaminated, decontaminate it a second time. Save survey results from your re-survey attempts to show that the equipment is clean. If after three attempts you are unsuccessful, contact Radiation Safety for assistance.
Example 1 (Fume Hood Repair)*: If you need to have a fume hood repaired by Engineering, you should remove any potentially contaminated items from the hood. You should then monitor it with a geiger counter for contamination and perform a wipe test on its surfaces. The wipe test should include the front edge of the fume hood, the work area, three sides, and the sash. It would be a good idea to do the floor in front of the hood as well. If you find contamination you will need to decontaminate the hood and confirm it is clean by conducting another survey. Repeat the process of decontaminating and surveying until you find the fume hood to be clean. Save the print-outs from the liquid scintillation counter to document that it is clean. Once the fume hood is clean, the Safety Department needs to clear the fume hood prior to Engineering performing the repairs.
*Note: This is the procedure for any equipment to be repaired, moved or discarded.
Example 2 (Centrifuge Repair): If you need to ship a contaminated centrifuge back to the manufacturer for repair you will need to survey it and possibly decontaminate it before hand. Frequently, the company will ask that you sign a form confirming that the item is free of contamination. So it is important that you have documentation that you surveyed the item prior to shipping it. If you find contamination you will need to decontaminate it thoroughly. You may need to remove the rotor to clean it and the inside of the centrifuge. You may also need to soak the rotor to remove the contamination.
Note: There are civil penalties and fines for shipping contaminated equipment to a manufacturer.
If you need guidance to decontaminate any equipment feel free to contact Radiation Safety at x2243.