Which method is used to measure fixed contamination on surfaces?

• A. Direct survey/frisking of the surface
• B. Contamination which cannot be removed or transferred easily
• C. Wiping the surface with a cloth or smear
• D. Directing the HEPA discharge over contaminated surfaces

Answer: (A)

Direct survey or frisking the surface is used to measure fixed contamination. By scanning the area with a handheld radiation detector, you assess the radiation from contaminants that are bonded to the surface without removing the surface itself. Fixed contamination won’t come off easily, so a wipe test wouldn’t reliably quantify it; wipe tests are designed to measure removable contamination, not what’s fixed to the surface. Decontamination methods like using HEPA discharge are about removing contamination, not measuring it.