What is the purpose of interim cleaning in the typical sequence?

• A. Interim cleaning is performed only after clearance sampling.
• B. Interim cleaning is the final cleaning step.
• C. A cleaning step performed after abatement but before clearance sampling to reduce dust.
• D. Interim cleaning involves removing contaminated equipment.

Answer: (C)

Interim cleaning is the cleaning step that happens after abatement work and before clearance sampling. Its purpose is to knock down and remove dust and debris created during abatement so that the clearance samples measure only what remains after abatement, not leftover housekeeping dust. This reduces the risk that the sampling results are skewed by dust that was generated during cleanup rather than by residual contamination, helping ensure the area meets the required clearance criteria. Typical actions include HEPA vacuuming of all surfaces and wet-wiping of horizontal surfaces, followed by removing debris to create a cleaner testing environment. It isn’t the final cleaning step, nor is it performed only after clearance sampling. The main goal is reducing dust to improve the accuracy of the subsequent clearance results.