When conducting a clearance inspection, when should sampling be performed after cleaning?

In the context of a clearance inspection, sampling should be performed no sooner than one hour after cleaning to ensure that any remaining contaminants have had adequate time to settle. This waiting period allows for airborne particles or residues that may have been disturbed during cleaning to fall and settle, providing more accurate results during sampling. Performing sampling too soon, such as immediately or within a short time frame after cleaning, may lead to falsely elevated readings of contamination, as newly disturbed dust or particles could still be suspended in the air or on surfaces.

Waiting for at least one hour helps to stabilize the environment, allowing for a true indication of surface cleanliness and contamination levels. This timeframe is commonly accepted in risk assessment practices to ensure that the conditions for testing reflect the true state of cleanliness following remediation or cleaning efforts.