What is the default minimum number of dust samples required for interior work with no dust containment?

• A. 12 samples
• B. One sample per room equivalent if the unit has less than 4 room equivalents
• C. 6 samples
• D. 3 samples

Answer: (A)

Twelve dust wipe samples form the default minimum because clearance testing is about reliably detecting any remaining lead dust across the interior after work when no containment was used. Without containment, dust can spread more widely, so collecting a larger number of samples improves the chance of catching scattered contamination and provides a more representative assessment of the whole space. The sampling plan typically covers multiple rooms and surfaces (like floors and high-contact areas) to ensure hotspots aren’t missed and the results can be evaluated against the required safety thresholds. Using fewer samples increases the risk of missing elevated levels, which is why a twelve-sample baseline is used as the standard default.