What type of dust sampling technique should be used during a clearance examination?

• A. Collecting soil samples only.
• B. Single-surface dust sampling techniques only.
• C. Multi-surface sampling always required.
• D. Vacuuming from every surface.

Answer: (B)

Clearance testing relies on measuring lead dust directly from the specific surfaces that were disturbed or cleaned, and you do this one surface at a time. Sampling a single surface at a defined area gives you precise, surface-by-surface data, which helps verify that each individual area meets the required lead limit. If you tried to mix or average results from several surfaces, a hot spot could be hidden and you wouldn’t know which surface still exceeds the standard.

That’s why the standard approach uses single-surface dust wipe sampling. Collecting soil samples isn’t appropriate for interior clearance since the focus is on settled dust on interior surfaces. Vacuuming every surface isn’t used for clearance dust sampling because it doesn’t provide the same surface-specific lead data and can disturb or miss the actual surface contamination that needs to be evaluated. Multi-surface sampling isn’t the mandated method for clearance testing, since it risks diluting or masking localized contamination.