Which option correctly states the outside concrete dust clearance?

Which option correctly states the outside concrete dust clearance?

• A. Window wells 400 ug/ft2
• B. Outside concrete 800 ug/ft2
• C. Both are the same clearance
• D. Neither applies

Answer: (B)

In post-abatement clearance, different outside surfaces have different dust-concentration limits measured in µg per ft2. For exterior concrete, the clearance threshold is 800 µg/ft2, meaning dust on outside concrete should be cleaned down to or below that level. Window wells are treated as a separate surface category with a lower threshold, 400 µg/ft2. Therefore, the correct statement is that outside concrete dust clearance is 800 µg/ft2. The option stating 400 µg/ft2 for window wells is a different surface category, not the exterior concrete, and the idea that both are the same or that neither applies isn’t accurate.

In post-abatement clearance, different outside surfaces have different dust-concentration limits measured in µg per ft2. For exterior concrete, the clearance threshold is 800 µg/ft2, meaning dust on outside concrete should be cleaned down to or below that level. Window wells are treated as a separate surface category with a lower threshold, 400 µg/ft2. Therefore, the correct statement is that outside concrete dust clearance is 800 µg/ft2. The option stating 400 µg/ft2 for window wells is a different surface category, not the exterior concrete, and the idea that both are the same or that neither applies isn’t accurate.