When enclosure, removal, or encapsulation is completed during an abatement, clearance air sampling must be performed to ensure that fiber levels in the air within the containment area do not exceed the clearance standard or alternative clearance standard.
The asbestos containment area must not be reoccupied until compliance with subitem (1) or (2) is achieved:
each of five clearance air samples, collected according to subpart 2, is less than or equal to the clearance standard or the alternative clearance standard; or
for a small residential abatement each of three clearance air samples, collected according to subpart 2, are less than or equal to the clearance standard.
If any clearance air sample result exceeds the clearance standard or alternative clearance standard, or any clearance air sample is too heavily loaded to be quantitatively analyzed, the containment area must be recleaned and reinspected according to part 4620.3575, subpart 4. Following compliance with part 4620.3575, subpart 4, clearance air sampling must be repeated according to this subpart.
Clearance air sampling must be conducted in the containment area after the containment has been cleaned thoroughly, dried completely, and passed the visual inspection required under part 4620.3575, subpart 4.
The decontamination unit must remain in place and remain operational.
Negative pressure within the containment must be maintained until analysis of clearance air samples is complete.
The clearance air sampling sites must be selected on a random basis within the containment to provide unbiased and representative sampling of the air within the containment.
Clearance air sampling must be performed with equipment that has been cleaned and decontaminated before use.
Clearance air sampling must be conducted as specified in subitems (1) to (3).
Except for clearance air sampling specified in part 4620.3581, subpart 6, item G, subitem (2), before clearance air sampling, all surfaces must be blown with the air from a one horsepower leaf blower to agitate the air and reentrain loose fibers in the air within the containment.
Except for clearance air sampling specified in part 4620.3581, subpart 6, item G, subitem (2), stationary fans must be placed in locations that do not interfere with air monitoring equipment. Fan air must be directed toward the ceiling. One fan must be used for each 10,000 cubic feet of containment area.
When electrical power is provided, the power supply equipment must be underwriter laboratory approved and not modified. Wiring must be grounded and the circuits protected by ground fault interrupt devices.
Equipment such as fans and pumps must be wet wiped with clean water and disposable wipes before removal from the containment.
June 3, 2013
Copyright © 2013 by the Revisor of Statutes, State of Minnesota. All rights reserved.