Abatement work practices and engineering controls
What this domain tests
The field mechanics - wet methods, HEPA filtration, negative pressure - and the prohibited shortcuts that create visible emissions.
Core work practices
- Wet material with amended water (water plus surfactant) before and during disturbance, and keep it wet through bagging. Wetting suppresses fiber release but does not eliminate it.
- Remove components in whole pieces where feasible, lower them in leak-tight wrapping, and never drop or throw debris. Seal the ends of pipe insulation sections before removal.
- HEPA vacuum surfaces and debris. No dry sweeping or shoveling, no compressed air, and no high-speed cutting, grinding, or sanding unless the tool has HEPA local exhaust.
- Glove bags allow pipe removal without a full containment; mini-enclosures serve small isolated jobs.
- Negative-pressure containment with HEPA air machines holds the work area at roughly 0.02 in. w.g. (about 5 Pa) below adjacent spaces so leakage moves inward. Log manometer readings.
- Provide adequate air changes, commonly 4 per hour, and discharge filtered exhaust away from air intakes.
- Critical barriers seal HVAC, doors, windows, and penetrations before poly goes up.
Worked example
Crews must remove 40 linear feet of TSI from a horizontal main above a drop ceiling. Plan: build containment or use glove bags, shut and seal HVAC, wet with amended water, wrap each section in 6-mil poly and tape the ends, cut into short sections, lower by hand into bags, HEPA vacuum the substrate, then remove the poly as a unit. Dropping sections into a dumpster would create visible emissions and fail NESHAP.
Traps
- Assuming amended water replaces containment.
- Shutting off the negative air machine while workers are still inside.
- Using a high-pressure sprayer that fractures friable material.