Abatement Work Practices and Containment
Containment basics
The goal is to keep fibers inside a controlled area and keep building occupants out. Typical controls include critical barriers over openings and HVAC, sealed floors, negative-pressure enclosure with HEPA air scrubbers, warning signs, and a decontamination unit. Maintain negative pressure (commonly about 0.02 in. w.g.) and verify it frequently.
Removal methods
- Wet methods and amended water suppress dust; do not let material dry out.
- Glove bags are for small, localized pipe work; they must be sealed, negatively pressurized if required, and used with wetting.
- Full containment is required for larger or more disturbed areas, sprayed-on material, and work that cannot be isolated.
- Use HEPA vacuums; no dry sweeping or compressed air.
Worked example
A crew must remove insulation from a 6-inch elbow above a suspended ceiling in an occupied office. The elbow is small and accessible, so a glove bag may be appropriate if the bag seals around the pipe, material is wetted, and the ceiling area is isolated. If the insulation is extensive or friable and falls outside the bag, switch to a negative-pressure enclosure.
Traps
Do not shut down HVAC without sealing openings, do not rely on plastic sheeting alone without negative pressure, and do not use a glove bag for a large, crumbling surface. Do not let workers eat or smoke in the work area.