Work Practices
What the work-practices domain tests
This domain tests how abatement is physically done: containment, engineering controls, worker protection, waste handling, and clearance. Minnesota expects practices that keep fibers inside the work area and verify that the area is clean before reoccupancy.
Core rules
- Friable abatement generally occurs inside a negative-pressure enclosure. Critical barriers isolate openings, HVAC, and fixed objects; plastic sheeting protects surfaces; HEPA-filtered negative air machines maintain directional airflow into the work area.
- The decontamination unit has a clean room, shower, and equipment room so workers and tools do not track contamination out.
- Use wet methods and careful lowering of material; bag or wrap waste immediately in labeled, leak-tight containers. Dry sweeping, compressed air, and dry shoveling are prohibited because they re-entrain fibers.
- Small operations still need controls: glove bags for accessible pipe insulation and mini-enclosures for small friable jobs, with HEPA vacuuming and wet cleaning.
- Clearance is not just a look-around. After visual inspection, air sampling follows the project clearance protocol; AHERA school projects use a 0.01 fibers per cubic centimeter PCM clearance level. Do not reopen until clearance is achieved.
- Waste goes to an approved landfill under MPCA requirements; manifests and labels must match the waste.
Worked example
A crew removes 40 linear feet of friable pipe insulation in a mechanical room using glove bags. They wet the insulation, seal it in bags, then dry sweep the floor and run a shop vacuum without HEPA filtration. The job is deficient: dry sweeping is prohibited, the shop vacuum can exhaust fibers, and the area needs HEPA vacuuming and wet cleaning before visual inspection and clearance sampling. Glove bags are acceptable only when the bag can be sealed around the pipe and the work area is controlled.
Traps
Negative air machines must be HEPA-filtered and sized for the enclosure; plastic on the floor alone is not containment; a visual pass does not replace air clearance; and nonfriable material can become regulated when cut, ground, or broken.