Level 3 Protocols – Remediation of Large-Scale Mould Growth (Areas greater than 10 m²)

Level III mould abatement includes all Level II measures, as well as the following:

  1. A health and safety professional (HSP) experienced in performing microbial investigations must be consulted prior to commencing remediation. The HSP must determine whether the following procedures are applicable to the specific remediation project, and identify any required changes. In addition, the HSP will provide periodic hands-on monitoring of all associated mould removal activities.
  2. Workers shall wear a full-facepiece air purifying respirator fitted with P100 filters, or preferably, a tight-fitting positive-pressure full-facepiece Powered Air Purifying Respirator with high-efficiency particulate filters.
  3. Workers shall wear impermeable gloves and full-body dust-impervious coveralls, with attached hoods, tightly secured with tape at the ankles and wrists.
  4. Workers shall wear disposable boot covers or separate work boots that can be effectively cleaned with a HEPA vacuum or wiped clean prior to removal from the work area.
  5. Isolate the work area from adjacent spaces using temporary hoarding, tape, and polyethylene sheeting, etc. Cover all walls that form part of the enclosure perimeter with one layer of polyethylene sheeting, taped in place. Where temporary walls form part of the enclosure perimeter, provide two separately sealed layers of polyethylene sheeting, one on each side of the temporary wall.
  6. Provide a negative pressure within the enclosure, by using portable, HEPA-filtered exhaust fans (negative air machines). Provide a minimum negative pressure of 5 Pascals (0.02 inches of water column) and a minimum of four air changes per hour. Where possible, discharge the filtered air outside the building and away from people.
  7. A competent person must regularly inspect the work area and record, in writing, any defects in the enclosure, barriers, and change room, at the beginning of every shift, at the end of every shift where no shift immediately follows, and at least once daily on days where there are no shifts. These inspections should be documented in writing.
  8. Provide a Worker Decontamination Facility, to include a Clean Change Room and a Dirty Change Room. .Install flap doors at each opening into and within the Decontamination Facility. Provide a wash station consisting of, at a minimum, a basin, fresh water, soap, and toweling in the Clean Change Room. Consider providing a shower for worker comfort. Construct and arrange the worker decontamination rooms in such a way that everyone entering or leaving the work area must pass through each room of the decontamination unit.
  9. Before entering the contaminated work area, workers must first put on clean coveralls and a respirator in the Clean Change Room. When exiting, workers must use a HEPA vacuum in the work area to remove gross contamination from coveralls and boot covers (or separate work boots). Workers must then enter the Dirty Change Room and remove dirty coveralls and boot covers, the latter are to be used and then disposed of. Work boots used without boot covers must be removed and stored in the dirty change room. On leaving the work area, workers must then clean their face and hands in the wash station.
  10. A separate Waste Decontamination Facility, consisting of a Double Bagging Room and a Waste Transfer Room, should be provided where large volumes of waste will be removed. Seal the waste into bags in the contaminated work area, and wipe the exterior of the bags or other suitable sealed containers. Transfer the bags to the Double
  11. Bagging Room and place in a second bag or sealed container. Transfer the double-bagged waste or container into the Waste Transfer Room for removal by workers entering from outside the decontamination facilities.
  12. Upon completion of removal and cleaning, the Health and Safety Professional shall inspect the Level 3 work area for acceptable completion, through a combination of careful visual inspection, and possibly, testing. A site will be considered acceptable and clean when a thorough visual inspection shows that all the removal work has been completed and that all surfaces in the work area are free of any dust or debris. In addition, mould measurements (air samples, swabs, tape-lifts, or vacuumed dust samples) can be taken to demonstrate that the work area is no longer impacted by the mould contamination and removal process.
  13. Generally, air samples are collected from the work area and compared to samples taken in reference areas (areas adjacent to where the work area make-up air is being drawn, or outdoor locations). An acceptable condition is indicated when concentrations of airborne fungal particles in the work area are not significantly elevated when compared to concentrations in the reference samples, and the types of fungal particulate present in the work area do not differ significantly from those present in the reference samples. The samples may so be compared to any similar measurements taken in the work area prior to the remediation work. Again, the sample should be examined by a qualified mould professional.

Level l Protocols – Remediation of Small-Scale or Minimal Mould Growth (Less than 1 m²)
Level ll Protocols – Remediation of Medium or Moderate Scale Mould Growth (Areas between 1 m²– 10 m²)