Four Critical Aspects of a Mould Remediation

• Protecting Yourself and the Public
• Assessment
• Establishing an Effective Remediation Environment
• The Remediation Process
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Establish an Effective Remediation Environment

Levels of contamination

Normally this will be determined by findings at the initial site assessment or by the environmental consultant.

There is documentation available regarding Levels of Contamination.

• CCA 82 (Canadian Construction Association web-site)
• IICRC S520 Standard for Professional Mold Remediation

Type of containment

Level One contamination (extent of visible and hidden mould growth is less than 1 square meter “10 square feet”) normally requires source or no containment . Recommend controls in place to prevent the spread of contamination .

Level Two contamination (total affected area between 1 square meter and 10 square meters “10 to 100 square feet”) normally requires a limited containment with impermeable poly barriers and negative air.

Level Three contamination (total affected area is greater than 10 square meters “100 square feet” or the potential for occupant or remediator exposure during remediation is estimated to be significant) requires use of critical barriers, full-scale containment with impermeable poly barriers, negative air, and a two stage decontamination/clean room.

Required equipment

Level One contamination

Minimum: N95 or half facepiece respirator with HEPA filters, gloves, goggles, and HEPA filtered vacuum.

Level Two contamination

Minimum: half facepiece respirator with HEPA filters, gloves, goggles, disposable coveralls, HEPA filtered vacuum, and HEPA filtered air scrubber.

Level Three contamination

Minimum: full facepiece or powered air purifying respirator (PAPR) with HEPA filters, gloves, disposable coveralls (covering head and boots), HEPA filtered vacuum, and HEPA filtered air scrubber.

Note: Higher levels of respiratory protection should be considered for situations where the “extent of visible and hidden mould growth” is categorized as small (level one) or medium (level two). For example, full facepiece powered air purifying respirators (PAPRs) with High Efficiency Particulate Arrestor (HEPA) filters will afford protection to the eyes not available with half facepiece respirators.

Remediation of “Level two” or “Level three” mould contamination should be conducted by trained remediation personnel.

HVAC isolation

At all times the HVAC (heat, venting, air conditioning) system should be isolated from the remediation area. All supply and return air vents within the containment area must be blocked.

It is important to note that, with forced-air furnaces, the establishment of negative air has the potential to create a backdraft situation. This could create elevated levels of carbon monoxide in the indoor environment.

After containment is complete, the protection of personnel, air flow, removal of contaminated materials, and cleaning are the major components of the remediation process.

HEPA (High Efficiency Particulate Arrestance)
A true HEPA filter is 99.97% pure to .3 microns.

A micron is 1 millionth of a meter

Negative Air Equipment

Filter efficiency testing

DOP (Dioctyl Phtlalte) Testing by third party for HEPA filter efficiency.

The establishment of negative air should take into consideration:

the capture zone

availability of make-up air

flow of air through the containment

The Capture Zone

Try to eliminate any areas in the containment where there will be no air movement.

It may be necessary to run a flex hose from the negative air machine that can be moved to the immediate work area. This is an effective way to eliminate dead air pockets where contaminants can accumulate.