Investigative Procedures for Mould Contamination of Indoor Air

The Durham District School Board in Ontario has recognized mould as a possible causative agent for poor indoor air quality. The Board believes that staff should not teach, nor children learn, in a mouldy environment. A multi-stage procedure is followed to investigate school indoor environments for possible mould contamination. The following investigative procedure is used by the Durham District School Board to verify and address mould contamination of indoor air.

The procedure is based on the underlying principle that mould can become a problem only when certain conditions are met. In order for mould to be a problem in the context of indoor environmental quality, four conditions must exist:

(a)  There must be a reservoir or suitable environment (e.g. carpet, acoustic liner, etc.)
(b)  There must be a source of nourishment (e.g. organic debris, cellulose, etc.)
(c)  There must be amplicication or growth of this mould (through persistent or repetitive addition of water)
(d)  There must be dissemination or a pathway for the mould to enter the indoor air (e.g. air duct, hole in wall cavity, etc.)

Durham's phased approach is based on recommendations by organizations such as Health Canada, The American Industrial Hygiene Association (AIHA) and the American Conference of Governmental Industrial Hygienists (ACGIH).

Phase I - EIQ Profile:
An estimate of the prevalence and severity of health problems and building history are conducted by the School Principal, following specific procedures (see primary reference below) and utilizing IEQ Request for Investigation and IEQ Optional Occupant Interview forms. If the IEQ Profile is being completed on a portable building the Principal shall ensure that the Ventilation Guide for Portables (App. 7 of the principal reference) is posted and complied with.

Phase II - Detailed Physical Inspection
This phase is conducted by the Occupational Health and Safety Department. Inspection concentrates on areas where moisture and substrates may encourage mould growth, such as wet carpet, condensate trays, fan walls in portable buildings, etc. Portable buildings are inspected in accordance with the Detailed Physical Inspection Form (App. 2 of the primary reference below).

Phase III - Sampling
Health Canada, the AIHA and the ACGIH all recognize the strategic utilization of air sampling as useful in the assessment of indoor fungal amplifiers. Other techniques such as bulk sampling and tape peels can also be useful. Sampling is conducted at the discretion of the Occupational Health and Safety Department (e.g. after receipt of a note from a physician following medical assessment of a child with symptoms consistent with an allergic response).

Phase IV - Destructive Testing
Destructive testing occurs when certain structures of a building have to be removed in an attempt to locate the suspected mould amplifier. The trigger for this phase is usually an observation in Phase II of the possible presence of mould or conditions that may encourage its growth, and/or air sampling results indicative on an indoor mould amplifier.

Phase V - Remediation
This phase can involve removal of contaminated materila, decontamination of structures or systems (e.g HVAC) and repair or replacement of materials and/or structures. Remedial work procedures will vary with the location, extent, type of mould growth, etc. As many situations are unique, remedial measures will be determined by the Facilities Services Department and the Occupational Health and Safety Department.

  Record #127, revised 2/14/2001


Related Topics (click for further information)

1. Functions of an IAQ Coordinator
2. Sources of Indoor Pollution in Schools
3. NIOSH Indoor Environmental Quality Investigation


Related Case Studies

1. Durham District School Board Indoor Environment Procedures
2. ALA Indoor Air Quality Program for Oklahoma Schools
3. Fungal Contamination Closes U.S. Elementary School
4. Waterloo District School Board Plant Operations

Primary Sources

1. Guide to Recognition and Management of Indoor Microbiological Agents


Related Resources

1. Indoor Fungi Resources
2. Managing Water Infiltration into Buildings
3. Detecting Moisture Damage and Remediating Biocontamination in Buildings
4. Developing Indoor Air Policies
5. Diagnosing IAQ Problems (section 11)
6. Fungal Contamination in an Elementary School in Southeastern Pennsylvania (Case Study)
7. How Asthma-Friendly Is Your School?
8. Moulds: Isolation, Cultivation, Identification

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