The mould detection canine, an essential tool in the compliance of North American Guidelines with regards to mould detection.
Anne O’DONNELL, HSST Conseils Inc.,
Montreal, Quebec Canada
Introduction
North American Standards involving the inspection for mould require intrusive inspections which includes inspections within wall cavities and under floors. Common Ways of searching for hidden mould involves using surface humidity meters, the infrared camera, boroscopes and opening walls or floor cavities where architectural sources of water are identified or through visible results from water leaks.
Methodology
Mould inspections are visual and comply with the North American Guidelines developed notably by: the American Industrial Hygiene Association (AIHA), Health Canada, Canadian Housing and Mortgage Corporation and the American Conference of Governmental Hygienists.
The canines used are highly trained dogs. Areas of alert require surface openings and visual inspection. The presence of mould maybe insignificant or important, which may require mould remediation. Some examples of building construction materials demonstrating visual mould can be sent out for laboratory analysis where legal documentation is necessary or in the case that visual characterization of mould is not certain.
Results
Three cases where the mould detection canine detected mould where conventional methods failed.
School
Mould detected by a canine where air testing failed for 10 years.
The three cases presented involve an Elementary school, a quality control inspection following the mould decontamination in a hospital and an inspection for mould following the construction of a new health clinic, not yet delivered nor occupied.
Elementary School
For more than 10 years, students and teachers in a school were complaining of health issues which included asthma and other symptoms resembling overexposure to mould.
Three studies involving air sampling within the school, demonstrated results indicating normal fungal flora. However, the occupants were suspicious of likely presence of mould based on their continued symptoms resembling overexposure to fungus. With the use of the canine, fungal contamination was located in the school basement, ground floor and upper floor outside walls. Based on the New York city protocol criteria for mould decontamination, the amount of mould was identified as a level 4, the highest level scaled corresponding to more than 10 square meters of continuous mould. The source of dampness was located under the floating floor, with regards to the leaking plumbing fixture underneath the floor structure. Furthermore, mould was found behind some of the gyprock wall panels through water infiltration through the base of the concrete foundation. Please refer to figure 3 for an illustration.
Hospital
A defect in building construction of the hospital resulted in water infiltration through the outside envelope. Following decontamination work involving thousands of dollars, we received a quality control inspection mandate in order to ensure that mould was thoroughly removed. The location of the mould was identified by mould specialists and by the public health as being only present within 2 meters of the periphery of the building. We commenced our inspection on the first floor in which previously received mould decontamination. Our results demonstrated hidden mould behind wall panels present past the 2 meter periphery, already decontaminated, including other locations. Please refer to figure 4 for an example of mould uncovered within wall structure not discovered by the previously hired mould expert.
New Health Clinic
A water leak was discovered on the ground floor within the Dentistry Department of a new Health Clinic that had not yet been habited. Dampened construction materials had been removed, including organic material that had been contaminated by mould growth. Following mould remediation activity, the Industrial Hygienist hired by the Quebec Public Health carried out fungal air testing. The air sampling results demonstrated abnormal mould air concentration suggesting fungal contamination.
The mould detection canines were hired to locate the residual mould. Our results demonstrated mould present within gyprock wall panels and underneath floor tiles. Also, we found mould on the outside envelope of the building. Our mould investigation resulted in the removal of the outside wall panels accessible behind the bricks and outside wall coverings. The whole outside building envelope was stripped in order to remove the outer envelope wall panel. Please refer to figure 5.
Conclusions
The use of the well-trained mould detection canine has proven success in locating hidden mould as per the North American Guideline requirements involving instrusive inspections. Case studies are presented involving situations where occupants were complaining of mould symptoms during 10 years, and where mould experts were unable to locate hidden fungus. Also, presented are quality control inspections for a hospital that had undergone mould remediation. The canine detected mould within wall cavities that were not identified by the mould expert that designed the quality control survey. Another example of the canine detecting mould involves air sampling indicating the presence of mould in a new facility. With the assistance of the canines, mould within the outside envelope was discovered which resulted in major mould decontamination involving the complete removal of the building exterior covering.
Conventional instrumentation for the detection of mould involving moisture meters, infrared cameras, boroscopes, building engineering /architectural expertise is limited with regards to intrusive inspections for the detection of hidden mould.
References
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American Industrial Hygiene Association, Assessment, Remediation and Post Remediation Verification of Mold in Buildings. IAQ GOV-659, 2004.
American Industrial Hygiene Association, Recognition, Evaluation and Control of Indoor Molds, Fairfax Virginia, 2008.
American Industrial Hygiene Press, Report of Microbial Growth Task Force, Fairfax Virginia, May 2001.
American Industrial Hygiene Association, Field Guide for the Determination of Biological Contaminants in Environmental Samples, 2nd Édition. 2005.
Canadian Construction Association, Mould Guidelines for the Canadian Construction Industry, 82-2004.
Health Canada, Residential Indoor Air Guideline Quality Guidelines, March 31st 2007. ISBN: 978-0-662-45739-8
La Presse, Daily Newspaper (French), Mould at the Harfang des Neiges School, where air testing has failed, August 12th 2012.
New York City Department of Health, Bureau of Environmental & Occupational Disease Epidemiology, Guidelines on Assessment and Remediation of Fungi in Indoor Environment. 2008.
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