11th International Occupational Hygiene Association (IOHA) International Scientific Conference
Washington, DC, USA
Anne O’DONNELL
HSST Conseils Inc.,
Montreal, Quebec Canada
Keywords: North American guidelines, Mould inspection, Hidden mould, Mould detection canine.
Summary
North American guidelines involving mould detection address the requirement to detect hidden mould found within wall cavities and underneath floor surfaces. The purpose of this work is to present the results of mould detection with the assistance of the mould detection canines following various inspections held by mould inspection experts using conventional inspection tools, not involving the mould detection canine.
Three examples are provided with regards to mould detection successfully achieved using the canine as a tool, versus results based on the inspections held by consultants specialized as experts in mould detection using conventional tools. The examples involve a school where health symptoms resembling mould overexposure were reported for more than 10 years, with ongoing unsuccessful inspections. Another example involves quality control inspections following mould remediation held in a hospital, the other example involves a health clinic where the presence of mould was detected with air sampling, and unsuccessfully located.
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.
We have been using the mould detection canine for more than 9 years as a detection tool for more than 1000 mould inspection surveys held in Quebec, Canada. We have noticed that the canine was successful in identifying locations where mould was within wall cavities that have been missed by other consultants specialized in mould detection.
The practical use of the canines for mould detection is to enable intrusive inspections within wall cavities and under floors, as per North American Guideline requirements. The strength in using the canine is to be able to locate dried mould or within the wall structure, where humidity meters and thermal cameras were not able to provide a positive response for dampness. The purpose of using the mould detection canine is to provide targets for wall openings, minimize wall openings during the exploration, and to help locate building anomalies not linked to known sources of water such as cracks in the foundation, slow plumbing leaks, roof leaks and condensation.
Within this presentation, we will present 3 scenarios, such as :
- Mould detection in a school where mould investigations were held for approximately 10 years and were unable to pinpoint the presence of mould.
- Mould detection in a Hospital, during quality control inspections, following expensive mould remediation.
- Mould detection in a Health clinic, where air testing demonstrated mould contamination unable to be located using conventional mould inspection methods.
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. These dogs have received training in collaboration with the Florida Canine Academy renowned for the training of mould, termite, arson and bomb detection dogs. The mould detection canines consist of specially selected dogs having received more than 1000 hours of training. 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 characterisation of mould is not certain.
The preferred type of dog is the hunting dog; we prefer the Weimaraner breed obtained from a reputable breeder. These dogs are alert, courageous, have stamina and are eager to work and strive to please their masters. Please refer to the figure 1 below for a photo of the mould detection canine at work.
In specific locations of canine mould detection, surface humidity measurements are carried out with the surface humidity meter, simultaneously. The locations are mapped out on an architectural drawing, and usually indicted through a colour code demonstrating the intensity of contamination and remediation instruction. For example, red could require 120 cm of wall panelling removal from the floor, blue could indicate 60 cm removal from the floor and purple color would demonstrate exploration necessary in order to verify further contamination. A special color is used to demonstrate dampness. Please refer to the figure 2 below indicating an example of an architectural sketch depicting inspection results.
The laboratory we use participates in the quality control program administered by the American Industrial Hygiene Association, EMPAT.
Mould remediation recommendations are based on the Canadian Construction Industry Standards or the New York City protocol. These methods are based on surface area covered by visible mould.
Results and Discussion
Presented below are three cases where the mould detection canine was successful in detecting mould where other conventional means for revealing the presence of mould failed. 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
Since 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.
The use of the canine is a tool in which facilitates intrusive mould inspections which is necessary as per the North American Standards. The search for hidden mould is often overlooked by consultants, since tools used for the detection of hidden mould involves dampness and previously wet surfaces that have become dried on construction material due to dry seasonal conditions. In addition, condensation is not readily visible behind wall panels, plumbing leaks can involve slow leaks and are difficult to locate. Also, cracks in the foundation are usually hidden by wall panels. In addition, window leaks may allow water intrusion which is not visible nor wet enough to detect with surface meters. As mentioned by all of the standards, air sampling for mould is not reliable and cannot pinpoint hidden mould contamination.
Our findings involving the canine can result in the detection of nonsignificant mould, hence not requiring mould remediation. During the past decade, through thousands of wall openings resulting from the use of the canine, we noticed canine alerts to appear at specific locations containing relatively higher levels of mould.
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.
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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.
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