The M Word – Mould in Fan Coil Units
By Jeff Jeffcoatt, P.Eng., BDS, RCM Vice President, Condominium/Strata Group
A Four Letter Word
Some property managers treat the discovery of mould in their buildings as being akin to using a four letter word (and I guess that is true of you Americanize the spelling to mold) but the fact is it does exist and it needs to be addressed. At a luncheon meeting held by ACMO in December 2015, McIntosh Perry was a member of the panel that presented a “white paper” from the University of Toronto encouraging a more open and practical approach to mould identification and remediation, particularly as it occurs in all Fan Coil Units over time. Since mould occurs naturally in the air we breathe outside, and is actually a useful contributor to breaking down soils, leaves, etc., there should be no surprise that it will exist in the indoor air as well. The problem is that the Fan Coil Units in highrise buildings can become a breeding ground for colonies of mould, and present some residents with breathing difficulties. The health effects of exposure to airborne mould are reviewed in many documents, including Health Canada’s residential Indoor Air Quality Guideline for Mould, and the national Collaborating Centre for Environmental Health (NCCEH). The “white paper” also discusses the various types of mould commonly found in residential fan Coil units, and the effects they may have, particularly with residents who may be more sensitive to airborne spores, such as those with a pre-existing condition like Asthma. It is recommended reading for all Property Managers!
The insulation that lines the inside of the Fan Coil Unit (FCU) cabinets can, over time, become a breeding ground for different types of mould “colonies” as the “ideal” conditions of high humidity, no light, and warmth are all present inside the FCU cabinet. There can be differing degrees of mould growth within each FCU within any given building, depending upon such things as age; preventive maintenance; the level of relative humidity in the suite; the frequency of use of the FCU fan; and the physical location of suites within the building configuration. There are a couple of issues stemming from the original manufacture of the equipment that can definitely make the mould growth more prevalent, and steps should be taken in the Remediation Plan to address these issues to help minimize the reoccurrence of mould growth.
The Fan Coil Unit is simply a coil that has heated or cooled water passing though it (seasonal dependent) and an electric fan that blows air across the coil to provide the required conditioning of the air. In the summer the coil is cooled and the air is humid, and so condensation occurs on the coil which drips down to a containment “drip pan” under the coil. This drip pan is then drained via a small plastic hose down to the main vertical drain stack in the building, and down to the sewer. The problem is that the original flat drip pan allows condensate water to pond in it most of the time, and this water can then be vibrated and splashed onto the insulation lining the inside of the cabinet. Couple this with the deterioration over time of the insulation and we have ideal conditions for mould growth in the summer, made worse in many instances by the old style fibre-glass insulation breaking up to provide a rough surface for the colonies.
What To Do
The first step to be taken would be to undertake an inspection of a sample quantity of Fan Coil Units in different areas of the building to identify the magnitude (or not) of the problem, so that a comprehensive plan can be developed to address any issues found. This step should be done with the assistance of a qualified engineering consultant. McIntosh Perry has an experienced Hazardous Materials/Environmental Health & Safety team that has performed hundreds of fan coil mould unit inspections and remediations.
The plan could include various levels of mould remediation from simple treatment or insulation removal, ranging all the way up to complete FCU replacement or retrofit. Each identified level of mould contamination would require the appropriate containment and disposal methods together with the required level of protection of the person working on the unit. There are guidelines and specifications for all such actions that can be supplied by your engineering consultant.
The condition of the drip pan and fan motor configuration should also be reviewed, and decisions made as to partial replacement, complete FCU retrofit, or installation of a new factory made FCU. Note that the difference between FCU retrofit or new replacement is usually that the retrofit assembly will usually fit directly into the cabinet space of the old FCU, whereas new factory made replacements may require some work in adjustment of the cavity such as dry-wall work.
The bottom line is that the issue of mould in residential Fan Coil Units is a normal occurrence and should be properly addressed as a maintenance issue, rather than discussed in hushed tones and hidden away. Your consulting engineers will have all the details you need to proceed with addressing the problem calmly and efficiently!
To download a copy of the white paper “Fan Coil Contamination of Growing Concern” please click here.
For more information on how to deal with fan coil contamination, please email us or call 1.888.348.8991