Originally Posted By: Caoimh?n P. Connell
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Hello Mr. Andersen:
Thanks for your comments.
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The mold in the first picture is not on sheetrock, it is metal.
Mould doesn?t grow on metal. For the purposes of this topic, mould is a saprophytic organism that grows on (primarily) cellulose. The mould in the photograph is growing on the same stuff as found in drywall (cellulose). In some cases, it may appear that mould is growing on metal, however, closer inspection will reveal that the mould is actually growing on something that is settled or attached to the metal.
In any event, the point of the drywall discussion was to demonstrate that the use of fungicide is not warranted.
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We are talking about one HVAC unit, in one part of the country (assumably where the HI is from). It is true in every part of the country, but is more of an issue in some than others. Are you saying the "Swamp Coolers" in AZ have no problem because it's hot and dry there? Why are they called Swamp Coolers?
Mould is mould is mould and it doesn?t matter where in the country one finds it ? what changes are the environmental conditions effecting the grown. In parts of the country where relative humidities are elevated, dew points are necessarily elevated as well ? as such small temperature drops in the HVAC may result in condensation problems resulting in mould growth on the cellulosic material in (or on) the ducts ? whereas the same HVAC system in a drier clime may not have similar condensation problems at twice the temperature drop.
Swamp coolers whose trickle media are cellulosic will exhibit a greater mould potential than swamp coolers whose trickle media are metal mesh ? the meteorological conditions not withstanding. The effectiveness of a swamp coolers is what changes as the air becomes drier ? not its potential for fungal invasion.
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The system design of HVAC equipment promotes an artificial environment that is closer to what FUNGUS like than the ambient air (no matter where you live).
Not quite true. HVAC systems do not necessarily contain what all fungi need ? a food source. In the case of moulds, that food source is almost exclusively cellulose. Therefore, unless there is sufficient food in sufficient quantities then the moisture content is simply unimportant. Furthermore, the moisture content must be within tolerances on the available food source, or again ? no growth. To that extent, the system design of HVAC equipment does NOT promote an artificial environment that is closer to what FUNGUS like than the ambient air (no matter where you live). Furtheremore, ambient air concentrations of moulds can be orders of magnitude greater outdoors than indoors - even for spaces with visible mould growth.
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The picture is an indication of a "lack of maintenance", not improper equipment design or an environmental issue requiring mold testing.
100% agreement.
You comments on CO vs. mould is well stated. The reality is that there is virtually no science behind the so-called killer moulds and there is absolutely no such thing as ?toxic mould.? Having said that, it is important to note that unlike CO, mould destroys that upon which it grows (that is its function). As the mould is growing on the cellulose of the duct wrapping it is damaging the wrapping and degrading the product.
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I also spent many years killing off mold on HVAC equipment and correcting Indoor Air Quality and never once created an indoor air quality problem from the chemicals used.
To your knowledge. The reality is that the chemical exposures posed by the biocides may have had deleterious effects that were not noted or associated with their use.
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Are you telling me that all the water treatment products we use in annual maintenance and operational maintenance on HVAC equipment is not required?
No. As I stated:
Although some HVAC systems do require the use of biocides in a controlled fashion as part of routine maintenance, in a recent study concerning the efficacy of disinfectants, the authors used a variety of disinfectants and follow-up treatments on drywall that had been colonized with a variety of moulds. The point being that such chemicals are not a panacea and the focus of attention should be on proper maintenance ? in some cases, but not all cases, that proper maintenance may include appropriate use of biostats.
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If these chemical treatments were not used we would all have "Legionnaires Disease".
Not true. The organism that causes Legionnaires Disease (
Legionella pneumophila) is a ubiquitous Gram- negative organism that resides in many treated and untreated HVAC water systems. As a general rule, I caution maintenance people to NOT sample for the organism since they will probably find it (chemical treatments notwithstanding) and then they will have a scare on their hands that they will have difficulty in abating.
Legionella pneumophila, like moulds, is very prevalent. The epidemiology of the disease is not exclusively incumbent on mere exposure- furthermore, the environment of the HVAC system wherein it resides needs some unusual characteristics to produce the correct strain. Exposure does not equal disease.
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However, again sheetrock is not used in HVAC System design.
Not true. Sheetrock and (more importantly) the constituent of sheet rock that supports mould growth is used in HVACs. I very, very often find sheetrock return plena and false ceiling return plena as part of an HVAC design.
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I assume you are connected in some way with the Mold business.
I am just a scientist - a forensic industrial hygienist. My role is to assess and study human exposures to ______ (mould, chemicals, ionizing radiation, lasers, sound, Bacteria, etc?.) and to present tenable findings in court. I was one of the first industrial hygienists to buck the silliness of the original CDC report on Stachybotrys atra as being very poor science. (And initially, I took a LOT of heat for it!) You can read my review of the CDC reports at:
http://members.aol.com/piobin/sok.html I am often called to perform residential mould inspections or perform mould exposure assessments (or as a rebuttal expert in cases where an HI has taken an expert position on moulds and Bacteria that cannot be supported by science).
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There is a place for your services. But, not every spec of mold encountered needs to be attacked with hellfire missiles.
My point exactly, so why are you so keen to keep using such chemical missiles? The truth is that the mould in question could be adequately remediated and controlled by using your Mom?s tried and true ointment ? elbow grease (no bleach, biocides, etc? - maybe a little Lysol if you want to get fancy), and then alter the conditions which created the moisture problem in the first place.
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If mold is in sheetrock where I inspect, I call it out as a MAJOR REPAIR and SAFETY ISSUE and inform the client that all the effected building materials will have to be torn out,...
That should keep you busy!
ALL the sheetrock in
EVERY house you enter will have to be torn out since mould, and particularly
Stachybotrys atra, the killer black mould of newspaper hype, is found in
EVERY sheet of drywall in
EVERY house in the nation. You will be a very busy man, and likely to receive a recognizable Christmas gift from the drywall industry.
In truth, not only is mould present in every piece of drywall, but very often remediation of even thousands of square feet of vegetative growth can be quickly and inexpensively effected without having to remove the drywall by simply wiping the vegetative growth from the wall. Only when the water damage has degraded the structural integrity of the drywall or colonization has degraded the structural integrity of the drywall is removal warranted.
Fell free to pursue the matter further.
Cheers,
Caoimh?n P. Connell
(The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.)
AMDG