Testing Revisited
In March 1998, I wrote in this column about testing of buildings for mold and other contamination. I had recently returned from attending a forum on indoor environmental testing at the ASHRAE meeting in San Francisco and reported that opinions shared by experts in the field during that forum included:
- There are few if any solid guidelines as to what level of microbial growth is a problem so it is difficult to interpret test results.
- A "clean" report may cause an owner to not continue the search for a problem and lead to continued exposure of occupants to contamination.
- False readings can be given if samples are not gathered correctly.
- It is difficult to analyze the data even from those tests that are conducted correctly.
- A sample gathered in one part of the building or at one particular time of day could be suspect by itself. Only numerous samples gathered at various times of the day and on different days provide meaningful data.
- Correct sampling is very expensive. Generally, the money is better spent on prevention or remediation.
- Test results could be used by the other side in a lawsuit yet are unlikely to help in defense of an IAQ related matter.
Generally, the attendees concluded that if mold or other growth is visible, it should be removed and steps taken to prevent its re-growth. They observed that testing is of little value yet quite expensive if done correctly and concluded that money is better spent on proper maintenance.
What Has Changed?
I pointed out at that time that, in spite of the above opinions, a lot of testing was being done. Today, nearly 5 years later, testing is even more widespread. Environmental Laboratories are growing in both number and size and everyone seems to be collecting samples and sending them in. Yet, if you assembled a like group of experts, their opinions would differ little from what they stated in 1998.
Why is it then that all of this testing is going on if it is of so little value? There are several good reasons for the continued growth in testing even though it can not reliably provide much useful information:
- Legal - Many cases of indoor environmental contamination are ending up in litigation. Experts who are likely to be called on to testify in one of these cases want more to use than their opinions and visual observations. A laboratory report can add credibility to their testimony.
- Regulatory - Several laws have been passed that eventually will require government agencies to establish "safe" levels of mold in indoor environments. Regulators are applying pressure on the "experts" in the field to come up with reliable measurement techniques so there is a lot of experimental testing going on to refine techniques and develop improved procedures.
- Practical - Building owners are hiring remediation companies to remove mold and other contamination. This type of work can be incredibly expensive. The owners want assurance at the end of the job that all contamination has been removed and the facility is safe to occupy and/or live in. They hire consultants to supervise the work and these consultants use sampling as part of their criteria for "clearing" a building or certifying that it has been properly remediated.
Is Testing Reliable?
Since all of this testing is going on, does this mean that we have achieved some breakthrough in the past five years that has made testing much more reliable and the results more accurate. The answer is debatable but most authorities in the field admit that what ever changes have taken place have been modest and there has not been a revolutionary improvement in the science of indoor environmental testing.
What has happened is that there are a lot more individuals who have been trained in indoor environmental science. What experts in the field have stated all along is that testing can provide useful additional information for a trained and knowledgeable individual. Now we have many more individuals who understand the meaning and limitations of the data contained on laboratory reports so they are in a place to realize some value from them. Unfortunately, there are also a lot of individuals who do not understand the information who are also doing testing and this is becoming a real problem.
Should HVAC Contractors Do Testing?
Generally, the answer to that question is, NO! The exception is for those individuals who have decided to specialize in indoor environmental and air quality and have received the extensive training that is required to successfully collect and transport environmental samples to a laboratory for processing and then understand the highly technical report content provided by the laboratory.
There are a lot of individuals doing testing and providing "IAQ" reports who are not qualified and do not understand what they are reporting. I recently witnessed a case where a home inspector was checking a very expensive apartment home prior to closing on a sale. This inspector took one air sample outdoors and one inside of the apartment (normally, at least two samples are recommended outside and many more indoors). The report stated that indoor mold levels were "elevated" when the indoor spore count was about 700 and the outdoor count over 900 (most experts believe the indoor count must be at least 10 times higher than the average indoors to cause concern and this one was actually lower), and there was a health risk because one spore of a toxic mold was found (the one spore could have been brought in on the clothing of the investigator). Based on this report, the prospective buyer became concerned and attempted to back out of the purchase contract. A competent investigator was brought in and could find no indication of mold levels that would indicate a problem in the building.
Are Individual Organisms Important?
When we go to the doctor with a sore throat, a sample will generally be taken and sent off to a laboratory to find out what kind of organism is present. If we get a massive infection, the doctor will normally do a culture of the bacteria causing the infection. These tests are done because antibiotics are manufactured that are highly specific for a certain organism. That way the germ that is causing the disease or condition can be targeted without exposing the body to drugs that might kill the beneficial organisms that live on the skin and in the digestive tract.
There is no parallel in the building environment. Antimicrobial products that are manufactured for the control of organisms in building environments and HVAC systems are designed to be "broad spectrum". That is, they are meant to prevent the growth of or kill the widest variety of organisms possible without being overly toxic to humans and animals. This is because there are no beneficial organisms in building environments. Even those that are normally thought of as friendly like those that help create compost out of dead plant matter can cause damage to building structures and furnishings and give off gasses that are irritating and potentially harmful. Therefore, we want to control all growth not just selected organisms. As manufacturers, we assure effectiveness of our products by testing against some of the organisms that are thought of as being resistant. If we are successful in controlling those, we assume that our products will control all organisms. There are tens of thousands of different organisms. It would be neither possible nor affordable to test all.
What Do We Do?
The old saying that prevention is the best medicine clearly holds true here. The best way to avoid problems with microbial growth is to concentrate on a well-planned and carried out preventative maintenance program. Control moisture and repair leaks at once. Keep the facility and especially the HVAC system clean. Properly utilize microbial control products where growth is likely such as in air handlers and air ducts. Routinely inspect and immediately remove any growth observed with products designed for that use and used according to manufacturer directions.
Dated: January 27, 2003
Mr. Baker's field of expertise is the control of contamination in air-conditioning and ventilating systems by mold, mildew and bacteria. He writes and speaks frequently about the efficacy, legal risks, and regulatory issues involved in various control strategies. He serves on ASHRAE Technical Committee TC 2.3, TC 2.4, TC 9.8, and Sampling of Airborne Particulate Concentration in Commercial and Residential Buildings GPC 17P. He also serves as a member of ASTM D22.06 (Indoor Air Quality) and is on the Board of Directors of the Indoor Air Quality Association and the Florida Public Health Foundation. Because HVAC applications encompass new uses from an U.S. EPA regulatory standpoint, Mr. Baker works closely with the EPA and industry groups, including serving as the chair of the IAQ committee of the Consumer Specialty Products Association, to help formulate policy in this area.
Bob Baker is Chairman and CEO of BBJ Environmental Solutions, Inc., a company specializing in providing clean air through environmentally responsible products, such as BBJ MicroBiocide , BBJ Micro Coil Clean , "FreshDuct Odor Eliminator ", and BBJ Mold and Mildew Remover™ as well as the revolutionary new Power Coil Clean™. For additional information, Mr. Baker can be reached at (800) 889-2251 or through the company web site at http://www.bbjenviro.com.
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