The Use Of Antimicrobial Chemicals In Air Duct Systems

Introduction

Currently many customers inquire about the use of antimicrobial chemicals in conjunction with air duct cleaning activities. The reasons for this inquiry are most likely due to advertising exposure for these types of products and media reporting of “catastrophic” contamination cases around the country. Many people suspect that they are at significant personal risk of exposure to unseen “toxic molds” and are willing to take any precautions they can.
As a result of much of the information dispersed through the various media outlets many people perceive that any mold exposure necessarily means risk of personal harm. This is certainly an overstatement of fact. Mold is a natural part of our environment and we are surrounded by it constantly in various degrees. In many contexts mold is beneficial such as in cheese production and in organic composting. What should be of concern is unnatural indoor amplification sites that can cause damage to a building structure and lead to personal exposures to levels of spores and allergens in excess of natural, or ambient, conditions. For individuals who are potentially at risk of poor health due to mold exposure the most important thing to do is consult closely with a physician.
When mold amplification occurs indoors there are two key ingredients present. One is organic-based nutrients and the other is moisture which the organisms need to perform metabolism of the organic nutrients. Certain controls to limit organic nutrients can be implemented such as cleaning. However, there are many components of indoor living that are organic in composition and can’t be removed from the environment, such as substantial portions of the structure itself. Moisture on the other hand can and should be controlled inside structures. Standing water or constant dampness due to water leaks can facilitate mold amplification. In addition, excessive indoor relative humidity can be enough to cause problems. Sources of excessive moisture in indoor environments should be identified and eliminated, or controlled if elimination is not possible, to reduce the potential for mold amplification.
With specific regard to air duct systems, prevention of mold amplification is best achieved by eliminating organic nutrients (by cleaning) and controlling moisture (by routine maintenance). If a mold amplification occurs inside an air duct system it will be because there are nutrients and moisture present that should not be there. Whether or not chemical treatments are employed the underlying causes (nutrients and moisture) still need to be corrected or the occurrence is likely to return.
The USEPA has jurisdiction over the use of chemical products used to reduce mold organisms present in duct systems. These products are relatively mild in nature and have no ongoing affect beyond application time. The reasons for these limitations are deliberate since it is deemed risky to put potent chemicals inside a system designed to distribute the air people breathe through a building. Under no circumstances should anyone believe that the application of such chemicals to an air duct system can transform that system into an air purifying device. A forced air system used for temperature control in a building does not have the potential designed into it for it to be used as an air purifying system and the USEPA has stated that air purifying claims are a violation of their regulations.
To further complicate the matter of using antimicrobial pesticides in air duct systems there are the legal considerations. Both Massachusetts and New Hampshire require all for hire pesticide applicators to be licensed. Recently, Armstrong received a letter from the Massachusetts Department of Agriculture warning that Air Duct Cleaning contractors did in fact need to be licensed in their jurisdiction and that they would investigate and prosecute violations. One of the key issues in this legal consideration is one of insurance coverage. Most general liability policies that contractors obtain to operate a business have pollution exclusions that would not cover the costs of rectifying an incident involving the application of chemicals. To be properly covered for antimicrobial pesticide applications a specific pollution rider would have to be purchased with the general liability policy.
As a policy Armstrong Heating & Power Vac, Inc. does not apply or recommend applications of antimicrobial chemicals with routine air duct cleaning. The occurrence of microbial proliferation in air duct systems in the Northeast marketplace is relatively rare (compared to the hot and humid climates) and the costs of compliance are too high to incorporate for those rare occasions. Several sources (American Industrial Hygiene Association and the USEPA) have even gone to the length of printing that there is a substantial body of evidence that these products are no more effective than thoroughly washing surfaces with soap and water (which doesn’t carry the legal burdens). For the rare incident where Armstrong comes in contact with an actual mold amplification site inside air ducts it is easier for us to note and report the situation and refer treatment of that spot to qualified and license individuals. Armstrong focuses on thorough Source Removal Air Duct Cleaning as a part of a preventive regimen to reduce the risk of microbial amplification inside buildings.

Sanitizing Limitations and Disadvantages:

  • Adds cost to project (materials and application time, licensing, insurance) with little or no benefit returned.
  • Only effective for the duration of the application (approximately 1 hour).
  • Doesn’t prevent problems from occurring because there is no ongoing effect.
  • If microbial contamination is present chemical applications don’t correct the root problem and root conditions left unchanged will increase the likelihood of recurrence.
  • According to application instructions treatments need to be applied when cleaning procedures are completed.  Most products require the work area to be evacuated of personnel during application time unless they are equipped with proper PPE.  This can interfere with work schedules.

The team was very respectful of my home with their equipment and Devin was knowledgeable and helpful in explaining the process and results. Would highly recommend and will be using them again in the future.

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alternative approach

  • Don’t make general applications where there is no compelling need.
  • When mold proliferation is found, identify the location, identify the offending moisture sources and recommend correction.
  • Make report of actual mold proliferation locations so that a licensed pesticide applicator can treat those spots as necessary.
  • This limits cost and ensures enduring solutions to actual problems.

Give us a call at 603-627-7016 today! We look forward to hearing from you.