The Truth About Chemical Biocides and Sealants in Air Duct Cleaning
When considering air duct cleaning services, you may encounter providers recommending the application of chemical biocides to eliminate bacteria, fungi, and other biological contaminants. Some may even propose the use of ozone treatments. However, the use of biocides and ozone in air ducts remains a controversial topic due to concerns about effectiveness and potential health risks.
Potential Issues with Biocide and Ozone Application in Air Ducts
- Lack of Research: Studies on the effectiveness of biocides and ozone in duct systems are limited. Spraying these chemicals may cause them to circulate throughout your home, potentially exposing occupants to harmful substances.
- Health Concerns: Some individuals may experience adverse reactions to biocides or ozone, leading to respiratory irritation and other health issues.
- Regulatory Considerations: The EPA strictly regulates chemical biocides under federal pesticide laws. Only a small number of products are registered for use inside bare sheet metal air ducts. Using unapproved products or applying them incorrectly can violate federal law.
- Compatibility Issues: Biocides are not approved for use in fiber glass duct board or fiber glass-lined ducts. Using them on these materials could lead to unintended consequences, such as mold growth due to added moisture.
What to Consider Before Allowing Biocide Application
If a service provider suggests using a biocide in your duct system, they should:
- Provide Evidence of Contamination – The presence of microbial growth should be confirmed by an expert, not simply assumed based on a petri dish test.
- Explain Why Physical Cleaning Is Insufficient – A professional should justify why brushing and moisture control alone cannot eliminate the issue.
- Show the Biocide Label – The label should list approved uses and safety information.
- Apply Biocides Only to Uninsulated Duct Areas – To minimize risks, biocides should only be applied after proper cleaning.
- Follow Label Instructions Strictly – Proper application techniques are crucial to preventing unintended exposure.
Are Sealants Effective in Preventing Dust and Dirt Release?
Some manufacturers market sealants as a solution to prevent dust and dirt from being released into indoor air. However, similar to biocides, sealants have their own set of concerns:
- Incomplete Coverage: Laboratory tests indicate that sprayed sealants do not always completely coat duct surfaces.
- Potential Safety Risks: Sealants may alter the acoustical properties or fire resistance of duct materials and could even void manufacturer warranties.
- Unknown Long-Term Effects: There is limited research on the toxicity of sealants and their potential deterioration over time.
Current Industry Recommendations
Leading organizations, including the EPA, NADCA, NAIMA, and SMACNA, do not recommend the routine use of sealants for encapsulating contaminants in ducts. However, sealants may be appropriate in cases such as:
- Repairing damaged fiber glass insulation.
- Addressing fire damage within ductwork.
Sealants should never be used on wet duct liners, to cover active mold growth, or to mask debris without proper cleaning.
Trust Armstrong Duct & Vent for Safe, Effective Air Duct Cleaning
At Armstrong Duct & Vent, we prioritize the safety and well-being of our customers. We use industry-approved cleaning methods to remove contaminants without unnecessary chemical applications. If you’re considering air duct cleaning and want a professional, honest assessment, contact us today at 603-627-7016 or visit our contact page.
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