Rigid fiberglass HVAC duct board air handler (C) Daniel Friedman

Rigid Insulating Board HVAC Ducts
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Q&A on use of rigid insulating board to build air conditioning or heating ducts
Tools used to construct ductwork
How to use fiberglass duct board to construct HVAC ductwork
Use of rigid duct board with a thermosiphoning air collector (TAP)
Using basement air with a thermo-siphoning air collector system
Questions & answers about rigid fiberglass duct insulation board
Solar Age Magazine Articles on Renewable Energy, Energy Savings, Construction Practices

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This article discusses the use of rigid insulating board to construct air conditioning and heating system ductwork, and use of rigid ductwork with a thermosiphoning air collector system (TAP). Accompanying text is reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss. Our page top photograph shows reinforced aluminum foil faced fiberglass duct board used to construct the supply air plenum on a heating system.

Readers should also see DUCT SYSTEMS, and see Recognizing Fiberglass Duct Insulation. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.

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Rigid Insulating Board Air Conditioning & Heating Duct Construction

The link to the original Q&A article in PDF form immediately below is followed by an expanded/updated online version of this article.

Q&A on Rigid Insulating Board Ductwork: Rigid-Insulation Ducts - PDF version, Use your browser's back button to return to this page

The question-and-answer article below paraphrases, quotes-from, updates, and comments an original article from Solar Age Magazine and written by Steven Bliss.

Rigid-Insulation Ducts

Question:

I have heard that rigid insulating board can be used to construct heating ducts (or air conditioning ductwork). Can you provide information about the construction of rigid insulating board ductwork, including duct construction tools, etc.?

Is it reasonable to use rigid duct board with a thermosiphoning air collector (TAP), considering that I desire to move air 12 to 15 feet from the south wall to the middle of a one-story house?

This thermosiphoning air collector plan also includes using air from the basement to enter the cold side of the TAP. -- Byrl Bowman, Kalamazoo, MI

Answer:

The product you refer to is fiberglass duct board, available from Certainteed, Knauf, and Owens Corning.

The fiberglass insulating board panels are one-inch in thickness, R-4.3, rigid-fiberglass panels that have a reinforced kraft paper or foil facing on one side. Rigid fiberglass duct board panels can be cut and fitted on site using a utility knife and special grooving tools to make the folds and laps.

The duct board sections are stapled together and sealed using pressure-sensitive aluminum foil tape.

The duct construction hand tools are made by AmCraft, Inc..

To purchase fiberglass insulation duct board materials, check with the larger heating and air-conditioning supply houses in your area, or with a manufacturer's rep.

As for your plan to use a thermosiphoning air collector, it sounds fine, but don't expect much air flow from a thermosiphoning collector if the system is ducted. A fan will be needed.

Technical Opinion About Rigid Fiberglass Ductwork

Foil faced rigid fiberglass duct board has proven an excellent system for constructing air plenums and main trunk lines for duct systems for both heating and air conditioning, and is in popular use across North America as well as in other countries. -- DJ Friedman

Advantages of Rigid Fiberglass Duct Board

Rapid, easy, low-cost onsite custom fabrication of ductwork
Combination of both duct insulation and a rigid material to form the duct itself
Ductwork constructed of this material transmits much less noise than metal ductwork

Disadvantages of Rigid Fiberglass Duct Board

Exposed fiberglass in ductwork (C) Daniel Friedman

Cleaning difficulty: When ducts are constructed using board that is foil faced only on the outside, the inner, fiberglass insulation can not be mechanically cleaned without damaging the ducts. If the fiberglass is damaged an increased level of release of fiberglass into the building air may be a problem for building occupants. See FIBERGLASS HVAC DUCTS and also Fiberglass Fragment Hazards for details.
Mold growth: In some air conditioning systems (improperly maintained, improper handling of condensate, or location in very humid climates), over-spray of condensate in the air handler or leaks into the ductwork can combine with the collection of organic debris in house dust to support mold growth.

In some instances problem mold growth may be present in duct work at a significant level, although usually our field investigation finds that there are other more critical mold reservoirs in buildings where mold is detected in the duct system. See Mold in Fiberglass Insulation for details.

Here we include solar energy, solar heating, solar hot water, and related building energy efficiency improvement articles reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.

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FIBERGLASS DUCT, RIGID CONSTRUCTION

Solar Age Magazine was the official publication of the American Solar Energy Society. The contemporary solar energy magazine associated with the Society is Solar Today. "Established in 1954, the nonprofit American Solar Energy Society (ASES) is the nation's leading association of solar professionals & advocates. Our mission is to inspire an era of energy innovation and speed the transition to a sustainable energy economy. We advance education, research and policy. Leading for more than 50 years. ASES leads national efforts to increase the use of solar energy, energy efficiency and other sustainable technologies in the U.S. We publish the award-winning SOLAR TODAY magazine, organize and present the ASES National Solar Conference and lead the ASES National Solar Tour – the largest grassroots solar event in the world."
Steven Bliss served as editorial director and co-publisher of The Journal of Light Construction for 16 years and previously as building technology editor for Progressive Builder and Solar Age magazines. He worked in the building trades as a carpenter and design/build contractor for more than ten years and holds a masters degree from the Harvard Graduate School of Education. Excerpts from his recent book, Best Practices Guide to Residential Construction, Wiley (November 18, 2005) ISBN-10: 0471648361, ISBN-13: 978-0471648369, appear throughout this website, with permission and courtesy of Wiley & Sons. Best Practices Guide is available from the publisher, J. Wiley & Sons, and also at Amazon.com.
Excerpts with updates and annotations expanding the original Best Practices Guide text can be found in the online review and book summary at BEST CONSTRUCTION PRACTICES GUIDE and also at DECK & PORCH CONSTRUCTION, at INDOOR AIR QUALITY IMPROVEMENT GUIDE, and in other articles found at InspectAPedia.com such as HOUSEWRAP AIR & VAPOR BARRIERS, SOUND CONTROL in buildings, and other topics.
AmCraft,Inc., 2311 Mechanic St., Waterville, OH 43566.

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
Environmental Health & Investigation Bibliography - our own technical library on indoor air quality inspection, testing, laboratory procedures, forensic microscopy, etc. Fiberglass in Indoor Air, HVAC ducts, and Building Insulation, Indoor Air Quality Investigations: (this article)
Mold in Fiberglass, when, why, and how fiberglass becomes a reservoir of problem mold in buildings.
Lab Identification of Fiberglass photographs and text assist in laboratory identification of fiberglass fibers and fragments in air, dust, or material samples in the laboratory using forensic microscopic techniques.
Duct System Defects
Fiberglass in Indoor Air, HVAC Ducts, and Building Insulation
Fiberglass Particle Identification in the Fiberglass Test Laboratory
Goodman Gray Flex Duct Deterioration and Failures
Mold in Fiberglass Insulation
Owens Corning Flex Duct Deterioration and Failures

Fiberglass building insulation and HVAC duct work insulation hazards
Fiberglass carcinogenicity: "Glass Wool Fibers Expert Panel Report, Part B - Recommendation for Listing Status for Glass Wool Fibers and Scientific Justification for the Recommendation", The Report on Carcinogens (RoC) expert panel for glass wool fibers exposures met at the Sheraton Chapel Hill Hotel, Chapel Hill, North Carolina on June 9-10, 2009, to peer review the draft background document on glass wool fibers exposures and make a recommendation for listing status in the 12th Edition of the RoC. The National Institute of Environmental Health Sciences is one of the National Institutes of Health within the U.S. Department of Health and Human Services. The National Toxicology Program is headquartered on the NIEHS campus in Research Triangle Park, NC. The National Institute of Environmental Health Sciences is one of the National Institutes of Health within the U.S. Department of Health and Human Services. The National Toxicology Program is headquartered on the NIEHS campus in Research Triangle Park, NC.

Following a discussion of the body of knowledge, the expert panel reviewed the RoC listing criteria and made its recommendation. The expert panel recommended by a vote of 8 yes/0 no that glass wool fibers, with the exception of special fibers of concern (characterized physically below), should not be classified either as known to be a human carcinogen or reasonably anticipated to be a human carcinogen. The expert panel also recommended by a vote of 7 yes/0 no/1 abstention, based on sufficient evidence of carcinogenicity in well-conducted animal inhalation studies, that special-purpose glass fibers with the physical characteristics as follows longer, thinner, less soluble fibers (for 1 example, > 15 μm length with a kdis of < 100 ng/cm2/h) are reasonably anticipated to be a human carcinogen for the listing status in the RoC. The major considerations discussed that led the panel to its recommendation include the observations of tumors in multiple species of animals (rats and hamsters). Both inhalation and intraperitoneal routes of exposure produced tumors, although inhalation was considered more relevant for humans.
Fiberglass insulation mold: occurrence of mold contamination in fiberglass insulation can be impossible to see with the naked eye, but can be significant>
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Rigid Insulating Board Air Conditioning & Heating Duct Construction

Rigid-Insulation Ducts

Technical Opinion About Rigid Fiberglass Ductwork

Advantages of Rigid Fiberglass Duct Board

Disadvantages of Rigid Fiberglass Duct Board

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