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  1. #1
    Join Date
    Feb 2006


    I need to find a forced air furnace make that does not use fibreglass insulation around heat exchanger. This is for a fibreglass sensitive individual.

    The other option would be to replace the insulation in the existing furnace (quite new) but with what? Does anyone know of any material that can be used for that purpose?


  2. #2
    Join Date
    Aug 2006
    Florida (some where) way-south

    Thumbs up

    talk to a sheet-metal shop

    cover fiber-glass with sheet metal liner

    or use mastic fire rated seal fibre-glass

    doing one call at a time.

  3. #3
    Join Date
    Feb 2006
    These ideas are good. Any other solutions?

  4. #4
    Join Date
    Sep 2004

    why not..

    talk to the installer?
    I don’t always drink beer, but when I do I prefer Dos-Equis. I am the most interesting man in the world. Stay thirsty my friends.

  5. #5
    Join Date
    Aug 2002
    There are units that use armor-flex for the cabinet insulation. I don’t know the manufactures off hand. One other option is sealing the glass insulation with a encapsulate. Something like we used on asbestoses insulation.

  6. #6
    Join Date
    Dec 2005
    Cleveland, OH
    Most "builder" line furnaces scrimp by leaving out the insulation in the blower compartments, and most all furnaces I have seen have foil backed insulation in the heat exchanger compartment which would be sealed with fire mastic.

    York had planned to make a fiberglass free 80% furnace with a sheetmetal gap instead of fiberglass in it. I saw a display model at a trade show - I don't know if they are actually producing this furnace or not. Check with the local York/Luxaire dealer.

    Good? Bad? I'm the guy with the gun.

  7. #7
    Join Date
    Feb 2006
    I was very surprised to see fiberglass to shade fine dust in a one year old furnace. According to my research and visual inspection confirms this fiberglass after some heat exposure is very brittle and easily breaks into fibers of less than 1 micron in size (very dangerous dust).

  8. #8
    Join Date
    Oct 2003
    I think you are over-analyzing things and are paranoid about it. Don't you have something more important to worry about? Get a good filter and you'll(customer), will be fine.

  9. #9
    Join Date
    Feb 2006

    I am just getting educated not over analyzing. I think ignorance is dengerous. Read this and look at references at the bottom:

    Owens Corning's Fiberglas ®, Fiber Glass, Glass Fiber and GlassWool: A Carcinogen That's Everywhere - The Asbestos of the 21st Century
    Rachel's Environment and Health Weekly [1]


    An industrial process for making glass fibers was first patented in Russia in 1840. [1,pg.292] At the Columbian Exposition in Chicago in 1893, Edward Libbey, an American, exhibited lamp shades, a dress, and other articles woven from glass fibers. In 1915, the Allied Forces blockaded Germany and created an asbestos shortage which resulted in full-scale U.S. production of fiber glass as an asbestos substitute.

    Asbestos is a naturally-occurring fibrous material that can be woven into cloth, does not burn readily, has excellent properties for thermal insulation, and therefore came into common commercial use during this century.[2,pgs.390-392] Fiber glass has many of the same characteristics as asbestos.

    In 1938, the Owens Corning Fiberglas Company was formed, and three years later, in 1941, evidence of pulmonary disease was reported by Walter J. Siebert, who investigated the health of workers with the cooperation of Owens Corning.[1,pg.292] That same year another investigator reported finding "no hazard to the lungs" of workers exposed to glass fibers in the air. Scientific disagreement of this sort has characterized the study of fiber glass ever since; meanwhile fiber glass production has increased steadily.

    In 1941, the U.S. Patent Office issued patents for 353 glass wool products. Glass wool, fiber glass, fiberglas, fibrous glass, and glass fibers are all names for the same thing: man made thin, needle-shaped rods of glass.

    Fiber glass is now used for thermal insulation of industrial buildings and homes, as acoustic insulation, for fireproofing, as a reinforcing material in plastics, cement, and textiles, in automotive components, in gaskets and seals, in filters for air and fluids, and for many other miscellaneous uses. More than 30,000 commercial products now contain fiber glass.

    As asbestos has been phased out because of health concerns, fiber glass production in the U.S. has been rising. In 1975, U.S. production of fiber glass was 247.88 million kilograms (545.3 million pounds); by 1984 it had risen to 632.88 million kilograms (1392.3 million pounds).[1,pg.302] If that rate of growth (10.4% per year) held steady, then production of fiber glass in the U.S. in 1995 would be 436 million pounds.

    Fiber glass is now causing serious health concerns among U.S. officials and health researchers. Dr. Mearl F. Stanton of the National Cancer Institute found that glass fibers less then 3 microns in diameter and greater than 20 microns in length are "potent carcinogens" in rats; and, he said in 1974, "it is unlikely that different mechanisms are operative in man." A micron is a millionth of a meter (and a meter is about three feet). Since that time, studies have continued to appear, showing that fibers of this size not only cause cancer in laboratory animals, but also cause changes in the activity and chemical composition of cells, leading to changes in the genetic structure in the cellular immune system. Although these cell changes may be more common (and possibly moreimportant) than cancer, it is the cancer-causing potential of glass fibers that has attracted most attention.

    In 1970, Dr. Stanton announced that "it is certain that in the pleura of the rat, fibrous glass of small diameter is a potent carcinogen." The pleura is the outer casing of the lungs; cancer of the pleura in humans is called mesothelioma and it is caused by asbestos fibers. Stanton continued his research and showed that when glass fibers are manufactured as small as asbestos fibers, glass causes cancer in laboratory animals just as asbestos does. [4] Asbestos is a potent human carcinogen, which will have killed an estimated 300,000 American workers by the end of this century. [5] The finding that fiber glass causes diseases similar to asbestos was chilling news in the early 1970s, and an additional 25 years of research has not made the problem seem less serious. Workers in fiber glass manufacturing plants are exposed to concentrations of fibers far lower than the concentrations to which asbestos workers were exposed, yet several industry-sponsored epidemiological studies of fiber glass workers in the U.S., Canada, and Europe have reported statistically significant elevations in lung cancers. [6]

    The International Agency for Research on Cancer (IARC), of the World Health Organization, listed fiber glass as a "probable [human] carcinogen" in 1987. In 1990, the members of the U.S. National Toxicology Program (NTP)-representatives of 10 federal health agencies-concluded unanimously that fiber glass "may reasonably be anticipated to be a carcinogen" in humans. NTP members were preparing to list fiber glass that way in the Seventh Annual (1992) Report on Carcinogens, the NTP's annual listing of cancer-causing substances, which is mandated by public law 95-622. But industry intervened politically.

    Four major manufactures of fiber glass insulation campaigned for three years to prevent their product from being labeled a carcinogen by NTP. They managed to delay the publication of the NTP's Seventh Annual Report on Carcinogens for more than two years, but on June 24, 1994, the Secretary of Health and Human Services (HHS), Donna E. Shalala, signed the Report and sent it to Congress, thus making it official policy of the U.S. government that fiber glass is "reasonably anticipated to be a carcinogen." In the U.S., fiber glass must now be labeled a carcinogen.

    Announcing this decision, government officials tried to play down its significance. Bill Grigg, a spokes-person for the U.S. Public Health Service (a subdivision of Health and Human Services) told the Washington Post ,"There are no human data I'm aware of that would indicate there's any problem that would involve any consumer or worker." [7] To make such a statement, Mr. Grigg had to ignore at least six epidemiological studies showing statistically-significant elevations in lung cancers among production workers in fiber glass factories.[6] Indeed, according to researchers fiber glass is a more potent carcinogen than asbestos.[8,pg.580]

    Fiber glass is now measurable everywhere in the air. The air in cities, rural areas,[1,pgs.311-314] and remote mountain tops [4] now contains measurable concentrations of fiber glass. If the dose-response curve is a straight line (that is to say, if half as much fiber glass causes half as much cancer) and if there is no threshold dose (no dose below which the cancer hazard disappears), then exposing the Earth's 5.7 billion human inhabitants to low concentrations of fiber glass will inevitably take its toll by causing excess cancers in some portion of the population.

    According to OSHA researchers, an 8-hour exposure to 0.043 glass fibers per cubic centimeter of air is sufficient to cause lung cancer in one-in-every-thousand exposed workers during a 45-year working lifetime.[8,pg.580] In rural areas, the concentration of fiber glass in out-door air is reported to be 0.00004 fibers per cubic centimeter, about 1000 times below the amount thought to endanger one-in-every-thousand fiber glass workers.[1,pg.314] But people in rural areas breathe the air 24 hours a day, not 8 hours. Furthermore, a human lifetime is 70 years, not the 45 years assumed for a "work lifetime." Moreover, one-in-a-thousand is not adequate protection for the general public; U.S. Environmental Protection Agency uses one-in-100,000 or one-in-a-million as a standard for public exposures. (And in urban air, there's 10 to 40 times as much fiber glass as in rural air.) Therefore, the amount of fiber glass in the outdoor air in the U.S. and Europe (and presumably elsewhere) already seems higher than prudent public health policies would permit. Assuming a straight-line dose-response curve and no threshold, there is ample reason to be concerned about the human health hazards posed by fiber glass in the general environment.

    It has been 25 years since researchers at the National Cancer Institute concluded that fiber glass is a potent carcinogen in experimental animals. During that time, additional research has confirmed those findings again and again.[8] During the same period, the amount of fiber glass manufactured has increased rapidly year after year. Ninety percent of American homes now contain fiber glass insulation. All of this fiber glass will eventually be released into the environment unless special (and very expensive) precautions are taken to prevent its release. The likelihood of Americans taking such precautions is nil. Billions of pounds of fiber glass now in buildings will eventually be dumped into landfills, from which it will leak out slowly as time passes. Elevated concentrations of fiber glass are already measurable in the air above landfills today.[4]

    In 1991, Patty's Industrial Hygiene and Toxicology, a standard reference book on work-place safety and health, said about fiber glass, " is prudent for industrial hygienists to treat these materials with the same precautions as asbestos." [1,pg.324] How do we treat asbestos? In the U.S., all new uses of asbestos have been banned. A ban of fiber glass is long overdue.


    [1] This article was researched and authored by Rachel's Environment and Health Weekly, June 1, 1995 edition and published by the Environmental Research Foundation which provided the research and substance of this article. The ERF deserves your support for its commitment to a national environmental policy which makes health risks to people a national priority and for its commitment to public education. The ERF not only allows the re-distribution of its research and articles, but encourages it. We have only the highest praise for ERF and its work. We encourage you to subscribe to Rachel's Weekly. Email, call 410.263.1584, or fax 410.263.8944. We strongly recommend Maria Pellerano's How to Research Chemicals: A Resource Guide, which is available for $10 from ERF. It is a must for all researches and is excellent!


    [1] Jaswant Singh and Michael A. Coffman, "Man-Made Mineral Fibers," in George D. Clayton and Florence E. Clayton, editors, Patty's Industrial Hygiene and Toxicology Fourth Edition, Volume 1, Part B (New York: John Wiley & Sons, 1991),pgs. 289-327.
    [2] Michael A. Coffman and Jaswant Singh, "Asbestos Management in Buildings," in George D. Clayton and Florence E. Clayton, editors, Patty's Industrial Hygiene and Toxicology Fourth Edition, Volume 1, Part B (New York: John Wiley & Sons, 1991), pgs. 387-420.
    [3] The Annual List of carcinogens is drawn up by an inner-agency Working Group for the Annual Reports on Carcinogens, which includes representatives from the Agency for Toxic Substances and Disease Registry (ATSDR); the Centers for Disease Control (CDC); the National Institute for Occupational Safety and Health (NIOSH); the Consumer Product Safety Commission (CPSC); the U.S. Environmental Protection Agency (EPA); the Food and Drug Administration (FDA); the National Cancer Institute (NCI); the National Institute of Environmental Health Sciences (NIEHS); the National Library of Medicine (NLM); and the Occupational Safety and Health Administration (OSHA).
    [4] Reported in Katherine and Peter Montague, "Fiber Glass," Environment Vol. 16 (September 1974), pgs. 6-9.
    [5] Philip J. Landrigan, "Commentary: Environmental Disease-A Preventable Epidemic," American Journal of Public Health Vol. 82 (July 1992), pg. 941.
    [6] See Peter F. Infante and others, "Fibrous Glass and Cancer," American Journal of Industrial Medicine Vol. 26 (1994), pgs. 559-584, which reviews the following studies, among others: L. Simonato and others, "The International Agency for Research on Cancer Historical Cohort of MMMF Production Workers in Seven European Countries Extension of the Follow-Up," Annals of Occupational Hygiene Vol. 31, No. 4B (1987), pgs. 603-623; Philip E. Enterline and others, "Mortality Update of a Cohort of U.S. Man Made Mineral Fibre Workers," Annals of Occupational Hygiene Vol. 31, No. 4B (1987), pgs. 625-656; Harry S. Shannon and Others, "Mortality Experience of Ontario Glass Fibre Workers-Extended Follow-UP," Annals of Occupational Hygiene Vol.31, No. 4B (1987), pgs. 657-662; and John R. Goldsmith, "Comparative Epidemiology of Men Exposed to Asbestos and Man-Made Mineral Fibers," American Journal of Industrial Medicine Vol. 10 (1986), pgs. 543-552; G.M. Marsh and Others, "Mortality Among a Cohort of US Man-Made Mineral Fiber Workers : 1985 Follow-Up," Journal of Occupational Medicine Vol. 32 (1990), pgs. 594-604; P. Boffetta and others, "Lung Cancer Mortality Among Workers in the European Production of Man-Made Mineral Fibers-A Poisson Regression Analysis," Scandinavian Journal of Work, Environment, and Health Vol. 18 (1992), pgs. 279-286.
    [7] Frank Swoboda and Maryann Haggerty, "U.S. Suspects Figerglass as Carcinogen, Calls Insulation Safe," Washington Post July 2, 1994, pg. C1.
    [8] Peter F. Infante and others, "Fibrous Glass and Cancer," American Journal of Industrial Medicine Vol. 26 (1994), pgs. 559-584.

  10. #10
    Join Date
    Feb 2006
    Float'N Vally, MS
    Rachel's Environment and Health Weekly [1]!!!!

    I don't really buy this.....
    When I was growing up we wadded ankle deep thru the nasty stuff in Dad's shop. None of us or the helpers have had cancer problems (over thirty years). Of course this could be just luck.

    Maybe this is why Rheem AHU's have a sticker on them stating that the fiberglass in their units may cause cancer in CALIFORNIA!

    but Really... For people with allergies and other problems we do total sheetmetal jobs with insluation on the outside (no insluation in the inside of the ductwork. As far as the insluation in the units (on the newer units) the insluation is toward the metal and the foil is toward the air stream. Not really a concern.
    Life is too short, Behappy!

  11. #11
    Join Date
    Oct 2001
    Waterford Michigan
    A scientific working group of 19 experts from 11 countries convened by the Monographs Programme of the International Agency for Research on Cancer (IARC) has concluded its re-evaluation of the carcinogenic risk of airborne man-made vitreous fibres.

    Man-made vitreous fibres in the form of wools are widely used in thermal and acoustical insulation and in other manufactured products in Europe and North America. These products, including glass wool, rock (stone) wool, and slag wool, have been in use for decades and have been extensively studied to establish whether fibres that are released during manufacture, use, or removal of these products present a risk of cancer when inhaled. Epidemiologic studies published during the 15 years since the previous IARC Monographs review of these fibres in 1988 provide no evidence of increased risks of lung cancer or of mesothelioma (cancer of the lining of the body cavities) from occupational exposures during manufacture of these materials, and inadequate evidence overall of any cancer risk.

    Beside this, much industrial effort has gone into development of newer materials that have similar insulation properties to the older products, but which disappear from body tissues much more rapidly. The reason for this effort is that asbestos, a known human carcinogen which causes both mesothelioma and lung cancer and had been used as insulating material for several decades, is extremely slow to decompose and disappear from body tissues in which it has been deposited. This characteristic, known as high biopersistence, is correlated with the high carcinogenic potency of asbestos fibres. Some of these newer materials have now been tested for carcinogenicity and most are found to be non-carcinogenic, or to cause tumours in experimentals animals only under very restricted conditions of exposure.

    The Monographs working group concluded that only the more biopersistent materials remain classified by IARC as possible human carcinogens (Group 2B). These include refractory ceramic fibres, which are used industrially as insulation in high-temperature environments such as blast furnaces, and certain special-purpose glass wools not used as insulating materials. In contrast, the more commonly used vitreous fibre wools including insulation glass wool, rock (stone) wool and slag wool are now considered not classifiable as to carcinogenicity to humans (Group 3). Continuous glass filaments, which are used principally to reinforce plastics, are also considered not classifiable as to carcinogenicity to humans.

  12. #12
    Join Date
    Nov 2000
    Eastern PA
    Certain special interest organizations have been going after fiberglass for 5 decades now. Sheet metal unions are the largest proponents of poo-pooing fiberglass with so called health goofs not far behind.

    So far, not one bit of evidence proves that fiberglass is the menace that some have claimed it to be.

    There are factors about fiberglass that need to be addressed however. Dust, mildew etc. will accumulate on fiberglass products and can certainly cause issues, especially with those who have resporatory sensitivities...such as I have.

    Fiberglass in itself is clean. Microscopic fibers that become so small as to be able to become airbourne will pass through the resporatory system doing no harm, just as billions of other things we breath daily do.

    The "evidence" of fiberglass breaking down on regesters is most likely not fiberglass residue or even coming from the HVAC air system. When shadowing materials build up on vents and in air patterns on walls, ceilings and floors from vents, it is usually dust, smoke or other airbourne items int the room that are attracted to the electrostatic charge created by the air from the vent passing over the affected material.

    Keep your air filters clean. Seal off any openings that would allow unfiltered air to enter the HVAC system, even screw holes. Keep artificially/chemical scented items out of your home. Do not burn candles and try to bring in outside air into your home and you will be a lot better off then trying to pinpoint one item, such as fiberglass, for all of your woes.
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV

  13. #13

    I agree with 1972torino. Also, some HVAC "showrooms" have models on display and you could see which models do or do not have fiberglass.

    As a homeowner, I have followed the routine maintenance for my xv80 furnace. This includes vacuuming near the burners.

    As I had the furnace circuit breaker turned off, I noticed that there is a fiberglass pad in the compartment where the blower wheel is. A pad covers all of the fiberglass EXCEPT the edges.

    On my model of furnace, the fiberglass is downwind of the filter. So, I plan to ask my HVAC contractor if they could put heavy-duty metal foil tape to cover the fiberglass. This looks like it could be done without disassembling any of the parts.

    I only have a small section of fiberglass insulated flex duct between the (metal duct) cold air return and the furnace. I don't have rats or mice. However, at least any potential flex duct fiberglass disruption would be upwind of the filter. I may have this flex replaced. Fiberglass is irritating on the skin (anyone disagree???). I may consider having metal ducts sealed and then adding insulation on the outside of the ducts.

    I feel safe having fiberglass insulation in my attic and walls. However, it does seem unwise to have exposed fiberglass in a furnace or an air handler (lots of airflow). I have not had the fiberglass in my furnace sealed yet. Thanks for the reminder.

    I have an environmentalist relative who reads Rachel's Report and forwarded an article on plastic wraps in microwaves! I would still recommend the Trane xv80 furnace to them (American Standard/Trane furnace high reliability per Consumer Reports). For additional energy conservation, I also have a high seer/hspf heat pump.

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