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Community and Q&A

Non-toxic ductwork

Evan&Suzy | Posted in Green Products and Materials on

We are researching truly non-toxic ductwork for our all new electric heating/cooling… HVAC system. We are only finding the usual hardpipe which is known to be coated on inside with rust proofing, and the flex. The flex is found to be polyester and nylon in the interior with a wrap of insulation, probably but we’ve not been able to find that info yet, probably has fire retardant and formaldehyde, and who knows what. then the outer black plastic layer or silver whichever, silver would be best as all plastics outgas toxic fumes and when heated… even moreso. If someone could please point us to some truly non toxic ductwork… for a chemically sensitive person. Most normal people wouldn’t notice but all of us do, and must have all the toxic chemicals out of the line of fire, so to speak, as best we can. Thanks for any suggestions at all.

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  1. User avatar GBA Editor
    Martin Holladay | | #1

    Evan and Suzy,
    Galvanized steel ductwork, to the best of my knowledge, is simply steel coated with zinc. When I was growing up, every bucket and bathtub on every farm in America was made of galvanized steel, and I never heard that galvanized steel was considered toxic. (Actually, some farm buckets included lead solder, and lead solder was a bad idea. But I can assure you that lead solder is never used for ductwork.)

    Many older homes have water pipes made of galvanized steel.

    I don't think that galvanized steel ductwork is coated on the inside, but I suppose you could have your contractor wash each piece of ductwork with soap and water before it is installed -- assuming, of course, that you can tolerate some kinds of soap.

  2. User avatar GBA Editor
    Martin Holladay | | #2

    Evan and Suzy,
    One more point: In general, ductwork is non-toxic -- which is to say, there are no reports of homeowner poisoning related to ductwork installed in their homes.

    You've described yourself as "chemically sensitive." That means that there really are no rules that apply -- only you know what you can tolerate. You'll have to experiment; I don't know of any other way to determine what sets off a reaction in a person who is chemically sensitive.

  3. Andrew C | | #3

    If you are at the design stage, why not consider eliminating ductwork? Ductless minisplits are often a good solution, especially if you are all electric.

  4. User avatar GBA Editor
    Martin Holladay | | #4

    Evan and Suzy,
    As Andrew noted, it's possible to have a duct-free house.

    For heating and cooling, use ductless minisplits.

    For ventilation, use Lunos fans.

  5. Benoit Aspirault | | #5

    Hi Martin, you may want to look at this recent research

    However, historical research documents that the grade of zinc typically used for galvanizing contains a minimum of 0.5% lead and can itself be a significant long-term source of lead, which may explain some recent lead contamination problems associated with galvanized steel

    Not to be confused with the actual question which relate to air contamination and not water.

    For the actual question, it might also be hypochondria, which can't be resolved with any type of duct material.

  6. User avatar GBA Editor
    Martin Holladay | | #6

    I appreciate the link. Lots of older homes I've worked on in this part of Vermont have galvanized water supply pipes. My family often hauled water in galvanized buckets when we went camping as kids.

    I guess that means I would have been a little bit smarter if only there was less lead in the water I drank as a child.

    Still, as you point out, I've never heard of any poisoning caused by galvanized ducts.

  7. Jon Harrod | | #7

    I've noticed a light oily coating on adjustable sheet metal parts like elbows--presumably there to prevent corrosision and binding. One chemically-sensitive customer we worked with asked that the ductwork be washed with soap prior to installation. If you're committed to a ducted system, I'd recommend buying a couple sheet metal elbows, washing them, and seeing if they bother you. Once the oils are removed, you should have a durable, inert distribution system.

    That being said, I'd also echo the recommendation to explore a ductless solution.

  8. User avatar
    Jon R | | #8

    As far a I know, steel, zinc and even lead don't off-gas at all at duct temperatures, leaving only mastic as a possible concern. Contact with drinking water is quite different than air.

  9. Evan&Suzy | | #9

    Thank you all for your helpful replies. Looks like Jon Harrod is the only one with experience working with chemically sensitive customers. This I can attest is a living hell worse than death, the blessing, with the situation such as it is with the above the norm. 'No one's ever heard of anyone being poisoned,' and so on. No one's ever heard of US testing gadgets being 1000 points lower, at least for carbon monoxide and gas, than the European testing devices, because that information is not advertised here. I can't find the article so don't quote me but that's what I recall from an article in Our toxic Times, years ago now, and nothing has changed here to date as far as I know. I'm suffering another gas and carbon monoxide exposure, yes, another, due to yearly maintenance not having caught the problem soon enough, again, so I'm not able to do any digging with life saving measures again taking up all my time. See also: and so many others I couldn't remember a fraction of them. We don't have the toxicity information we need because no one's ever tested it. When toxic injury comes on imperceptibly, incrementally, one would not notice, then... bam. Of course the medical establishment won't have a clue unless one connects with a chemical injury physician, a growing profession these days. No one's tested any of these duct products for long term accumulation of poisons therein so there is no data. The oil on the galvanized steel is probably rust proofing. That is NOT non toxic. Mastic is NOT non toxic. But there are other 'mastic' products now what are 0_VOC. I tested the flex duct via 3 different modalities and as injured as I am right now, I reacted to it badly. I will have to find out if we can do the ductless mini splits which is probably the best deal. We did have to wash that 'oily' coating off metal when this furnace was installed in 2003, but I wouldn't know if that bothered me, us, because the gas valve stuck open for 3 months. I was fighting about it going down the tubes along with Evan, in denial as most men always are, and finally somehow managed to call the gas company. The division manager himself came out and found the gas valve had stuck open the entire 3 months while I was getting the nutcase and 'hypochondriac' rackets run on me, us... The division manager said, 'its a miracle it didn't explode.' Evan didn't even know where he was, driving to town, going east west trying to get to a northerly destination, screaming at me as if I was telling him the wrong way to go. That's men. Even with 10 prior years of the same, different materials, like OSB, supposed to have been taken off market... I was doing so well before that gas leak and have been unable to gain the degree of recovery from the initial death and back status i suffered, that I enjoyed before the gas 3 month gas leak. I've suffered 24 years of repeated chemical injury from different poisonous sources, some of which have been taken off the market since, but i got the nutcase routine run om me, like most women and children, every time. But every time I was right, and there really was something seriously poisonous in our small house, and I proved it with tests on the house, the offending whatever it was, any myself, thereafter, available upon request. That said, it would be a good idea to rethink this entire situation and come up with duct work that is truly NON toxic, even if most people think they are doing OK with the status quo. So many people and children suffer from Asthma, COPD, cancer, brain and nerve related issues without a cause. It's always the illusive obvious. I've come up with a readily available material for duct work that could hit the 'green' and' healthy hous'e markets immediately. If there is anyone out there who would like to help me get this going, that usually means funding and startup, all that, I'd appreciated it. So far, I've given all my grand ideas away which went into not millions but billion dollar sales on one idea, and I'm not doing that again since I was not able to claim compensation for most of the chemical injuries I suffered during this new construction and remodeling nightmare. Please see all the links above and links they provide. MCSRR has profound info on CO, and a lower range CO tester, so that's a do not miss. Thank you all so much for your replies. It's time to take indoor air quality to the next level... something on the order of what NASA is using for the astronauts in space and space station. The Mitsubichi ductless is one, as I recall. I was going to check on what they're using for duct work today... I'll let you know. Thanks again.

  10. Malcolm Taylor | | #10

    Evan and Suzy,

    The CMHC (Canadian Mortgage and Housing Corporation) has done a lot of work on housing and environmental sensitivities, including building units for those suffering from the affliction. You may find a search for CMHC + chemical sensitivities or something similar would yield some useful advice.

  11. Evan&Suzy | | #11

    Thank you, Malcom Taylor, and everyone above. I'm not finding materials info for NASA's ISS. I'll see if I can find the CMHC + chemical sensitivities you offered. I've emailed our contractor with all your info and suggestion on the ductless mini split. We'll see what he says. I'm having another bad reaction about something since yesterday afternoon with the cause still at large, so, this is a good time for those who offered their kind replies above to get a glimpse into what a hell this is. More and more people are joining the ranks and most contractors green or otherwise don't know how to handle it. Martin, et al, I truly appreciate the offerings. I'm checking out the Lumos fans now. I hope our contractor is up to speed. Sorry about the long post, but tells the tale of this horrid 24 year nightmare and how to live through it. Testing out each product is the only way as everyone is 'party specific.' But even testing, a little used in a test is not the same as a ton of it installed. And it's always too late after the fact. I'm having trouble understanding lumos fans with the brain damage... and everything else for that matter. I need someone in here to do this for me while I get treatment at a bona fide chemical injury clinic for once. The galvanized duct is an extra $4000. How can I afford it? Is there financial help for people like me?

  12. Evan&Suzy | | #12

    Thanks, Malcom. I found this. I'll contact them and see if they have suggestions for non toxic duct work. The galvanized seems best if I can't do the ductless for some reason.

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