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  1. #14
    Join Date
    Jul 2002
    Location
    Yuma, AZ
    Posts
    2,361
    Interesting. The Ford evaporator is probably an all aluminum coil and the irritant is the flux used to bond the aluminum to itself during manufacturing: Chemical: Aluminum Potassium Fluoride In Ford's case, the coil was not properly cleaned and defluxed during the manufacturing process. The coil itself is not degrading and producing the white powder.

    The white powder you are seeing may not have the same chemistry and may or may not be hazardous. Is the coil under warranty? If so, the manufacturer needs to hear of this problem and may have an understanding of it already. Talk to them. You will need the coil model and serial number to expedite the discussion.
    "I have never let my schooling interfere with my education."
    Mark Twain
    More at: http://www.quotationspage.com/subjects/education/

  2. #15
    Join Date
    Oct 2011
    Posts
    13
    Thank you by the way for your commentary. I do not know anyone else that can help me figure this out, including several govt agencies and several experts in the field. Take a look at this commentary I found on another blog.... it was on a technical website and the jargon is a little tough for me to understand but it seems to be exactly what I am experiencing

    Hello,
    We're experiencing a serious non-conformance events that inspector has found out some unkown powder were blowing out of room vents, which dropped on the floor like floc, and it could be pressed and grinded into white powder by your fingers.
    Air is humidified and filtered(H14) after output, several days before we ever increased the air press to meet
    the requirements of rooms air flow criteria.

    We're wondering what the powder is. and where it from?

    Who could help me on this? Looking forward to.....

    Borjn Zh

    Thank zhangbd
    for this valuable post!


    Is your system once through or recirculatory? Where are you finding this powder, in the exhaust or in the controlled space? What are you manufacturing? What is the position of room return(floor level or ceiling level)? Are the filters integrity tested? What is the function in areas adjacent to this controlled room?

    Regards,


    Thank quark
    for this valuable post!

    zhangbd (Chemical)
    19 Sep 05 3:53
    Dear quark,

    Thanks for your concern, That HVAC is once through system, we are finding this powder on the floor,and also on the material bags, seems everywhere in the controlled area. The return points are at the floor level, and we conduct integrity test annually by third-party service. We are a pharmaceutical plant and this controlled room is weighing area, supplied by this hvac separately.

    Now we're doubt whether this unknown powder coms from HEPA? Maybe high face velocity ruptured the fiberglass, we're checking the HEPA....

    Thanks for your further guides

    Thank zhangbd

    quark (Mechanical)
    19 Sep 05 5:07
    All dispensing areas should be negative w.r.to the adjacent areas and I presume you meet this requirement. Further, you should carryout dispensing in a reverse down flow laminar booth. The powder may either be excipient or active ingredient.

    This is not a problem with HEPA filters.

    Check your return risers for presence of this powder. If you find traces then the velocity in the return may not be sufficient.

    Next time, try the dispensing activity in a closed booth and check for the presence of this powder outside.

    Regards,

    Thanks very much, quark and tbrght:

    We have tried out every repair to indentify root cause: clean out the duct, change all of HEPA, and even check& clean all damps on duct, but the unkown white powder still blow out continually.

    is it zinc oxide? i think the high humudity air throgh the long galvanized duct may increase its oxidating speed.

    regards
    I've seen a similar problem in a pharmaceutical building. The problem was bad air handling unit design. Here was what happened:

    The outside air intake on the 100% OA system was of fairly high velocity and occasionally took in snow and rain. The filter media frequently became wetted, and released some of the liquid onto the heating coil just downstream.

    Due to the make-up of the filters, droplets of water from these wetted filters contained high levels of chloride, sulfate, and phosphate. The heating coil, wetted with this solution, rapidly evaporated the water, forming concentrated pockets of corrosives on the aluminum coil fins.

    Accelerated coil corrosion results in formation of aluminum oxide chips, which look like particles of dandruff when they fall onto surfaces.

    My guess is that some phenomena, either a situation as I just described, or an improperly controlling humidifier corroding a heating coil, is creating the condition you describe.



    Very thanks to everyone for your concern,

    Colleagues from lab said this unkown white powder is aluminum oxide, so till to now, we can make a conclusion to this case, even though which has brought us so much trouble.

    It's caused by bad AHU designed, like ChasBean1 described above, the air downstream the humidifier with high velocity and nearly 90% humidity occasionally has corrosive action to the aluminum galvanized duct, on the surface, points there are rivets and cutted holes for valves installation always are weakly to anti-corrosion, so results in aluminum oxide formed on and be blown down to controlled area, looks like particles of dandruff.

    Too long duct installed downtream the humidifier causes to form this white aluminum oxide. We have inquired about this case to some consultant firms for betterments, they suggested we should modify existing AHU layout and put the HEPA at the vents in accordance with the cGMP.

    I also think this problem is normally to each HVAC, so I want draw everyone full attention on this case.

    Thank zhangbd
    for this valuable post!


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    If so, Red Flag it!


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    area for this forum!

    SAK9 (Mechanical)
    31 Oct 05 0:12

    In my earlier days, we used to fabricate clean room ducts using aluminium(usually one gauge higher than recommended by the stds such as SMACNA for better strength).That does not seem to be case now.

    I beleive that they use zinc for galvanization of metal sheets.So it could be the AHU coil aluminium fins giving away as suggested by CB.

    Thank SAK9
    for this valuable post!


    Inappropriate post?
    If so, Red Flag it!


    Check out the FAQ
    area for this forum!

  3. #16
    Join Date
    Oct 2011
    Posts
    13
    The first goodman did this and this is a brand new goodman unit and it is doing the same thing. I will press harder but they are saying it is enviornmental not equipment. I guess I will know more after the test comes back. After reading that last post I think the test is going to come back Aluminium Oxide.

  4. #17
    Join Date
    Jul 2002
    Location
    Yuma, AZ
    Posts
    2,361
    Me too. I have seen this in food storage (walkins and refrigerators) in restaurants. Especially where lemons and onions were stored in open containers. (Environmental.)
    "I have never let my schooling interfere with my education."
    Mark Twain
    More at: http://www.quotationspage.com/subjects/education/

  5. #18
    Join Date
    Oct 2011
    Posts
    13
    Lynn,
    Test came back 100% aluminum Oxide. The chemist said an acid or a base will eat the aluminum. I am off to get a pool tester kit to find out if the insulation, fiberboard or anything else I can find is either acidic or basic. Any other ideas? Let you know what I find.

  6. #19
    Join Date
    Oct 2011
    Posts
    13
    I had a guy name Dan Baxter in California test it for me. It came back as Aluminum Oxide. I am having the fiberboard material tested for PH. He tells me anything that has a high or low PH (acid or base) will corrode Aluminum and produce AO. He did not think it would be the fiberglass fiberboard but I am going to have it tested anyway. I hope that is the culprit and I can just have it replaced with metal and be done with this nightmare.

  7. #20
    Join Date
    Jul 2002
    Location
    Yuma, AZ
    Posts
    2,361
    Test: Find a way to bubble some air in your home through some distilled water for a day or two. Then test the PH of the water. The test may need to be repeated if the source is on again - off again in its nature.

    You don't have an indoor spa. Right?
    A few years ago Chinese drywall used in new construction was a disaster.
    You are on the right track.
    "I have never let my schooling interfere with my education."
    Mark Twain
    More at: http://www.quotationspage.com/subjects/education/

  8. #21
    Join Date
    Oct 2011
    Posts
    13
    Distilled water from the jug is giving me a PH reading of 5. The litmus paper I have only has a range of 5-9. I don't understand why the water is so acidic.

  9. #22
    Join Date
    Oct 2011
    Posts
    13
    apparently a common problem with distilled water. Have to have some baking soda to get the PH back to 7 (stable) first. Apparently it is slightly acidic with it hits the air. OK, so i tested the fiber board. Nothing. stable as can be. I haven't tested the essential oils yet but that has to be it, even though Chemist Dan who tested the white powder said it is unlikely to be the culprit. But when you burn essential oils it produces a smoke that goes right over the coils if you have placed it next to a return. What is in that smoke? Like you were suggesting I could put a bowel near the smoke and channel the smoke toward the water and see if it makes the water acidic? I will give that a try.

  10. #23
    This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread.

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    Last edited by jpsmith1cm; 01-22-2013 at 06:42 PM. Reason: non AOP member

  11. #24
    Join Date
    Mar 2004
    Location
    Illinois
    Posts
    6,959
    Quote Originally Posted by OML View Post
    Did your office undergoe a remodel involving sheetrock replacement prior to this problem? There have been links to Chinese drywall and the chemical composition therein causing A/C components to corrode in the way you are describing.
    Good luck with a response...this thread is over a year old.

  12. #25
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    24,982
    OML

    This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread.

    You can find the rules for posting and qualifications here.

    Additional infractions may result in loss of posting privileges.

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