White Powder coming out of Ducts??

[edspace]

I own a commercial office space, a small one, in North GA. It is a one ton unit. I had some white powder coming from the evaporator coil through the ducts and onto the desks and floors. I had the entire unit replaced and 1 year later it came back. I have checked all the obvious things. I have replaced duct work, replaced filters, checked returns, in addition to replacing the air handler and A coil. My HVAC guy has asked numerous experts in the field including a Goodman tech without any help. At this point we are trying to clean the coil and hope it doesn't come back. So far those attempts have yet to be successful. Ever seen this? Any idea what it is? It is a white powder and not building materials or paper. It forms on the coil the office space is very clean an nothing to my knowledge is being sucked into the unit.

[Stamas]

Please do not make duplicate threads.

[edspace]

sorry... new to all this. I thought I was approaching 2 different groups. The residential and commercial forums. I defiantly don't want to tick off the people I'm asking advise from. now I don't know how to delete my second post

[martin&sonsa/c]

man you have an awesome a/c system its actually blowing out snow flakes LOL!!!!

[lynn comstock]

Normal oxidation of aluminum creates an invisible protective coating on the aluminum.

Check the white corrosion of aluminum info at http://1st-coating.com/corrosion_alloys.htm.

Chemical reactions to air contaminants may be causing this. It would be good to check the equipment grounding circuit because electrical charges on the metal surface accelerate corrosion processes.

[edspace]

You seem to have a high level of knowledge on this. Have you ever seen or heard of this problem? I have yet to find someone that has experienced this or found a solution. I have had numerous veteran contractors come look at it and none can give me an explanation. Really puzzling. I will have my HVAC guy check to see if it is grounded properly. Thanks for your input.

[lynn comstock]

A common source of chemical contaminants is cleaning products. If you are using a commercial cleaning service, their products are often "stronger" than products used in homes because they save time. Pay paricular attention to floor cleaning products.

[FL.HVAC]

Normal oxidation of aluminum creates an invisible protective coating on the aluminum.

Check the white corrosion of aluminum info at http://1st-coating.com/corrosion_alloys.htm.

Chemical reactions to air contaminants may be causing this. It would be good to check the equipment grounding circuit because electrical charges on the metal surface accelerate corrosion processes.

That was my thought.
OR!
Anthrax!!!!

(JK)

[edspace]

We do not have a professional cleaning service and use normal household cleaning supplies. The only thing I can think of out of the ordinary are the essential oils that a lady in my office often burns with a candle. Do you think those oils could be causing the problem?

[lynn comstock]

...Do you think those oils could be causing the problem?

Who knows? Something is going on. For all I know contamination may be from outside. Air conditioning equipment installed near the ocean corrodes badly because of sea salt in the air from ocean water spray. (As an example that is well documented.)

The other possibility is the electrical grounding of the equipment isn't working properly, and that needs to be checked out.

[edspace]

I have tried everything.....Time to get OSHA involved.

[lynn comstock]

Collect some powder and have it chemically analyzed if you are serious. With mass spectrometry it doesn't take much of a sample.
http://en.wikipedia.org/wiki/Mass_spectrometry

[edspace]

we were thinking the same thing, ok I have collected a sample and am ready to send it off to EMSL they said it would be $550 - $700 for tests to discover what this stuff is. Any other suggestions? of places to get it tested. Seems expensive.

I did find this of interest. This website talks about a known problem with Ford cars Ford only says it "may be caused by flux utilization of the evaporator coil"
http://www.ford-white-dust.com/

[lynn comstock]

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.

[edspace]

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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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!


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[edspace]

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.

[lynn comstock]

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.)

[edspace]

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.

[edspace]

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.

[lynn comstock]

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.