Comercial Kitchen Exhaust Duct Material Selection
This is my first post. I am the job super for a new restaurant. My past experience is with residential construction. We hired a hood sub contractor that i am having great difficulty with. He is using plane carbon steel duct work to extract steam from a hood for a kettle to boil bagels in, and a hood for a dishwasher. i can't see this lasting too long. It is the same type of material that he used for the grease hoods. I would assume it is fine for grease hood ducts but to extract steam? I don't see this lasting very long. He insists its fine and he insists that because in his contract he did not specify that he was going to use stainless he does not have to give us stainless. We are governed by international mechanical code. Will this pass inspection? I read the code book and found code # 506.2 about corrosion. It states ducts exposed to outside atmosphere or subject to a corrosive environment shall be protected against corrosion in an approved manner. As far as I see it steam is a corrosive environment. He insists this code is only for outside duct work. Is he right? Are there any published standards or codes that say you can't use raw steel for this application? Any help would be appreciated .
What does the Mechanical P.E. Spec. book say about this? What's on the prints? Is there a fire suppression system on the hood? The code on that may tell you S.S. with Welded seams.
You need to check your LOCAL building codes. If you are in CA, SC, FL the code will probably require you to use Stainless Steel duck with welded seams. That code item you quoted does not only apply to Outdoor Air, a good inspector would probably apply it to the entire system.
You could the licensing agency for the building permit and get an answer, but be prepared for the results. It's like waking a sleeping lion.
Originally Posted by ALAN51
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as stated you need to check local codes, some do allow balck steel for the duct work to connect the stainless steel hood to the fan on the roof, welded seems, proper cleanout door access, clearances, etc.... both local city inspectors and fire department are usually involved in the permit and inspection process, but as was posted by other, if you get them involved it can open a can of worms and become your night mare....
I just raised a big stink over galvanized ductwork and Terminal units installed where there should have been Stainless steel. Even theatened to make a couple phone calls, it all going to be changed.