Metals which are resistant to Hydrochloric Acid (33%) & Caustic Soda 4

[ZeffireSprinklers]

Good Morning,

We have a Customer who has a existing Fire Sprinkler system protecting his premises. The factory produces Plastic Coated Freezer Baskets. Within the manufacturing process, the wire baskets are dipped in both 33% conc. hydrochloric acid and caustic soda (presumably as cleaning agents). Above the baths, the existing mild steel pipework is showing signs of corrosion as are the none ferrous (gunmetal / dzr) sprinkler heads (these are turning green, presumably verdigris due to dezinctification?). Would anyone be able to advise the optimum choice of material/s to resist this combination of chemical attack please?

Many thanks in anticipation of your assistance.

 

[EdStainless]

What does their insurance company suggest? After all, that is why there is a fire suppression system.
It sounds like they need a lot better air handling and ventilation.
I have seen epoxy coated stainless used for fire suppression piping in severe applications. You can get stainless heads as well. The only source that comes to mind is Victaulic, but suppose that all of the big players make them.

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[tomwalz]

Stainless is good but watch the welds. I had a stainless steel vessel corrode thoregh in the lab at the welds.

tom

Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

 

[unclesyd]

All hoods and ventilation systems exposed to HCl we have are RFG with fire retardant additives. At my last check the part of the exposed sprinkler piping Hastelloy C. I'll try to find out what the sprinkler heads are made of. The system is a charged system. Some structural steel and piping is coated with a high build Coal Tar Epoxy.

We wrap a lot of piping and steel with the products from Denso.

http://www.densona.com/index.htm

 

[kenvlach]

There should be a local exhaust at the hydrochloric acid tank, ducted to an acid scrubber (can use water from a flowing rinse tank). If large, GRP as mentioned by unclesyd is used; if small, PVC is commonly used.

Also, the general area ventilation needs upgrading. The sprinkler pipes may only be the [tip of the iceberg.' In many metal finishing plants, chemical vapors combine with water vapor condensing in the insulation on the roof underside, also attacking the superstructure, lighting & other electrical.