Steel coating for harsh environment

I am working on a PEMB that will be in a very harsh chemical environment. We are considering galvanizing, but we would like to consider some other options. Does anyone know of any other coating that might hold up to this type of environment. I'm concerned about the primary members, but I think the secondary members will be the bigger challenge. Any thoughts?

 

[WesternJeb]

Providing stainless steel members is typically what we do in harsh chemical environments. Make sure you look into each specific grade of stainless steel though, as each grade is reactive with different chemicals.

 

[ntattose]

Thanks for the response. Can you get SS purlins and girts?

 

[CrabbyT]

I worked at a chemical plant and used hot dip galv in most areas. Stainless steel is problematic because it's weaker and like 7x more expensive.

 

[dik]

It depends on the environment... with chloride environments, even stainless may not be suitable. Same with HDG... you should contact a coating supplier to see what is recommended... there are some excellent coating systems that are good for almost everything... but, they can be pricey.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[GC_Hopi]

Here is a lead if you are in the states. Link All you need is big enough pocketbook and the right vendor, manufacturer, contractor, installer that want to play.

 

[JStephen]

If you are not the manufacturer, contact the manufacturer to see what their options are. No point in specifying something if nobody can do it.
They do make some fiberglass structural products as well.

 

[XR250]

Use a wood building?

 

[canwesteng]

Secondary member can easily be HDG as they are gage metal cold formed sections. Harder to do with the large girders/columns. Stainless would cost a fortune. If you truly are in a case where a stainless building is warranted, a PEMB is unlikely to be the right choice

 

[SWComposites]

Maybe coat with this:

https://por15.com/

?

 

[Brad805]

Depends on the exposure. We rebuilt a 30yr old PEMB that has been exposed to aggressive chemicals for the past 15yrs. We sent the chemical specs to a company that specializes in that type of work and they recommended an epoxy product.

 

[dik]

It really depends on what you are protecting against... stainless or HDG may be totally inappropriate. I have about 20 or so coating systems to be use for different levels of protection against various chemicals... Find out what the chemical is and talk to a supplier.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[JedClampett]

I'd say that a two-coat epoxy and topcoat of polyurethane is probably as good as you need. Something exotic will be a lot more expensive and the chemicals will just migrate to nooks and crannies and still damage the steel.
Rant: As canwesteng said, you might want to rethink the use of a PEMB. I've seen ones that are trashed due to moist environments and aggressive sewage gasses. Even in ideal conditions they're made of thin members that are prone to corrosion with a bunch of gathering places for condensation. There's a zillion bolt holes and places for corrosion to start. If the client understands that the building will be unusable after _____ years (fill in the blank, 20, 25 30...), then you're off the hook, but that seems sleazy ("we told you it was a throw away").

 

[ntattose]

Thanks for all of the good responses. After looking into this a bit, I think the chemical that's causing the problem is ammonia, but I will need to verify. Has anyone heard of ammonia exposure causing this? I have looked into HDG steel and SS as a fix, but I am seeing some conflicting information regarding both. Has anyone had any experience with HDG or SS exposed to ammonia?

 

[CANPRO]

It is probably worth engaging a specialist or discussing with the coating supplier to address your specific concerns about the ammonia.

Rather than use a single protective system, you might want to consider a duplex system which can greatly increase the service life of your coating system. Here is a link for a brief description: [URL unfurl="true"]https://galvanizeit.org/corrosion/corrosion-protection/duplex-systems[/url]

 

[wrantler]

I would reach out to an coating specialist consultant. They do exist in my area. I tend to try and partner with these folks rather than try and 'do it myself'. I have a longish career ahead of me so have something to lose if my off the cuff ideas are not working.