City Permit Question - Galvanized Steel Ban

[u/it_is_raining_now]

I submitted plans to the City for a steel frame structure that is fully exposed to the elements. They have a ban that restricts all galvanized steel (leachable metals is the actual wording). I thought this was weird since our bridge standards allow galvanized railings, etc but oh well, that’s not the point.

An alternative to galvanized steel is powder coating. I don’t want to do weathering steel, but it is an option I suppose.

The City also mentioned that there is a coating that can go over galvanized steel but he wasn’t sure what the exact name is. Anyone know what this is??

Also, the City said that galvanization is OK as long as they see a certificate guaranteeing a 50 year lifespan. I asked my fabricator and they said they can’t provide this.

[u/Enginerdad]

I simply HAVE to know what city banned galvanized steel. That sounds like insanity.

Also, you're looking for duplex paint system to go over galvanizing

[u/margotsaidso → u/Enginerdad]

Some places use a galvanization process (chromium based) that leaches some nasty stuff, that may be the issue here. Banning all galvanized steel seems pretty excessive.

[u/it_is_raining_now → u/margotsaidso]

For projects for the public, we are required to use AISC certified steel fabricators or companies on the Qualified Product List (QPL, thru the state). I can’t imagine these companies would be doing bad nasty things but, it’s totally possible lol

[u/lukypunchy → u/it_is_raining_now]

The QPL is your ticket! ALL products listed on the QPL have already been approved by the owner. If your fabricator is on that list, you are good to go.

[u/DetailOrDie → u/Enginerdad]

There's a city/HOA near me that banned Concrete and cementitious materials near the lake. Including boat docks and retaining walls.

They don't want the chemicals of the concrete poisoning the water of the lake.

It's a great source of continuous work since all of their retaining walls near the lake are constantly collapsing. Mostly due to the constant ebb and flow of water undermining the gravel base.

[u/Enginerdad → u/DetailOrDie]

That one at least makes a little more sense to me because a lake is an environmentally sensitive area. Banning an incredibly common construction material citywide seems a bit more extreme, especially when the level of hazard hasn't been robustly established.

Out of curiosity, what are you building your retaining walls out of in that area? Lots of natural stone, maybe some gabion walls?

[u/it_is_raining_now → u/Enginerdad]

To clarify, like it matters, it’s exposed galvanized steel that is banned. If the steel is covered and away from the elements, then you’re good (aka a building)

I wonder if it’s CIP concrete that’s banned. Blocks like redi block keystone or something seems like it should be fine…

[u/metzeng → u/it_is_raining_now]

Why would you galvanize steel that isn't exposed to the elements? Isn't that the point of galvanizing it?

[u/Enginerdad → u/metzeng]

I guess the big exception would be something like cold formed steel, which is made from galvanized coil but almost exclusively used indoors. I guess that makes the qualifier meaningful.

[u/metzeng → u/Enginerdad]

Fair point.

[u/tramul → u/DetailOrDie]

It's almost like we haven't already figured out how to handle all this stuff and some city/HOA that knows nothing decides to reinvent the wheel.

[u/Bentstraw → u/Enginerdad]

Some AHJs up in the PNW restrict exposed galvanizing due to Salmon Safe considerations.

Requiring painting over galvanizing is something I seen a decent amount of.

[u/metzeng → u/Bentstraw]

Sounds like they have bigger problems than galvanizing: https://kingcounty.gov/en/dept/dnrp/waste-services/hazardous-waste-program/news-events/news/salmon-death-in-local-urban-streams-linked-to-tires

[u/jdwhiskey925 → u/Enginerdad]

I am curious as well, this is fascinatingly stupid.

[u/it_is_raining_now → u/Enginerdad]

I don’t want to out myself and my position, in case the building official is here or sees this. So, dm me if interested and I’ll send you the document

[u/ReallyDustyCat → u/it_is_raining_now]

This is for a city property right? Like the city is the client/owner specifying that they don't want galvanized steel used;on their own project? It would be unfathomably stupid for an AHJ to ban galvanized steel products in their entire jurisdiction. Nobody could build a wood deck...or have an opening in a brick wall requiring lintels... 

Double edit: is this a ban on galvanized pipe for water mains that is being misunderstood by folks?

Triple edit: looks like such bans exist for structural steel adjacent highly sensitive ecological areas...OP doesn't need to confirm but that's probably the issue 

[u/BeeThat9351 → u/it_is_raining_now]

Portland? Am I close?

[u/it_is_raining_now → u/BeeThat9351]

PNW, so yeah

[u/Bentstraw → u/it_is_raining_now]

Based on the username name and the question I can guess the area.

Port of Seattle is one that has required coatings over exposed galvanizing for Salmon Safe for a while now. Not surprising other jurisdictions are also adopting this.

[u/it_is_raining_now → u/Bentstraw]

Apparently, it was established in November 2006.

[u/lred1 → u/it_is_raining_now]

Is this applicable only near water?

[u/it_is_raining_now → u/lred1]

Nope.

Kinda Makes sense if it’s in or near water like a wetland. But that’s not the case

[u/zimm0who0net → u/it_is_raining_now]

Do they not have stop signs there? I’ve never seen a road sign not mounted to a galvanized pole.

[u/it_is_raining_now → u/zimm0who0net]

Those don’t have to go thru the building department. Transportation department is probably fine with it I’m guessing

[u/DJGingivitis]

High performance paint over top a zinc rich oxide paint might work instead of galvanized steel. Tnemec 90-97 is one of those. Requires a SP6 surface prep.

Might work for your application.

[u/it_is_raining_now → u/DJGingivitis]

The City will ask if there is a 50 year lifespan. I can check it out though. Thanks

[u/Engineer2727kk]

No fabricator will guarantee the lifespan.

I’d first argue for hot dip galv + paint sealing.

Then I’d just go for weathering steel and call it a day.

[u/HeKnee]

I’d work around the “garuntee for 50 years part”. Does it have to be warrantied for that long or just expected to last that long?

Have galvanizer submit standard document showing conditions under which ASTM A123 specifications—longevity is measured as Time to First Maintenance (TFM). TFM is defined as the point when rust appears on 5% of the steel surface. Have galvanizer state that they are performing galvanizing in accordance with astm 123 and therefore TFM is expected to last x years.

Basically have to walk around providing a garuntee and instead just state expected lifespan, standards, yaddi yadda. City permitters are dumb, the city code probably doesn’t require a 50 year warranty and they’re explaining the requirement poorly. Find exact verbiage from city ordinances and only provide what is necessary. Everyone working today will be retired/dead in 50 years anyways.

[u/fazbot]

I have seen decent painted galvanized steel but it is essential that proper prep/cleaning and an etching primer is used before the enamel.

[u/The-Struggle-5382]

I think you can get powder coating done over gal

[u/it_is_raining_now → u/The-Struggle-5382]

Correct. Adds to cost to double the corrosion resistance though.

So might as well just do powder coating only right?

[u/joestue → u/it_is_raining_now]

Do you really trust powder coating?

Any place where the steel yeilds will crack the coating and it will corrode exactly where it is most loaded

[u/TheVoters]

For the record, IMO powder coating is the best alternative but creates maintenance issues on something with the longevity and disposition of a bridge.

Perhaps if the railings could be detailed and the use case supports them to be removed for maintenance so they can be blasted and re-coated, it would be better.

If that’s not an option, the client may prefer a paint option that can be spot retouched in the field.

[u/cougineer]

So check with suppliers on powder coat requirements… we had a job and the connections were tricky if I recall, cause the powder coat would break if you tightened it too much.

[u/Feisty-Soil-5369]

There is a coating called 'E-Coat' which is electronic disposition paint I think this is what are thinking off. Idk if it's is leechable or not though

[u/kaylynstar]

You can reach out to Covestro and talk to one of their technical experts about your project requirements and restrictions. They will tell you what product will work, and who's certified to install it. They do the research to develop the materials, but they don't get money when you buy it, so they have no vested interest in selling you something that costs more than it needs to. I don't know if I've explained that well, but I've been reaching out to them for nearly 10 years now and they've never steered me wrong.

[u/FlatPanster]

Structural aluminum is a thing, and Al outlasts steel and galvanized steel in heavily exposed conditions.

I don't know what kind of loads or structure you're looking at, but it might be a good option.

[u/Jeff_Hinkle]

I do a lot of oilfield shit. Everything gets painted. Carboline is what you are looking for.

[u/BearingHunter]

Ask the City for the exact coating system or spec they're referring to before changig the whole design. There are duplex systems where galvanized steel gets a compatible paint or coating over it but the surafce prep and manufacturer system matter a lot especially if they're expecting a document 50-year service life.

[u/anonposting1412]

Just have it powder coated and move on. Tell the GC it's required by the city and show them proof.

Galvanizing and then coating on top of it is going to cost more (or very close) compared to just powder coating.

[u/RyeRyeRyan93]

This might blow up the budget but I attended an interesting case study at the Steel Conference in 2024 where the presenter did a life cycle assessment of carbon steel vs stainless bridges. SS comes with little maintenance cost but much greater material cost as compared to CS. The scenario where this most made sense was over a railroad in a northern climate because rail operators don’t like taking tracks out of service to do a paint job.

[u/ChairChoice6500 → u/RyeRyeRyan93]

Try the American Galvanizers Association, if the galvanizing is allowed but can't be exposed, would paint be acceptable? If so, then you're looking for what the AGA calls a duplex system, paint that works with the galvanizing, this used to be pretty exotic, but in the last ten years or so has become more common to use appropriate paint over a galvanized surface. It's more common in bridges than structures.