How to Touchup Compromised Galvanized Pipe?

8/21/2025

During on-site install (such as grooving, threading, and collisions during handling), its possible to damage the galvanized layer of the pipe.

How should we best address this?

Is spraying anti-corrosion paint on the damaged areas the best option? Something like a galvanize spray or are there other better treatment methods?

Thanks in advance.

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

3 Comments

Dan Wilder

8/21/2025 09:37:42 am

Any cutting, grooving, or welding activities will compromise the galvanic coating on pipe. You can push for hot-dipped over electroplating to help with a stronger coating and I would reach out to your local fabrication facility to discuss their process.

Luckily, in most cases, if you are using galvanized piping the protection is for the inside of the pipe where threading and cut grooving doesn't damage the coating. Now the cutting of pipe and roll-grooving will cause some spalling and cutting//welding will both expose untreated material and also burn the coating (when done incorrectly or not cleaned after the fact).

If the worry is the exterior, that can be addressed with cold-spray or paint the pipe.

The use of a galvanized cold spray, with the higher zinc content %, is the best end user post fabrication option (again, reach out to the fabricators in your area and ask what they are using or a nice can of Rust-Oleum is a good start). The more expensive path would be to fabricate everything, then apply the galvanized coating to all pieces (done at the fabricator).

Ryan Hinson

8/21/2025 09:46:34 am

For exterior locations such as deluge systems down on the Gulf and based on direct recommendations from corrosion experts such as ECS, I have had success with requiring two coats of acid etching primer over the compromised surface area which may include welds, exposed threads after make-on, wrench knicks, dings etc.

Where aesthetics are important, then painting/coating of the piping after installation may be appropriate. If this is the case, then proper pipe/fitting surface preparation prior to paint is important. I require surface preparation (roughening) IAW SSPC-SP 16 for proper coating adhesion. Paint will not maintain adherence well to unprepared galvanized surfaces.

Other options include:
- hot-dip galvanization of prefabbed spools IAW ASTM A153.
- two-part shop applied fusion-bond epoxy IAW NAPCA bulletin 12-78-94 per AWWA C210 or C213.
- Anticorrosion systems such as AWWA C209, C210, C213, C214, or C217 and repairs IAW mfgr recommendations.

In my experience, cold galv (zinc) spray may not hold up well and is too easy to substitute gray paint for the real thing.

Ideally, I require acid-etching application, surface prep, and final coatings.

Jack G

8/21/2025 11:46:33 am

If it’s for exterior - threads, damaged areas— I clean, put galv primer, then cold galvanising.
If it’s the inside/ underside of roll groove — I clean, use acid etch, then apply galvanizing.
Then flush system before putting it in service.

Leave a Reply.

Home
Our Cause

The Blog
The Forum

PE Exam Prep
The Toolkit
MeyerFire University

Pricing
Login
Support
Contact Us

MeyerFire.com is a startup community built to help fire protection professionals shine.
Our goal is to improve fire protection practices worldwide. We promote the industry by creating helpful tools and resources, and by bringing together industry professionals to share their expertise.

MeyerFire, LLC is a NICET Recognized Training Provider and International Code Council Preferred Education Provider.
All text, images, and media Copyright © 2016-2025 MeyerFire, LLC

We respect your privacy and personal data. See our Privacy Policy and Terms of Service. The views, opinions, and information found on this site represent solely the author and do not represent the opinions of any other party, nor does the presented material assume responsibility for its use. Fire protection and life safety systems constitute a critical component for public health and safety and you should consult with a licensed professional for proper design and code adherence.

Discussions are solely for the purpose of peer review and the exchange of ideas. All comments are reviewed. Comments which do not contribute, are not relevant, are spam, or are disrespectful in nature may be removed. Information presented and opinions expressed should not be relied upon as a replacement for consulting services. Some (not all) outbound links on this website, such as Amazon links, are affiliate-based where we receive a small commission for orders placed elsewhere.

How to Touchup Compromised Galvanized Pipe?

Leave a Reply.

ALL-ACCESS

SUBSCRIBE

COMMUNITY

YOUR POST

PE EXAM

FILTERS

ARCHIVES

PE PREP SERIES