hot dipped galvanized bolting under insulation for pipe flanges?

[MARKPHARIS]

I have hot dipped galvanized bolting specified for pipe flanges that will be insulated. They have heat tracing and operate between 40-60. Is this ok to do.

 

[dik]

Make sure your insulation is 'draining', you don't want to trap moisture.

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

-Dik

 

[EdStainless]

The insulation and covers can be problematic at flanges.
Make sure that these are well installed.
The Zn will hold up well if protected and dry.
It is good to add to your piping inspection to check for rust bleeding from the drain holes at flanges.
It either means that your flange seal is leaking, or you have gotten water into the flange.

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P.E. Metallurgy, consulting work welcomed

 

[SJones]

Answer: Yes

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

 

[0707]

If you have foam insulation be careful. "Corrosion under thermal insulation (CUI) can occurre in a low-temperature hot water (LTHW) system. Diissolved oxygen (DO) levels (>4 mg/L) can result in severe tuberculation and through pitting of thin-walled carbon steel piping. Leachate from the phenolic foam insulation subsequently contacted the galvanized surface, resulting in high corrosion rates of approximately 1 mm/year."

regards

 

[dik]

Thanks 707... didn't know that.

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

-Dik