Painting Piping 1

[akcullin]

Hi,

I have a client who wants to stop painting all piping unless it's insulated (this is upstream oil and gas so outdoors). While this seems like a really bad idea to prevent corrosion, I can't actually produce a design code that says all carbon steel pipe must be painted.

Does anyone know if this is a code? I'm in Canada, though we design plant piping to ASME B31.3 and still use many of the American and API codes as rules of thumb, so any insight from any jurisdiction would be helpful.

Thanks.

 

[XL83NL]

A design code like ASME B31.3 will not prescribe such activitites (do a search in the B31.3 pdf on coat and you won't find any leads). Please keep in mind the B31 codes are not cook-book type codes that will dictate all activitites and steps required. It adresses only the minimum (safety) requirements. A lot of whats left is usually determined in the engineering design, often specified in the contract through e.g. (client) specifications, or additional codes or standards.

 

[LittleInch]

I can't actually produce a design code that says all carbon steel pipe must be painted.

That's because there isn't one. What there can be instead is either company standards and specifications or a corrosion study / material selection report which documents the issues, materials, types of corrosion and potential impact within certain time periods.

That's not to mention the appearance of said facilities and dealing with all the rust coloured streaks everywhere. Not to mention the claims and possible prosecutions for allowing such a situation to develop leading to leaks and ruptures.

If you're in any sort of location where you get condensation or rain / mist for anything more than a few days a year and basic carbon steel pipe will rust. How much it rusts is another question.

In dry desert locations, many flowline systems are not coated or painted and just laid on the surface or on rudimentary supports. Even there there are corrosion issues on the underside after several years.

Now sure, most "rust" is superficial or surface, especially if there is no pooling or constant wetness, but not painting or coating leads to corrosion defects.

So I would do a study which then recommends a substantial corrosion allowance and then see what the impact is. Almost certainly more than whatever is being saved from not painting the pipe....

Or you can look at Appendix F of B31.3 (Guidance and precautionary considerations), section 323. This doesn't limit corrosion to be internal or external.

"Consideration should be given to the use of cladding, lining, or other
protective materials to reduce the effects of corrosion,erosion, and abrasion.
(b) Information on material performance in corrosive environments can be found in publications such as Corrosion Data Survey — Metals Section, published by the National Association of Corrosion Engineers as report no. 37519."

"the susceptibility of the piping material to crevice corrosion under backing rings, in treaded joints, in socket welded joints, and in other stagnant, confined areas."







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[akcullin]

Thanks, very helpful reply.

 

[LittleInch]

No problem - just try and let us know what happens - even if it's in 3 months time - the posts normally stay open for up to 6 months before they close. Getting feed back and finding out what happened later is always very interesting to see if the advice worked or not!

good luck.

LI

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[BUGGAR]

I didn't look them up but I think both ANSI and OSHA have pipe paint color safety standards that may give guidance.

 

[moltenmetal]

It is common to not paint carbon steel structures in northern Alberta. It isn't warm enough long enough in the year to cause severe corrosion.

Paint on carbon steel pipe would be a similar situation. If the pipe has a substantial corrosion allowance, it may be acceptable to not paint it.

Most climates are NOT like northern Alberta, however. The right coating system for the Gulf coast in the US would be overkill for many other locations.

 

[urgross]

If you are inclined to paint pipe, it might be ANSI 13.1 you are looking for.