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Transfer of hydrocarbons via galvanized piping

As a safety engineer, numerous components are brought to our attention as suspect in various scenarios. The use of galvanized piping to convey hydrocarbons is generally known to be disallowed or at minimum, discouraged in the oil and gas industry. Most people are very aware of the dangers associated with the fumes from heated galvanized metals; however, no one seems to be able to say why, although everyone agrees that galvanized piping is not to be used for hydrocarbons. Please clear the air for us.

Thank you,

Doug Fontenot
EHS Field Coordinator - Lake Arthur, Louisiana, USA
2004

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As I recall, some years ago it was discovered that aluminum could react violently with certain organic solvents. I hope someone will clear the air too! Until they do, I 'll just have to guess that because zinc is likewise a very active metal, there is concern about the possibility of energetic reactions with unknown organic solvents

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003

Galvanized steel pipe is subject to hydrogen embrittlement. This is why hydrocarbons and not to be transferred. The steel can crack especially if under high pressure and temperature.

Tom Ward
coatings and chemicals - St. Pete Fl USA
2004

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Thanks, Tom, but I'm still confused!

Galvanized pipe is (obviously) steel pipe that has been galvanized. I don't know how hard steel pipe is supposed to be, but it's soft enough to readily thread.

Are you saying that steel pipe must not be used for hydrocarbons, because the steel (even though not hardened) is subject to hydrogen embrittlement? Or are you saying there is a possibility of the pipe having been hydrogen embrittled during the galvanization process, and this renders it unsafe for high pressure use? Thanks again.

Wait, I think I just got it. It's a high pressure application, so high strength pipe must be used, so you mustn't galvanize it for fear of hydrogen embrittlement.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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I THINK, MAYBE, ZINC WOULD DISSOLVE IN HYDROCARBONS AND MAYBE COMPOUNDING IN SOME TYPES OF ORGANOMETALLIC REACTIONS. BUT I AM NOT SURE AND NO SOLID REFERENCES ARE ON HAND

Khair Shishani
aircraft maintenance - Al Ain, UAE
2004