ISO standards and regultations

Rules and regulations, standards and specifications

Anne Cunningham - 23 April 2015

Does the failing of austenitic SS bolts in valves warrant a new set of standards?

About the author

Ms Anne Cunningham
Anne Cunningham is a freelance member of Valve World magazine's editorial team and owner of Cunningham Text & Translation where she works as a text writer, (online) news editor and translator. Raised bilingual, she is experienced in writing about the process industries in both English and Dutch.
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Within the editorial team of Valve World, one of my jobs is to make sure that the news goes online. This means I get to read all news concerning the valve industry, but also all related industries. Reading all these articles I can’t help but notice similarities. Not in writing style or in use of words as you might expect from an editor, but in themes. And there is one theme that keeps popping up everywhere I look: rules and regulations, standards and specifications.

Each and every industry seems to be making, creating, and implementing new guidelines. There is no room for failure, no room for mistakes. Often completely understandable rules, sometimes maybe not so much, but one thing is for sure: all industries are affected, including the valve industry. Every valve produced has to meet the standards for the industry it will be used in and no company can afford to fall behind. ISO’s are being achieved and tests and accreditation are being passed and granted all over the world.

In March last year Valve World featured Failed austenitic SS bolts in valves by Kristian Lund Jepsen and Per Grumsen from Ramboll Oil & Gas. They wrote the article because they noticed a rise in the number of cases with valves in offshore environments in which the internal bolting in austenitic stainless steel failed after some time in that environment. After looking into it they realized that most often it concerned valves operating in temperatures of 50–60˚C or more, and the failure mechanism being chloride-induced stress corrosion cracking in austenitic bolts.

In their article, Kristian and Per strongly recommended operators of offshore oil/gas installations to investigate if they have valves with austenitic stainless steel bolts in service conditions with temperatures above 50˚C on their installations and replace such valves or at least the bolts. For stainless steel valves, super duplex stainless steel bolts were mentioned as a good alternative.

Looking back at the theme, should this mean the piping and valve specifications must be changed in order to void purchasing valves with austenitic stainless steel bolts? According to the authors, definitely and I have to admit that when reading about a two-piece 2” ball valve on a fuel gas skid, in which all four internal bolts keeping the two parts together failed, I tend to agree. The failure resulted in the release of almost 500 kg (= 500 m3 at atmospheric pressure) of natural gas during a 3 minute release. Fortunately no ignition of the gas took place, but it is once again an example of the necessity of all these rules and regulations. An ongoing process and as innovations take place, new regulations will emerge...for a reason.

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