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We are in search of codes governing welding of a 304 stainless air intake to a natural gas compressor. The intake connects the filters to the turbo charger and carries 15psi or less. The construction contractor and the design engineers are actually the same company and are trying to say that welding procedures are not required for this piping. They planned on stick welding but at this time we have them shut down on the work until we can aquire some proper info....however we can not find anything in available code books to support our opinions on this. We feel that TIG welding is needed to insure cleanliness. We also have piping installed on the compressor units by the vendor with no welding procedures established. What codes apply to all of this????
In most cases the design Eng. has the final say so on procedures & specifications but you being the customer have the final say so on excepting what is proposed.
API has some codes on rotating equipment but does not get in to any actual welding process.
You have the right to see the vendors PQR (Procedure Qualification Record) that demonstrates that the chosen proccess and materials will produce the desired results. A WPS must have a PQR to back it up unless it is a code pre qualified procedure.
Who is the manufacturer? I'd call them first especially if it is a Cat. Most pre turbo intakes are mild steel except for the flange that bolts to the turbo which can be 304, but in every instance we used sticks. Why bother doing an aircraft quality weld on something that isn't going to be x-rayed. Your main concern is clean surfaces and if they can produce that without GTAW then everything will be fine. Regardless of technique most most engineers require spin blasting (18"+) after the the tube is completed. This step is the worst because it leaves 3" of sand in the tube and dust that must be wiped out by hand with somebody wearing a respirator. Whatever the case may be take pictures right befor installation. Duct tape, a long stick and a camera with a timer. On the plus side you'd be amazed at what kind of stuff a big V8 Ajax can eat up. Sunglasses and a glove, plastic wrap and other things I've heard stories about. And these also have a constant vacuum or else I'd start runnung.
Back in my days of erector engineer, I was in charge of the construction of two natural gas compresssing stations in Argentina. They were located on the Neuquen to Buenos Aires natural gas pipeline and consisted of four 3,000 HP Solar Centaur gas turbine compressors (great machines!) and auxiliary equipment and buildings.
The client was Gas del Estado, the Argentine state gas company, now privatized, a very severe, although fair client.
All of the piping (design and erection) had to follow ANSI B.31 Code for Pressure Piping, Section 8: Natural Gas Transmission and Distribution Piping Systems. Nowadays ANSI B.31 has become ASME/ANSI, but the containt is the same.
Does that help you in any manner?
Giovanni S. Crisi
Sao Paulo - Brazil
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