Shop fabrication of small bore piping

Hi Peter Pyper,
If you’ve been working in Calgary for a while, then the chances are that we know each other. Basically you’ve nailed it. Everything will be designed, modeled and iso’d down to NPS ½ for both stick built and modules by the EPC. The butt-welded and SW piping isometrics are issued to a spooling fabricator and spools are sent to the module assembler or, in the case of the stick built piping, to the field for erection. Threaded piping is still run in-situ by the module assembler or the field as the case may be. Maximum shop fabrication and module assembly is the goal. This is a departure from the more traditional shop-field split that has been followed up to now where NPS 2 and above (butt-welded) is shop spooled and SW and threaded is within the scope of the field or the module assembler, although iso’s have always been provided.

After speaking with a couple of other people around town, I have come to find out that, while not the norm necessarily, this isn’t totally uncommon. Interestingly for me, I have only encountered this approach once before in my career many, many years ago when I was a junior and I have no recollection of how well it worked or didn’t work on that project.

Regards,
Flowr8

H Jop,
I believe that some construction work packages have been issued with the small bore as shop fabricated, but I'm not sure how it's working out. I will check and get back to the forum.

It’s been a long time, but as promised I have feedback for you on the success of the shop fabrication of 1½” and below SW piping. The general consensus from fabrication and construction is that it is working out well, largely due to the fact that the use of 3D CAD for the modelling of these small bore lines produces a high degree of accuracy in the pipe routing.

The negatives are that the fabricators find it a challenge to move it through the shop efficiently due to fit-up time taking longer than welding time, so they have to schedule the small bore with some larger bore to balance the shop activity. No spool fabricator would outright say it, but inference is that if all they were sent were small bore piping orders they wouldn’t be too interested in the work, but provided they have lots of large bore butt weld spools to fabricate to go along with it, they’re happy to accommodate it.

Damage in shipping and handling is more likely than that of large bore spools and consequently there’s invariably some field repair required at site. To reduce this likelihood the maximum spool length that has been adopted is 20ft (6m) as opposed to the more common 40ft (12m) for large bore.

Overall though, it does save time in the field and has proven to be a worthwhile endeavor.

I am working on American projects since last 2 years. As per project specification all butt welded and socket welded material is to be marked as shop fab category. Only threaded material is marked as field category.
The spooling length for 2" and above pipe is 40'X8'X8' and for 1 1/2" and smaller pipe it is 20'X8'X8'.