Cold Spring

dxla-

I don't believe anybody but Code Committee members have seen the 2004 edition yet. It was in line to be published after the B&PV Codes were and those were just recently published. However... In my 2002 edition equation (22) in 319.5.1 includes a factor for cold springing.

However, simply being code legal doesn't make it good. I'd only accept a cold spring design when all other options have been exhausted. Having experience in the operating company world, I absolutely have to agree with Charles Becht IV's Process Piping: The Complete Guide to ASME B31.3 Second Edition in which he states (with regard to cold springing) that Its implementation in the field is generally difficult to achieve accurately. After the plant has been operated, deliberately installed cold spring can be misunderstood to be piping misalignment and "corrected."

jt

I have to disagree on the merits of cold spring and the statement that cold spring can be misunderstood as piping misalignment. I never seen a system where cold spring could be mistaken for anything else. I've never seen where the application of cold spring was any problem, granted it takes a little experience and undestanding, which is getting harder to find.

First of all I hope no one would jump in on any piping system and start correcting misalignment without a looking at a print and design conditions not matter what the process fluid.

I don't know the current industry thinking on cold spring, speaking specifically about steam lines, but all steam lines over 300 PSI that I've seen installed had a prescribed cold spring applied during installation by competent pipe/steam fitters. I’ve some of the older fitter foreman take out their little book and do a little sketching to check an engineers numbers. At our site the original steam lines installed in 1952 and have served the site well with no sign that they want get another 50 years service. The main 650 psig 750°F steam header has survived 9 severe excursions with only a small amount of insulation knocked off on the line side elbows on some expansion loops. Several of these excursions would have taken out any expansion joints.

We also design cold spring into hot gas lines if possible to eliminate the use of expansion joints.

Realizing that a more thorough analysis is possible with computers but a simple thermal analysis one can do wonders in determining where the pipe will land when operating. With a little judiciously applied cold spring alone with guides and supports gives one a good feeling to see a riser become plumb and elbow come to 90 degrees.