Well it appears I'm late but I have a couple of things to add...

First cold spring if performed properly on a system operating below the creep range is beneficial. How so you ask? It allows a quicker "shakedown" to occur.

However I agree with the previous replies centering on the phrase "if performed properly".

I am kind of an old guy and I remember well the heady days of punch cards and green bar paper. In those days we might "cold spring" once in a blue moon. The few times I resorted to this stress range, slight of hand I did so on systems where between the two end anchors there was a loop available.

The advantage was that you could pull back on the pipe end using a pair of sturdy guides that would be left in place to help keep things straight. The other advantage was that rotations of the ends was minimzed.

Did I think it worked then and what do I think about it now?

Back then I doubted that I would get everything I needed in load reduction so I always left some room (25% off either + or - on the springing) for construction vagaries.

What about now a days? I currently wouldn't bet a nickle for sucess in this type of enterprise. Recently a bone head constructor decided that the tie bars I had specified for a set of Exp Jts were superfluos without asking me my opinion. Fortuanately they were going to hydro the steam system that the Exp Jts were in and nobody got hurt, when they became hyperextended. So if they ignore specifications written in english about what Exp Jt to buy what do you think your chances are? (See the pictures below of the ExpJts after the hydro.)



So there you go, if you do take the cold spring route design the system to make springing the ends together easier (reduce rotation reactions as much as possible). If you try it and succeed email me I would like your assistance in picking some lottery numbers!

------------------
Best Regards,

John C. Luf



[This message has been edited by John C. Luf (edited August 09, 2000).]