As you know, max temperature for the usage of reinforcing pad is 300 in EN 13480 design code.

I have a doubt, whether is there any restriction for the trunnion supports. Can we weld trunnion with reinforcing pad onto pipe which has a 420C design temperature.

Regards

Any ideas?

To my knowledge there is no restriction for the trunnion pipe support as long as you can maintain the operation temperature in the trunnion as well against the thermal gradients and accelerated corrosion. But mostly this is not possible and not economical either. If the reinforcing pad is in the system the thermal gradient and resultant stresses may not be handled properly if we ignore the corrosion issue. If the system is cyclic the condition is worsen with reinforcing pad and trunnion itself.

I ignored the SIF in this discussion to cut shorter.

Therefore codes are resticting the use of reinforcing pads after certain operating/design temperatures.

So I would not try to use the reinforcing pad at this temperature. If you can change the location/type of the support(s)to eliminate the consequence.

I would suggest to use non-integral/clamp type supports at high temperatures to eliminate secondary stresses mainly sourced by integral supports. They can be above the code limitation in most cases at high temperatures. Additionally, be aware that the latest version of EN 13480 has a lot of mistakes if you want to calculate the secondary stresses and combinations. Please read the following:

http://www.eng-tips.com/viewthread.cfm?qid=306656

Good luck.

Ibrahim Demir