Hello,
Regarding the subject, I would like to ask opinions of Stress analysis and Support experts.
Situation is that I have a project that the spring supports(both variable, and constant) are set at cold load base, so that at non-operating condition piping can be aligned.
After review I sent information to design supports to vendor and mentioned that spring setting was 'cold balance', and I mentioned that to calculate the load variability, equation shall be [(cold load-hot load)/cold load].
In return, they did not agree the equation and insist that we have to use hot load to divide since per MSS-SP58 par.7.7.1.2 equation 1, operating load is 'hot load'. Also they mentioned that they never received such request from other customer such as 'big company'. Also they said that they have been doing this for a long time, and there weren't any problem with spring, but I think that does not mean it is correct way.
I try to find solid reference, though this topic has been discussed on this forum several times I couldn't find one.
Most vendors put equation for load variability only for hot load setting(For eg,
http://www.pipingtech.com/faq/article.php?id=147 , PTP mentioned that "hot” or operating load), but at this forum and
CAESAR II's user guide says that 'load variation is the ratio of the change in load divided by operating load' so if the user set 'cold load design', operating load shall be 'cold load'. (refer to
http://65.57.255.42/ubbthreads/ubbthread...=true#Post55896 ,
http://65.57.255.42/ubbthreads/ubbthread...=true#Post40668)
I think this causes argues and wrong design, since load variation can be different from what load we used for dividing. Somehow support types and size could be changed by this, and this could be fatal for some piping connected to compressor or rotating machine.
Would you kindly solve my query?
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