Accostic Fatique in Relief System Piping

Please explain more. This might be a salient issue, but not yet very well known.

Eliminate the cause of the vibration.

http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V4C-481MTST-R2&_user=10&_origUdi=B6V35-47XG30B-DF&_fmt=high&_coverDate=12%2F31%2F1992&_rdoc=1&_orig=article&_origin=article&_zone=related_art&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=a001b89b3f030af6a8b8e0f42c62b364

Looks like it is $31.50 for a downloadable pdf.

Perhaps this might help.

If relief piping is undersized, fluid velocity can exceed the speed of sound. This could set up standing waves and such phenomena that might make for sonic-frequency vibrations, leading to early fatigue (note the g, not q) from the rapid accumulation of cycles. (This is a bit of a guess, suggested by "acoustic", but it may be what we're talking about.) Solution: larger piping. There was an ASHRAE (American Society of Heating, Refrigeration, and Air-conditioning Engineers) code revision in 1994 about this.

Acoustic fatique or vibration induced fatique are two different things. Acoustic fatique may be for the people working nearby and vibration induced fatigue is for the life of the relief system piping.

Acoustic fatique can be tackled by providing noise abatement measures in relief system piping. This can be done in following ways depending on severity of the noice:

1. Put a sound barrier (intall noice hoods).

2. Provide a silencer in relief system piping. It can reactive type or absorptive type or a combination of both depending on severity of the noice.

3. Provide mineral wool insulation of the piping.

It is advisable to check the noise level. Normally acceptable norm is 85 dB at one metre distance.

vibration induced fatigue can be tackled by providing appropriate piping support and reducing outlet velocity by increasing pipe size.

My concern is about the failure due to the vibration induced by sound in a relief piping system when the relief valve pop off

And how the D/t ratio, where D in inside dia and t is thickness of pipe, have an effect on acoustic fatigue. and what shall be the value for this.