ANSI Flange Pressure Ratings
ANSI Flange Pressure Ratings
(OP)
ANSI B16.5 furnishes information on Pressure / Temperature ratings of flanges. The pressures given are for NON-SHOCK values.
I have a pipe run (approx. 400 metres long) that occassionally experiences "hammering" due to rapid closing of a valve.
Would appreciate if anyone can tell how I can obtain / determine the maximum shock pressure values for the 150# A182 SUS 304 Slip On flanges operating at 40 deg.C
I have a pipe run (approx. 400 metres long) that occassionally experiences "hammering" due to rapid closing of a valve.
Would appreciate if anyone can tell how I can obtain / determine the maximum shock pressure values for the 150# A182 SUS 304 Slip On flanges operating at 40 deg.C





RE: ANSI Flange Pressure Ratings
[i.e., http://www.parker.com/frameless/default.asp?substDivId=&FamID=763&DivID=75&GID=0&Type=2&ID=75&TechID=&PSID=286 ]
RE: ANSI Flange Pressure Ratings
can you slow the valve down? its better to fix the source of the problem.
RE: ANSI Flange Pressure Ratings
RE: ANSI Flange Pressure Ratings
an accumulator will be the easiest fix.
ER
RE: ANSI Flange Pressure Ratings
Why add more equipment to the system with an accumulator?
RE: ANSI Flange Pressure Ratings
Art Montemayor
Spring, TX
RE: ANSI Flange Pressure Ratings
Dynamic loads will also affect the welds and bolts.
As all the previous postings suggested the proper way to deal with this issue is to solve the root cause, i.e. the hammering.
Also to consider is that as the standards provide values for non-shock pressures... liability and insurance start playing a rol because if anything happens the ruling would be that the equipment was operated outside the allowable range of operation... and may be construed as negligence.
HTH
saludos.
a.
RE: ANSI Flange Pressure Ratings
Thanks for the comments and advice.
We are considering following steps viz.
1. Stop the pump at the same time the valve is to be shut.
The timing of stopping needs to be fine tuned as the
pipe run is rather long. This should prevent hammering.
2. The shut off valve is "air to open" and in the event
of air failure, the valve will shut automatically
with the accompanying hammering. To address this
"failure mode" a relief valve will be installed
near the shut off valve so that any surge pressure will
be relieved and this should "damp" down the hammering.
We were thinking of setting the relief pressure for the
relief valve to be as high as the system design allows;
hence this query about the non-shock maximum allowable
pressure for the flanges which is the structurally
weakest link. Leakage through the gaskets as "abeltio"
mentioned is another concern which has to be addressed.
The other alternative is to install an accumulator or pulsation damper as "arto" suggested.
Incidentally, the main pipe run is 12 inch. stepping down to 10 inch then 8 inch at the flow totaliser before going into ships vide a marine loading arm. Shut off valve is downstream of the totaliser (before the loading arm).
RE: ANSI Flange Pressure Ratings
http://www.mokveld.com/
for info.
The problem is that the RV maybe wont respond quickly enough.
Best regards
Morten
RE: ANSI Flange Pressure Ratings
RE: ANSI Flange Pressure Ratings
Morten is absolutely correct. There is no such beast as a "quick acting type" of RV (relief valve). You'll still be waiting for the RV to actuate long after any hammering has leveled your long piping run.
I hope you never experience or witness the violent results of a shattered piping installation. I have, and it's a bitter price to pay. Good luck and safe operations.
Art Montemayor
Spring, TX
RE: ANSI Flange Pressure Ratings