let us take the case of api 610 (why? because nema sm23 load allowable is very unreasonable - very low value. same with api 617 since its nothing more than "1.85xnema"). notice something. the rules are complicated. first its ok to exceed the table range by a factor of 2. it doesnt stop there. even if you satisfy the table values, the nozzle load must still pass the interaction formula for the values to pass. and here's the kicker - say you pass the first reqt (not exceeding the 2X the allowable rules) but failed on the 2nd req't (interaction are not ok), the pump may still be found ok provided you satisfy condition 1 and 2 (and that's another story).
To use the ROT program of C2 requires the understanding of the above rules
(confusing ain't?) else just look for the failed and pass remarks in the
status column of the C2 report .
that's just for starter. ok let's have a look at your posting. My
undersatding what the api 610, 617 (same as nema practically) and 661 says
is a bit different from what you have stated so i would comment on this
later. lemme add 2 more commentary before closing.
1. observed the arrangement of the pump. notice the weakest link? if you do
then it would help in the understanding of the use of pipe dia as the basis
for the allowable load and moment. and this values has been a subject of
much debate in the past.
2. the latest rev of the api 610 (not incoporated in 617 dissapointingly) is
an improvement. now you can specify in your po whenever you buy a pump a
heavy duty base plate say a triple strenght. the result is you get a higher
allowable load ( 3x higher)at minimal added cost.
man, the piping designer in this case is literraly under the mercy of the pump mfr. this forum may be use to influence the api 610 rules hopefully.
-----Original Message-----
From: animesh_singh@ril.com [mailto:animesh_singh@ril.com]
Sent: 04 May, 2002 11:25 AM
To: PipingDesign@yahoogroups.com
Subject: [PipingDesign] Allowables in Stress
Hello friends, thanks for sharing your views .
My this query is related to Allowable Nozzle Loads in various equipments.
For certain equipment's like Pump, Compressors, Turbine ,Aircooler, Heater the Allowable Nozzle loads and Moments are given against Nozzles Nominal Bore, where as for equipments like Vessels, Column, Heat Exchangers, Drum the Allowable Nozzle loads and Moments are given against Nozzles Nominal Bore and Flange Rating.
Example: According to NEMA -SM23 quotes the allowable for nozzle
(individual and combined ) equivalent diameter only example for turbine it
is 3F+M<= 500Dr}
Similarly API 610 quotes the Nozzles Loads for given Diameter only.
My queries are
Regards
Animesh Singh .
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ Received on Wed May 08 07:51:00 2002
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