I'm new to this forum but have forty one years experience in the oil refining industry. I recently retired from a large independent refiner. At the time of my retirement, my employer consider it necessary to install fire case PSV's on both the shell and tube side of heat exchangers. I'm am doing some consulting work post retirement and have discovered that a couple of major integrated oil companies do not feel it is necessary to provide fire case PSV's on shell and tube heat exchangers. My question is what is considered RAGAGEP for fire protection on heat exchangers? My apologies if this has been discussed previously but I did not see a way to search past threads.
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Ragagep For Fire Case Protection On Shell And Tube Heat Exchanger
#1
Posted 01 December 2016 - 08:28 PM
#2
Posted 01 December 2016 - 09:25 PM
Hi ,
Let you try the search feature in this forum .
Good luck
Breizh
#3
Posted 01 December 2016 - 10:36 PM
What is RAGAGEP? I've worked as a process engineer for both operating companies and major engineering companies. And delivered projects for most of the major refiners, integrated and independent. Never have I seen, or specified a relief device on either the shell or tubeside of a heat exchanger required solely for overpressure protection by fire. Maybe your employer has some unusual requirements; maybe from insurers.
Bobby
#4
Posted 02 December 2016 - 04:29 AM
RAGAGEP is the requirement of ASME code for protection of all pressure vessels against over pressure regardless of whether there is any credible scenario of OP.
Then if the HX is in a fire zone and there is no other credible scenarios, the PSV fire case should be installed on the shell.
Also it might another PSV fire case being installed for tube side protection against OP of fire case.
#5
Posted 02 December 2016 - 07:43 AM
RAGAGEP stands for Recognized And Generally Accepted Good Engineering Practice.
#6
Posted 02 December 2016 - 09:35 AM
What is RAGAGEP? I've worked as a process engineer for both operating companies and major engineering companies. And delivered projects for most of the major refiners, integrated and independent. Never have I seen, or specified a relief device on either the shell or tubeside of a heat exchanger required solely for overpressure protection by fire. Maybe your employer has some unusual requirements; maybe from insurers.
Bobby
I talked to friends at two major engineering companies and in both cases their companies currently consider installing fire case PSV's on heat exchangers to be Recognized And Generally Accepted Good Engineering Practice. Practices have evolved over the years. Installing fire case PSV's was not always the case.
The shell and channel of a heat exchanger are designed by pressure vessel codes. Therefore my former company and the engineering firms I talked to consider both the channel and shell to be pressure vessels. It's pretty clear in API recommended practices that pressure vessels require fire case overpressure protection. This might be a PSV or it might be a guaranteed open path to another vessel with a large enough PSV. The rationales I have heard for not installing PSV's is that a shell and tube heat exchanger will self relieve in a fire or there are lots of open paths the expanding vapor or liquid will go somewhere. Neither of these seem to fit the letter or spirit of ASME code or API recommended practices. I can buy a guaranteed open path as a reason for not installing a PSV. But that also entails making sure the pressure drop in intervening piping and equipment is low enough to keep piece of equipment without a PSV protected.
#8
Posted 02 December 2016 - 11:18 AM
Thanks sanderson231, that's interesting.
I've worked for 3 chemical companies during my 37 years. The process we used for NOT putting a relief device on the shell or tube side of an exchanger was so very onerous, that most engineers could think of at least one credible scenario to size one and put it on. That was usually fire case with vapor only venting. I think we are pretty much in compliance with RAGAGEP.
#9
Posted 23 December 2016 - 11:04 AM
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