I have taken over a job that is over half way through and the company has ordered a raft of API610 centrifugal pumps of various sizes for an upgrade project from one vendor.  As an additional requirement to API610, the company has asked for the seal chamber pressure to be meaured and recorded on test (mostly tandem seals used).  Nobody at the company or the pump supplier can give a solid reason why this should definately be carried out and why it has been asked for.  For some of the pumps, the vendor states there is no practical way to do this on test.  What do the experts think please?  Should I waive the requirement where the vendor thinks it is too difficult to do?  The pumps range in size from small up to about 750kW and various discharge pressures upto about 60 bar.

I like to document the seal chamber pressure when possible.  For centrifugal pump, you often see people use a "rule-of-thumb" to estimate seal chamber pressure.  But, depending on the configuration of the wear rings and balance holes, there can be quite a lot of variation. If you plan to use API plan 52, it may not be critical. But, if there is any chance that any of these pumps might end up with Plan 32, 53 or a gas seal, then this pressure is key.  I don't understand how any manufacturer of an API pump could claim that this is difficult. They have to provide the option to inject seal flush into the seal chamber.  All you have to do is connect a pressure gauge to an unused seal flush connection and monitor the pressure during the test run.  If the purchaser does not allow for unused process connections, then they have to make a decision.  Either allow a seal flush port with a plug or blind flange or skip the seal chamber pressure test.  If the pump does not have a connection suitable to monitor chamber pressure, it is likely that the seal gland does. 

I agree with NGLENGR however if you are using Plan 53B on your pumps chamber pressure is not relevant to seal performance.  The only relevance relates to determining the Pre-Charge pressure in the accumulator (Plan53B)  Review the P&ID carefully ensuring the Check valve is upstream of the accumulator as I have seen a bad design resulting in overpressurization due to heat expansion and no relief.  Also check that the seals can be properly vented.  Check the tubing size and ensure it is 3/4" with sweeping bends not elbows.  

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