Safety relief valve testing

Selection of Safety Relief Valve Testing Equipment... 

Figure 10-16 A safety relief valve test-stand for dynamic testing.

The Role of Mechanical Integrity in Chemical Process Safety 233 Safety Relief Valve Testing and Repair Procedures... 

Sanders, R. E. and Woolfolk, W. H., Process Safety Relief Valve Testing, Chemical Engineering Progress, Mar. 1984, pp. 60—64. 

Occasionally, there may be business pressures or maintenance scheduling problems that would encourage the delay of prooftesting of safety critical alarms and shutdown systems. Such situations can also delay of vessel inspections and safety relief valve testing. Some type of variance procedure or review policy should be defined to handle this occasional need. Such a policy ought to require the review of all of the inspection and test records on the specific equipment involved as well as an approval of the superintendent of the area. 

Safety Relief Valve Testing and Repair Procedures... 

After some years of testing SRVs with significant volumes of gas, Woolfolk presented Process Safety Relief Valve Testing [22] to the Loss Prevention Symposium of the American Institute of Chemical Engineers. The resulting published article generated a lot of interest he published an updated version for the Chemical Manufacturing Association in 1986 [23]. 

Selection of safety relief valve testing equipment... 

Safety relief valve testing and repair procedures... 

Sanders RE, Woolfolk WH. Process safety relief valve testing. Chem Eng Prog 1984 Mar 60-4. 

Note that in lieu of testing, Par (b) 2 and (b) 3 above allows the use of a capacity factor of 0.80 as a multiplier on the stamped capacity of the spring loaded safety relief valve (nozzle bpe). Some manufacturers test specific valve/rupture disk combinadons and determine the actual capacity factor for the combination, and then use this for the net capacity determination. See Figures 7-10, 7-11, 7-12, 7-13A and 7-13B. c. A rupture disk de ice may be installed on the outlet side of a spring loaded safety relief valve... 

Compensation Factors for Safety Relief Valves Between Atmospheric Test Temperature and Actual Operating Temperature [24]... 

Safety relief valves are normally tested in the shop, or even on the equipment at atmospheric temperature. The set tolerances on the valves as manufactured are established by die Code as discussed earlier. In order to recognize the difference between the test temperature and the actual operating temperature at actual relief, the corrections shown in Table 7-lA and 7-lB are applied. An increase in temperature above design causes a reduction in valve set pressure due to the effects of temperature on the spring and body. 

PPG Lake Charles was one of the first chemical plants to openly discuss problems that users experience by improperly specifying and testing safety relief valves. Expertise on new safety valves could be obtained from manufacturers sizing methods were documented by various designers and users, but no one published practical SRV testing and SRV corrosion problems. 

The American Society of Mechanical Engineers (ASME) understands the need for a sufficient volume of gas to properly test a safety relief valve. Until the ASME provides some well-defined guides, a concerned chemical plant may wish to develop its own criteria for... 

Figure 10-15 A cartoon of a safety relief valve being tested on a test-stand without sufficient volumetric flow rate.

Figure 10-18 A well-trained mechanic testing a safety relief valve just as it is received...

How Often Is Often Enough When Testing Safety Relief Valves ... 

Figure 10-19 A crane is lifting a recently tested and reconditioned safety relief valve...

Vendor shall furnish test certificates for all pressure vessels or the necessary tests shall be carried out by purchaser before acceptance. They shall be provided with standard safety relief valves. 

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