ASME PTC 25:2018 pdf free download – Pressure Relief Devices
(a) This Code provides instructions in Part II for flow capacity testing and in Part III for in-service and bench testing. Testing of reclosing and nonreclosing pressure relief devices is conducted under various inlet and outlet conditions using steam, gases, and liquids for which valid physical properties are known.
(b) The validity of tests shall be determined in accor- dance to the requirements of subsection 1-3.
In order to qualify as a valid code test, the total uncer- tainties of the test, as calculated by the procedures of ASME PTC 19.1, must be equal to or less than the values of maximum acceptable uncertainty. The maximum acceptable uncertainty of the final flow measurement shall not exceed ±2.0% of the measured value. For results other than flow measurements, the maximum acceptable uncertainty shall not exceed ±0.5% ofthe measuredvalue as determinedinaccordance withPartII or±1.0% ofthemeasuredvalueas determined in accordance with Part III.
(a) It is assumed that the testing facility has adequate capacity and sufficient pressure to conduct the tests. However, the users of this Code are cautioned that the capacity and pressure limitations of the testing facility may restrict the determination of satisfactory operating conditions and other operational features ofthe pressure relief device.
(b) In addition, field installation and/or abnormal operating conditions may adversely affect the function of the pressure relief device. It is not the intent of this Code to attempt to assess the suitability or reliability of the pressure relief device under such conditions. It should also be noted that if the temperature of the medium used to test the pressure relief device differs substantially from the temperature to which the pressure relief device is subjected while in service, the functional characteristics will be different from the test pressures, i.e., opening, closing, blowdown, and burstingpressure. In this case, it is necessary to develop appropriate correc- tions for the pressure relief device under test to account for these differences, which is outside the scope of this Code.
(c) This Code provides recommended test procedures and instrumentation for testing devices. Other testproce- dures or instrumentation may be used provided they can bedemonstratedashavingaccuracyandreliabilityatleast equal to the requirements of this Code. If another proce- dure or instrumentation will be used, it is subject to written agreement by the parties to the test prior to the test.
(d) The test results shall be reported as measured and calculated. Only tests that comply fully with the manda- toryrequirements ofthis Code maybe designated as tests conductedinaccordancewithASME PTC25.Referencesto other codes, unless otherwise indicated, refer to ASME Performance Test Codes. Should any specific direction in this Code, or any particular measurement, differ from those given in other ASME Performance Test Codes for similar measurements, the instructions of this Code shall prevail.
(e) The requirements of ASME PTC 1 shall be met.
(f) In some cases, the testing ofpressure reliefdevices may involve the use of high-pressure and high-tempera- ture fluid. Hazards to personnel will existunless adequate precautionary measures are taken. Special consideration should be given to adequate design and overpressure protection to the piping system and components, safe discharge from the pressure relief devices undergoing testing, and the high noise level usually associated with the discharge of pressure relief devices. The users ofthis Code should consult the authority having jurisdic- tion overthese safetymatters to ensure the testingfacility meets the mandatory requirements.