ASME PTC-25-2014 pdf download

ASME PTC-25-2014 pdf download.Pressure Relief Devices.
1-1 OBJECT The object of the test is to determine the performance of pressure relief devices. These tests determine one or more of the following: (a) dimensional, operational, and mechanical characteristics (b) relieving pressure (c) relieving flow capacity at test pressure (d) individual flow resistance Procedures for conducting the tests, calculating the results, and making corrections are defined. 1-2 SCOPE (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 reliefdevices 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. 1-3 MEASUREMENT UNCERTAINTY 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 notexceed ±2.0% ofthe measured value. For results otherthanflow measurements,the maximumacceptable uncertainty shall not exceed ±0.5% of the measured value as determined in accordance with Part II or ±1.0% ofthe measured value as determined in accordance with Part III. 1 1-4 GENERAL (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 substantiallyfromthetemperature to whichthe pressure relief device is subjected while in service, the functional characteristics will be different from the test pressures, i.e., opening, closing, blowdown, and bursting pressure. Inthis case, itis 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 test pro- cedures or instrumentation may be used provided they can be demonstrated as having accuracy and reliability at least equal to the requirements ofthis Code. If another procedure 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- tory requirements of this Code may be designated as tests conducted inaccordance withASME PTC 25. Refer- ences to 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, General Instructions, shall be met. (f) In some cases, the testing of pressure relief devices may involve the use of high-pressure and high-temperature fluid. Hazards to personnel will exist 2 unless adequate precautionary measures are taken. Spe- cial 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 of this Code should consult the authority having jurisdiction over these safety matters to ensure the testing facility meets the mandatory requirements.