ASME PTC 25-2018 pdf download.Pressure Relief Devices.
3-1 ITEMS ON WHICH AGREEMENT SHALL BE REACHED The parties to the test shall reach agreement on the following items prior to conducting the test: (a) object of the test (b) parties to the test (c) test site (d) testing fluid reference condition at flow-rating pressure (e) methods of measurement, instrumentation, and equipment to be used (calibration of instruments shall be in accordance with subsection 3-7) (f) number, size, type, condition, source, set pressure, and expected relieving capacity of the device(s) to be tested (g) person who shall supervise the test (h) the written test procedure, which shall include the observations and readings to be taken and recorded to comply with the object or objectives of the test.
3-9.2 Pressure Tap Profile Comparison With no test device installed, conduct a flow test at an intermediate test pressure; see the following steps: Step 1. With the data from the flow test, calculate the average friction factor for the length ofpipe between taps A-B and C-D. Step 2. Using the Lapple and Levenspiel model of the adiabatic ideal-gas integration of the mechanical energy (or momentum) balance for adiabatic flow from an ideal nozzle on a large reservoir, through an equivalent length ofpipe, to a second large reservoir(orto the atmosphere), calculate the equivalent pipe length to tap A using the measured flow rate, the average friction factor from Step 1, and the measured pressure at tap A. Step 3. Subtract the actual pipe length from the test rig entrance to tap A from the equivalent pipe length from Step 2 to determine a nozzle equivalent length. Step 4. Repeat Steps 2 and 3 for taps B through D. Step 5. Calculate the average nozzle equivalent length using the four values determined above. This average nozzle equivalent length is used to compensate for the actual pressure loss up to the test rig entrance.
3-12 MEASUREMENT UNCERTAINTY A post-test uncertainty analysis shall be performed to determine that the limits of uncertainty of the final flow measurement specified in Section 1 were met. A pretest determination may be performed to determine that the limits ofuncertainty ofthe final flow measurement speci- fied in Section 1 can be met by the specified instrument andprocedures. Aguide forsuch determinationis givenin ASME PTC 19.1. These determinations shall be docu- mented by the laboratory and available for review.ASME PTC 25 pdf download.