PRV Set Point Accuracy

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References The American Society of Mechanical Engineers (ASME) Pressure Relief Devices Performance Test Code 25-2001 25 2001 (PTC 25-2001) 25 2001) The National Board Inspection Code (NBIC) Plant testimonials – A special thanks to J. Alton Cox (Vice Chairman, NBIC Sub-Group Sub Group Pressure Relief Devices) for his contributions in guidance, and experience.
Definitions Definitions NOTE: For the purpose of this paper we are going to define the following as: High Volume test bench – PRV Test device with at a minimum capacity volume of 28 Liter [1 [ 1 cubic foot] test vessel and a minimum piping (between the Test Vessel Vessel and the Test Connection for the Valve being tested) diameter of 5 cm [2 inches]. Low Volume test bench – PRV Test device with a test vessel less than 28 Liter [1 cubic feet] and a piping diameter (between the Test Vessel and the Test Connection Connection for the Valve being tested) of less than 5 cm [2 inches]. Set Pressure – The value of increasing inlet static pressure at which a pressure pressure relief device displays one of the operational characteristics as defined under opening pressure, popping pressure, start-to start to-leak leak pressure, burst pressure, or breaking pressure. (The applicable applicable operating characteristic for a specific device design is specified by the device manufacturer.) PTC 25-2001 25 2001 Opening Pressure – The value of increasing inlet static pressure of a PRV at which there is a measurable lift, or at which the discharge becomes continuous as determined by seeing, feeling, or hearing. (For liquid Service) PTC 25-2001 25 2001 Popping Pressure – The value of increasing inlet static pressure at which the disk moves in the opening direction at a faster rate as compared with corresponding corresponding movement at higher or lower pressures. PTC 25-2001 25 2001 Start-to Start to-Leak Leak Pressure – The value of increasing inlet static pressure at which the first first bubble occurs when a PRV is tested by means of air under a specified water water seal on the outlet. PTC 25- 25 2001 Chatter – abnormal rapid reciprocating motion of movable parts of a pressure pressure relief valve in which the disk contacts the seat. PTC 25-2001 25 2001 First Steady Stream – Set pressure for liquid Service Pressure Relief Valves. When gravity gravity overcomes cohesion the water drops straight off the Pressure Relief Relief Valve outlet; an observable, repeatable Phenomenon. NB 18 Cohesion – the attraction of like molecules Note: For the purposes of this paper Test Bench, Test Device, Test Test Stand, and/or Test Unit are interchangeable.
Page 1: PRV Set Point Accuracy ASME NRC Pum
Page 5 and 6: Purpose To discuss some of the dif
Page 7 and 8: Internal Contours of Fittings, Adap
Page 9 and 10: PTC 25-2001 25 2001 Recommended Arr
Page 11 and 12: Test Plate Sharp Corner Air Flow Sh
Page 13 and 14: Recommended Volume Capacity Test v
Page 15 and 16: Recommended Volume Capacity Liquid
Page 17 and 18: Recommended Volume Capacity Testim
Page 19 and 20: PRV Seat Alignment Alton Cox (NBIC
Page 21 and 22: Liquid Test - Trapped Air in PRV No
Page 23 and 24: Method 3: Air Evacuation Incorpora
Page 25 and 26: Conclusion The National Board Insp
Page 27 and 28: Questions

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