Pressure Test-22.pdf

3 designations. 3.8 shell test A pressure test in excess of the cold working pressure (CWP) rating of the valve for the purpose of validating the soundness and strength of the valve pre...

3 designations. 3.8 shell test A pressure test in excess of the cold working pressure (CWP) rating of the valve for the purpose of validating the soundness and strength of the valve pressure-containing structures. 3.9 visually detectable leakage Leakage during a valve pressure test, either through or past a pressure boundary or closure member that is validated by normal vision. 4 Inspection, Examination, and Supplementary Examination 4.1 Inspection at the Valve Manufacturer’s Plant The purchaser shall specify in the purchase order intention to inspect valves and witness tests and examinations to any part of the plant concerned with manufacture of the valves whenever work on the order is under way. Witnessing may be performed by remote means (video). 4.2 Inspection Outside the Valve Manufacturer’s Plant manufactured at locations other than the valve manufacturer’s plant, these parts and components shall be subject to the valve purchaser’s inspection at the location where they are manufactured. Witnessing may be performed by remote means (video). 4.3 Inspection Notice stated in the purchase order or as mutually agreed with the purchaser. 4.4 Extent of Inspection to the following: c) witnessing of any supplementary examinations (see 4.6); 4.5 Examination 4.5.1 A visual examination shall be performed by the valve manufacturer on all castings of bodies, bonnets, covers, and closure elements to ensure conformance with MSS SP-55. 4.5.2 Each valve shall be examined to ensure compliance with this standard, purchase order requirements, and the referenced product standard (e.g., API Standard 599). 4 4.5.3 All examinations shall be performed in accordance with written procedures that comply with the applicable standards. 4.6 Supplementary Examination shall be in accordance with ASME B16.34 or with the purchaser’s own procedures and acceptance criteria, if so 5 Pressure Tests 5.1 Test Location Pressure tests shall be performed by the valve manufacturer at the valve manufacturer’s plant or at a facility mutually agreeable to both the manufacturer and purchaser. 5.2 Test Equipment 5.3 Tests Required 5.3.1 The pressure tests listed in Table 1 shall be performed on each valve in accordance with written procedures that comply with this standard.  5 Table 1—Pressure Tests Valve Type Test ASME Globe and Size Cat. Ah Floating Cat. Bh and Description class Gate Parallel Plug and Ball Trunnion Slide Gate Check Mounted Ball Shell All All Required Required Required Required Required Required Backseat a All All Required Required NA NA NA NA DN (NPS) Required Required f Required 1500 (NPS 4) Class > Low- Optional b Optional b Optional b 1500 pressure Optional b Optional b Required closure DN (NPS) Required Required f Required 600 > DN 100 (NPS 4) Class > Optional b Optional b Optional b 600 Optional DN (NPS) Optional b e Optional b e 1500 b e f (NPS 4) Class > High- Required Required Required 1500 Optional pressure Required d Required b e closure c g Optional DN (NPS) Optional b e Optional b e 600 b e f > DN 100 (NPS 4) Class > Required Required Required 600 NA Not applicable a The backseat test is required for all valves that have the backseat feature, except for bellows seal valves. b c The high-pressure closure test of resilient-seated valves may degrade subsequent sealing performance in low-pressure service. d For power-operated and manually-operated gear-actuated globe valves, including nonreturn-type globe valves, the high-pressure e f For lubricated plug valves, the high-pressure closure test is mandatory and the low-pressure closure test is optional. g In the case where both high- and low-pressure closure testing is to be performed, refer to 6.4.6. h 5.3.2 At the manufacturer’s option, the backseat test for valves that have the backseat feature may be either a high-pressure or low-pressure test unless stated otherwise in the purchase order. 5.4 High-pressure Closure Test The high-pressure closure test is required for several valve types, as shown in Table 1. For the valve types for which the high-pressure closure test is optional (according to Table 1), the valves are still required to be able to valve design to pass the high-pressure closure test shall be supplied when requested in the purchase order (see Table 3, footnotes b and c for calculation of test pressure). DBB testing per 6.6 or 6.7 closure test requirement in lieu of the testing method indicated in 6.5. 5.5 High-pressure Pneumatic Shell Test be performed after the hydrostatic shell test, using appropriate safety precautions. The pneumatic shell test order. Visible leakage is not allowed. 6 5.6 Test Fluid 5.6.1 inert gas, kerosene, water, or a noncorrosive liquid with a viscosity not higher than that of water. Unless otherwise 5.6.2 gas. 5.6.3 When air or gas is used for closure, shell, or backseat tests, the valve manufacturer shall be capable of demonstrating the adequacy of the method of leakage detection. 5.6.4 purchaser, a wetting agent and/or an antifreeze (e.g., glycol) shall be included in the water. For testing of austenitic stainless-steel valves, water with chloride content not exceeding 50 ppm shall be used. The valve manufacturer shall be able to document the chloride content. 5.7 Test Pressures 5.7.1 The shell test pressure shall be as listed in Table 2. 5.7.2 Backseat and closure test pressures shall be as listed in Table 3. 5.8 Test Duration Table 4.  7 Table 2—Shell Test Pressures d Shell Test Pressure (Minimum) Valve Type ASME class Pounds per Bar Gauge Square Inch Gauge (psig) 150 26 400 Ductile iron 300 66 975 Gray iron DN 50 to 300 (NPS 2 to 12) 25 350 DN 350 to 1200 (NPS 14 to 125 19 265 48) Gray iron DN 50 to 300 (NPS 2 to 12) 61 875 250 DN 350 to 600 (NPS 14 to 24) 37 525 Steel and nonferrous alloys Flanged 150 to 2500 b b Butt weld 150 to 4500 b b 800 c c Threaded a and socket weld 150 to 4500 b b a ASME B16.34 limits threaded-end valves to class 2500 and lower. b Per ASME B16.34, the hydrostatic shell test pressure shall be 11/2 times the pressure rating at 38 °C (100 °F), ambient working pressures lower than the primary valve assembly will require lower test pressures. c For class 800 valves, the hydrostatic shell test pressure shall be 11/2 times the pressure rating at 38 °C ratings. d Shell test pressure for API Standard 609 Category A valves shall be 11/2 times the maximum CWP of the valve. 8 Table 3—Backseat and Closure Test Pressures Test Pressure d Test Pounds per Bar Gauge Square Inch Gauge (psig) High-pressure closure and backseat a b b Low-pressure closure and backseat a 5.5 ± 1.5 80 ± 20 High-pressure closure c c Low-pressure closure 5.5 ± 1.5 80 ± 20 Check Valve High-pressure closure Class 125 (cast iron) DN 50 to 300 (NPS 2 to 12) 14 200 DN 350 to 1200 (NPS 14 to 48) 11 150 Class 250 (cast iron) DN 50 to 300 (NPS 2 to 12) 35 500 DN 350 to 600 (NPS 14 to 48) 21 300 Class 150 (ductile iron) 17 250 Class 300 (ductile iron) 44 640 Carbon, alloy, stainless steel, and special alloys b b Low-pressure closure (see Table 1) 5.5 ± 1.5 80 ± 20 a The backseat test is required for all valves that have the backseat feature, except for bellows seal valves. b 110 % of maximum allowable pressure at 38 °C (100 °F) in accordance with the applicable purchase c d Single values shown are minimum test pressures. Values with a tolerance indicate both minimum and maximum test pressures. Table 4—Duration of Required Test Pressure Valve Size Minimum Test Duration (Seconds) a Backseat Closure (for Valves Closure Check DN NPS Shell with Other Valves Valves Backseat b (API 594) Feature) 15 15 60 15 65 to 150 21/2 to 6 60 60 60 60 200 to 300 8 to 12 120 60 120 120 350 to 600 14 to 24 300 60 120 120 > 600 >24 600 120 240 240 a The test duration is the period of inspection after the valve is fully prepared and is under full pressure. b Test duration value provided is for each seat sealing direction (e.g., unidirectional).  9 5.9 Test Leakage 5.9.1 Shell, Stem Seals, and Backseat 5.9.1.1 test valve. 5.9.1.2 is not permitted. 5.9.1.3 For backseat tests, visually detectable leakage is not permitted. 5.9.1.4 For valves with adjustable stem seals, leakage through the stem seals during the shell test shall not be cause for rejection when tested at prescribed pressure and duration. However, the manufacturer shall demonstrate that the stem seals are capable of retaining pressure at least equal to the 38 °C (100 °F) valve rating without visible leakage. 5.9.1.5 leakage during the shell test is not permitted. 5.9.2 Closure 5.9.2.1 For both the low-pressure closure test and the high-pressure closure test, visual evidence of leakage through the disc, behind the seat rings, or past the shaft seals (of valves that have this feature) is not permitted and structural damage is not permitted [plastic (permanent) deformation of resilient seats and seals is not for the duration of the tests, is listed in Table 5. 5.9.2.2 The allowable leakage rate for closure tests of valves with nonmetallic (e.g., ceramic) seat materials Table 5 for a metal-seated valve of equivalent size and type. 10 Table 5—Maximum Allowable Leakage Rates for Closure Tests c Valve Size Metal Seated Valves Except Check Metal Seated Check Valves All Resilient- Liquid Liquid Gas Test a Gas DN NPS seated Test a Liquid Test Gas Test Gas Test Test (bubbles/ Test (mm) (in.) Valvesb (drops/ (ml/min) (m3/h) (ft3/h) (ml/min) min) (ml/min) min) 0 0b 0b 0b 0b 6 0.08 3 65 2 /2 1 0 5 0.31 10 0.10 7.5 0.11 3.75 80 3 0 6 0.38 12 0.12 9 0.13 4.5 100 4 0 8 0.50 16 0.16 12 0.17 6 125 5 0 10 0.63 20 0.20 15 0.21 7.5 150 6 0 12 0.75 24 0.24 18 0.25 9 200 8 0 16 1.00 32 0.32 24 0.34 12 250 10 0 20 1.25 40 0.40 30 0.42 15 300 12 0 24 1.50 48 0.48 36 0.50 18 350 14 0 28 1.75 56 0.56 42 0.59 21 400 16 0 32 2.00 64 0.64 48 0.67 24 450 18 0 36 2.25 72 0.72 54 0.76 27 500 20 0 40 2.50 80 0.80 60 0.84 30 600 24 0 48 3.00 96 0.96 72 1.01 36 650 26 0 52 3.25 104 1.04 78 1.09 39 700 28 0 56 3.50 112 1.12 84 1.18 42 750 30 0 60 3.75 120 1.20 90 1.26 45 800 32 0 64 4.00 128 1.28 96 1.34 48 900 36 0 72 4.50 144 1.44 108 1.51 54 1000 40 0 80 5.00 160 1.60 120 1.68 60 1050 42 0 84 5.25 168 1.68 126 1.76 63 1200 48 0 96 6.00 192 1.92 144 2.02 72 a For the liquid test, 1 mL is considered equivalent to 16 drops. For the gas test, 1 mL is considered equivalent to 100 bubbles. b Table 4). For a liquid test, 0 drops means no visible leakage per For a high-pressure pneumatic closure test, refer to 5.4. c Leakage rates for sizes above DN 1200 (NPS 48) shall be calculated by the following formulas: Liquid test for metal seated valves except check: 2 x NPS (drops/min) Gas test for metal seated valves except check: 4 x NPS (bubbles/min) Liquid test for metal seated check valves: 3 x NPS (cc/min) Gas test for metal seated check valves: 0.042 x NPS (m3/h) Gas test for metal seated check valves: 1.5 x NPS (ft3/h) 5.9.2.3 As an alternative, displacement measuring devices may be used, provided that the detectable leakage rate is equivalent to that given in Table 5, the valve manufacturer shall demonstrate and validate that the procedure yields results equivalent to the requirements of this standard, and the device has been accepted by agreement between the purchaser and the manufacturer. 5.9.2.4 When volumetric devices (bubblers) such as shown in Figure 1 are used to measure leakage, the calibrated to yield results equivalent to the units per minute listed in Table 5. 5.9.2.5 The tube end shall be cut square and smooth with no chamfers or burrs, and the tube axis shall be perpendicular to the surface of the water (see Figure 1).