1、MSS SP-152-2017 Knife Gate Valves for Double Block and Bleed Standard Practice Developed and Approved by the Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. 127 Park Street, NE Vienna, Virginia 22180-4602 Phone: (703) 281-6613 Fax: (703) 281-6671 E-mail: standardsmsshq
2、.org www.msshq.org MSS STANDARD PRACTICE SP-152i This MSS Standard Practice was developed under the consensus of the MSS Technical Committee 409, and the MSS Coordinating Committee. The content of this Standard Practice is the resulting efforts of competent and experienced volunteers to provide an e
3、ffective, clear, and non-exclusive standard that will benefit the industry as a whole. This MSS Standard Practice describes minimal requirements and is intended as a basis for common practice by the manufacturer, the user, and the general public. The existence of an MSS Standard Practice does not in
4、 itself preclude the manufacture, sale, or use of products not conforming to the Standard Practice. Mandatory conformance to this Standard Practice is established only by reference in other documents such as a code, specification, sales contract, or public law, as applicable. MSS has no power, nor d
5、oes it undertake, to enforce or certify compliance with this document. Any certification or other statement of compliance with the requirements of this Standard Practice shall not be attributable to MSS and is solely the responsibility of the certifier or maker of the statement. “Unless indicated ot
6、herwise within this MSS Standard Practice, other standards documents referenced to herein are identified by the date of issue that was applicable to this Standard Practice at the date of approval of this MSS Standard Practice (see Annex A). This Standard Practice shall remain silent on the validity
7、of those other standards of prior or subsequent dates of issue even though applicable provisions may not have changed.” By publication of this Standard Practice, no position is taken with respect to the validity of any potential claim(s) or of any patent rights in connection therewith. MSS shall not
8、 be held responsible for identifying any patent rights. Users are expressly advised that determination of patent rights and the risk of infringement of such rights are entirely their responsibility. In this Standard Practice, all text, notes, annexes, tables, figures, and references are construed to
9、 be essential to the understanding of the message of the standard, and are considered normative unless indicated as “supplemental”. All appendices, if included, that appear in this document are construed as “supplemental”. Note that supplemental information does not include mandatory requirements. T
10、he U.S. customary and SI (metric) units in this Standard Practice are regarded separately as the standard; each should be used independently of the other. Combining or converting values between the two systems may result in non-conformance with this Standard Practice. The U.S. customary units in thi
11、s Standard Practice are the standard, in cases of conflict or incongruity. Non-toleranced dimensions in this Standard Practice are nominal unless otherwise specified. Excerpts of this Standard Practice may be quoted with permission. Credit lines should read Extracted from MSS SP-152-2017 with permis
12、sion of the publisher, Manufacturers Standardization Society of the Valve and Fittings Industry. Reproduction and/or electronic transmission or dissemination is prohibited under copyright convention unless written permission is granted by the Manufacturers Standardization Society of the Valve and Fi
13、ttings Industry Inc. All rights reserved. Originally Approved: August 2017 Originally Published: November 2017 MSS is a registered trademark of Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. Copyright , 2017 by Manufacturers Standardization Society of the Valve and Fi
14、ttings Industry, Inc. Printed in U.S.A. MSS STANDARD PRACTICE SP-152ii TABLE OF CONTENTS SECTION PAGE 1 SCOPE AND FIELD OF APPLICATION 1 2 STANDARD UNITS . 1 3 PRESSURE-TEMPERATURE RATINGS . 1 4 SIZE . 1 5 MATERIALS . 1 6 DESIGN . 2 7 TOLERANCES 3 8 PRODUCTION TESTS . 3 9 WELDING 3 10 MARKING . 3 11
15、 SHIPPING INFORMATION . 4 12 INSTALLATION . 4 TABLE 1 Long Pattern . 5 2 Short Pattern . 5 ANNEX A Referenced Standards and Applicable Dates 6 MSS STANDARD PRACTICE SP-1521 KNIFE GATE VALVES FOR DOUBLE BLOCK AND BLEED 1. SCOPE AND FIELD OF APPLICATION 1.1 This Standard Practice covers cast or fabric
16、ated, bonneted or bonnetless knife gate valves designed and manufactured to serve as a “Double Block and Bleed” single valve system in pipelines. These valve types shall have flanged body designs compatible with ASME B16.5 flanges for NPS 2 (DN 50) through NPS 24 (DN 600), ASME B16.47 Series A flang
17、es for NPS 26 (DN 650) through NPS 36 (DN 900), and ASME B16.42 for sizes greater than NPS 36 (DN 900). 1.2 The valves identified in this Standard Practice are intended for use in applications where a “Double Block and Bleed” type of isolation is required, and where two (2) individual isolation valv
18、es with a removable or drain-containing spool piece between them is typically used. NOTE: For the purposes of this Standard Practice, “Double Block and Bleed” refers to a valve (or valve application) with two seating surfaces that, in the closed position, provides a seal against pressure from both e
19、nds of the valve with a means of venting/bleeding the cavity between the seating surfaces. 2. STANDARD UNITS 2.1 The values stated in either U.S. customary units or SI (metric) units are to be regarded separately as the standard. Within the text, the SI (metric) units are shown in parenthesis. The v
20、alues stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with this Standard Practice. 3. PRESSURE-TEMPERATURE RATINGS 3.1 This Standard Practice is limited to valves with
21、Class 125, 150, 250, and 300 pressure-temperature ratings, per the appropriate ASME standards or codes listed in Section 5. 3.2 Valves not meeting the wall thickness requirements may be pressure-temperature rated by the manufacturer in accordance with proof pressure test data requirements of UG-101
22、of ASME Boiler and Pressure Vessel Code, Section VIII, Division I. The manufacturers rating shall not exceed the applicable standard flanged valve rating of ASME standards or codes for the applicable body material. 4. SIZE 4.1 The valve sizes in Table 1 and Table 2 are equal to the nominal sizes of
23、the end connections. 5. MATERIALS 5.1 Valves shall be constructed of Materials per the following codes and standards: 5.1.1 Carbon, Stainless and Alloy Steels: ASME B16.5, ASME B16.34, ASME B16.47, and MSS SP-135. 5.1.2 Gray Iron: ASME B16.1 and MSS SP-146. 5.1.3 Ductile Irons: ASME B16.42 and MSS S
24、P-146. NOTE: Unlisted materials may be used only by agreement between purchaser and manufacturer. 5.2 Internal parts, center isolation chambers and drains/purges shall have a corrosion resistance equivalent to or better than the valve body. Exceptions may be made per agreement between purchaser and
25、manufacturer in cases where abrasion or friction reducing overlays are used. MSS STANDARD PRACTICE SP-1522 6. DESIGN 6.1 The design of these valves shall consist of a fully flanged (cast or fabricated) body with two independent seats, two sets of packing or gate seals, two independent gates operated
26、 by a single actuator manufactured to MSS SP-135 or MSS SP-146, and a center isolation chamber located between the gates. INFORMATIONAL NOTE: The center isolation chamber is located between two valve seats (as a component of the final product) and allows for the upstream or downstream piping to be i
27、solated. The center isolation chamber also contains vents for pressure relief. 6.1.1 The center isolation chamber shall have a minimum of three (3) threaded vent/purge ports located around the outside perimeter of the body to allow for verification of isolation, and also for purging if required. 6.1
28、.2 Vent or purge ports (see Section 6.1.1) shall be a minimum of 5% of the valve size, but not less than 1/2 inch (12 mm), and be adequate to prevent plugging, which causes pressurization of the center isolation chamber in the event of valve seat leakage. Larger vent/purge ports may be provided per
29、agreement between purchaser and manufacturer. 6.2 Valves shall be equipped with a positive type lockout device for the open and closed positions that prevents the gates from moving off of the seats when in place and locked. The lockout device shall be capable of withstanding the maximum actuator loa
30、d. Because of variances in design, the manufacturer shall provide instructions for the proper operation of the lockout device. 6.3 The design of each valve shall provide a bubble tight, bi-directional seal, with no leakage allowed into or out of the center isolation chamber when the valve is closed
31、and locked out. 6.4 The valve design shall prevent permanent distortion of the body or seat when tested, as specified in Section 8. 6.5 Threaded holes used for flange bolting shall provide for full thread engagement to a depth of not less than the nominal bolt diameter. Unless otherwise specified by
32、 the customer, threaded holes for flange bolting shall be tapped in accordance with the applicable requirements in MSS SP-135 and MSS SP-146. 6.6 The valve port minimum flow diameter shall be equal to the ASME standards and codes listed in Section 5. 6.7 Because of variations in basic valve design,
33、differential pressure, and valve accessibility, it is not possible to standardize the conditions under which a manually operated valve requires mechanical assistance. Consideration should be given to the use of mechanical assistance on all valves where the differential pressure, when operating, appr
34、oaches the valves rated working pressure. In addition, consideration should be given to the use of mechanical assistance on all NPS 6 (DN 150) valves and larger, regardless of differential pressure. See MSS SP-91 for information and guidance relating to the use of mechanical assistance or manual ope
35、ration of valves. 6.8 Body Wall Thickness 6.8.1 All valves, center isolation chambers and drains/purges shall have minimum wall thickness as required by the ASME standards or codes listed in Section 5 of the appropriate size and Pressure Class for the rating marked on the identification plate. 6.8.2
36、 As an alternative to Section 6.8.1, valve assemblies with valve bodies not meeting the appropriate ASME wall thickness for the appropriate class shall have the maximum allowable pressure determined by using a vessel proof test in accordance with UG-101 of ASME Boiler and Pressure Vessel Code, Secti
37、on VIII, Division I (see Section 3.2 of this Standard Practice). Documentation records of successful proof test data shall be available at the manufacturers facility for inspection by the purchaser. MSS STANDARD PRACTICE SP-1523 When center isolation chambers are made from pipe, the chamber must hav
38、e a wall thickness that assures the same or a better pressure-temperature rating than the valves. 6.9 Bonnets, when required, shall be of the bolted design. 6.10 Face-to-face dimensions shall be in accordance with Table 1 and Table 2. 6.11 Flange bolt holes shall align radially within one (1) degree
39、 from end-to-end of assembly. 7. TOLERANCES 7.1 The following tolerances shall be followed: Face-to-Face: NPS 10 (DN 250) and smaller: 0.12 in. (3 mm) NPS 12 (DN 300) and larger: 0.25 in. (6 mm) 8. PRODUCTION TESTS 8.1 Shell Test Each valve shall be hydrostatically pressure tested in accordance with
40、 MSS SP-151 and API 598. 8.2 Seat Test Each valve shall be seat tested in accordance with MSS SP-151 and API 598. Valves shall have no detectable leakage for the duration of the seat test. 8.3 Center Isolation Chamber Test After successful completion of the seat and shell tests, the center isolation
41、 chamber shall be tested in accordance with Section 5.2. of MSS SP-151. Valves shall have no visible leakage from either side of the port for the duration of the test. 9. WELDING 9.1 Body pressure boundary welds shall be in accordance with ASME Boiler and Pressure Vessel Code, Section IX, and shall
42、meet the requirements of Section 2.1.6 of ASME B16.34. Abrasion resistant overlay welds are also acceptable per agreement between purchaser and manufacturer. 10. MARKING 10.1 Valves shall be marked in accordance with MSS SP-25, and in accordance with the following requirements and modifications: 10.
43、1.1 A tag or weatherproof label shall be attached to the valve(s) for installation purposes, indicating the following information: 1. Care to be taken when installing studs or bolts in the tapped holes of the flange in the area of the chest, to prevent chest damage. The chest is the body area betwee
44、n the packing chamber and the flanges. 2. Manufacturers name, trademark, or logo. 3. The body, gate, and seal materials of construction or code. When more than one material or grade of material is used, each shall be identified. 4. Packing nuts may require adjustment to obtain a tight seal. 5. Prope
45、r operation of lockout device. NOTE: The stem material need not be listed. MSS STANDARD PRACTICE SP-1524 11. SHIPPING INFORMATION 11.1 Valve packing nuts may be loosened prior to shipment to extend packing life. These nuts may have to be adjusted after installation. 11.1.1 If packing nuts are loosen
46、ed for shipment, there must be a tag attached indicating they have been loosen and the procedure for proper tightening at installation (see Section 10.1.1, Items 1 to 4). 11.3 Unless indicated otherwise, valves shall be shipped with covers to protect the raised faces of the flanges. 11.4 Valves may
47、be shipped with plastic protective plugs in the vent/purge ports, or with plugs of a material that is equal to or greater in corrosion resistance to the body material. 12. INSTALLATION 12.1 When bolting cast iron valves to steel flanges, recommendations in Section 5.3.5 of ASME B16.5 and Section 9.5
48、 of MSS SP-44 should be considered so as to prevent damage to the valve. 12.2 Valve packing may need to be adjusted when the valve is installed to prevent packing leakage. MSS STANDARD PRACTICE SP-1525 TABLE 1 Long Pattern Valve Size Face-to-Face Dimension NPS DN Class 125/150 (in.) Class 125/150 (m
49、m) Class 250/300 (in.) Class 250/300 (mm) 2 3 4 6 50 80 100 150 9.00 11.50 11.75 9.75 229 292 298 248 9.00 11.50 11.75 12.63 229 292 298 321 8 10 12 200 250 300 10.13 10.63 10.88 257 270 276 13.63 15.13 15.63 346 384 397 14 16 18 350 400 450 12.38 12.50 13.75 314 317 349 16.88 17.63 19.50 429 448 495 20 24 500 600 14.50 15.50 368 394 20.38 20.50 518 521 30 36 750 900 21.25 24.25 540 616 27.50 30.50 699 775 42 48 1050 1200 26.00 29.50 660 749 38.50 40.00 978 1016 TABLE 2 Short Pattern Valve Size Face-to-Face Dimension NPS DN Class 125/150 (in.) Class 125/150(mm) Class 250/3
