1、MSS SP-154-2018 Low Pressure 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: s
2、tandardsmsshq.org www.msshq.org MSS STANDARD PRACTICE SP-154i 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
3、 provide an effective, 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 Practic
4、e does not in 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
5、 power, nor does 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
6、 indicated otherwise 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
7、the validity 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.
8、MSS shall not 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
9、 construed to 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 re
10、quirements. The U.S. customary units 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. Non-toleranc
11、ed 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-154-2018 with permission of the publisher, Manufacturers Standardization Society of the Valve and Fittings
12、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 Fittings Industry Inc. All rights reserved. Originally Approved: March 2018 Originally Pu
13、blished: March 2018 MSS is a registered trademark of Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. Copyright , 2018 by Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. Printed in U.S.A. MSS STANDARD PRACTICE SP-154ii TABLE OF CONTENTS SE
14、CTION PAGE 1 SCOPE AND FIELD OF APPLICATION 1 2 STANDARDS UNITS . 1 3 PRESSURE-TEMPERATURE RATINGS . 1 4 SIZE . 1 5 MATERIALS . 2 6 DESIGN . 2 7 TOLERANCES 3 8 PRODUCTION TESTS . 3 9 WELDING . 3 10 MARKING . 3 11 SHIPPING INFORMATION . 4 12 INSTALLATION . 4 TABLE 1 Pressure-Temperature Ratings 1 2 F
15、ace-to-Face Dimensions . 4 ANNEX A Referenced Standards and Applicable Dates 5 MSS STANDARD PRACTICE SP-1541 LOW PRESSURE KNIFE GATE VALVES FOR DOUBLE BLOCK AND BLEED 1. SCOPE AND FIELD OF APPLICATION 1.1 This Standard Practice covers stainless-steel-lined, cast, or fabricated bonnetless, low pressu
16、re knife gate valves that are designed and manufactured to serve as a “Double Block and Bleed”(1) 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 flanges for NPS 26
17、(DN 650) through NPS 36 (DN 900). 1.2 The valves identified in this Standard Practice are intended for use in applications where shock loadings are not encountered. Applications at conditions other than those specified in Section 3 require special design consideration. 1.3 The valves identified in t
18、his Standard Practice are intended for use in applications where a “Double Block and Bleed” type of isolation is required, and where two individual isolation valves with a removable or drain-containing spool piece between them is typically used. 2. STANDARD UNITS 2.1 The values stated in either U.S.
19、 customary units or SI (Metric) units are to be regarded as the standard. Within the text, the SI (Metric) units are shown in parenthesis. The values stated in each system may not be exact equivalents; therefore, each system must be used independently of the other. Combining or converting values fro
20、m the two systems may result in nonconformance with this Standard Practice. 3. PRESSURE-TEMPERATURE RATINGS 3.1 This Standard Practice covers values with a gauge pressure rating not exceeding the values in Table 1, at temperatures between 32 F and 150 F (0 C and 66 C). Higher pressure knife gate val
21、ves for double block and bleed involving Class 125, 150, 250, and 300 pressure-temperature ratings are addressed in MSS SP-152. TABLE 1 Pressure-Temperature Ratings U.S. Customary SI (Metric) NPS psi DN bar 2 24 150 50 600 10.3 30, 36 100 750, 990 6.9 4. SIZE 4.1 The valve sizes in Table 2 are equal
22、 to the nominal sizes of the end connections. NOTE: (1) For the purpose of this Standard Practice, “Double Block and Bleed” refers to a valve (or valve application) with two seating surfaces that, in the closed position, provide a seal against pressure from both ends of the valve with a means of ven
23、ting/bleeding the cavity between the seating surfaces. MSS STANDARD PRACTICE SP-1542 5. MATERIALS 5.1 Valves shall be constructed of Materials per the following codes and standards: 5.1.1 Carbon, Stainless, and Alloy Steels: MSS SP-81 5.1.2 Gray Iron: MSS SP-148 5.1.3 Ductile Iron: MSS SP-148 NOTE:
24、Unlisted materials may be used only by agreement between purchaser and the 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 by agreement between purchaser and the manufa
25、cturer in cases where abrasion or friction reducing overlays are used. 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 by a single actuator manufactured t
26、o MSS SP-81 or SP 148 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 isolated. The center isolation chamber also
27、 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. 6.1.2 Vent or purge ports (see Section 6.1.1)
28、 shall be a minimum of 5% of the valve size, but not less than 1/2 in. (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 agreement between purchaser and manufacturer
29、. 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 load. Because of variations in design, the manu
30、facturer 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 valve is closed and locked out. 6.4 The valve design shall prev
31、ent permanent distortion of the body or seat when tested, as specified in Section 8. 6.5 Unless otherwise specified by the customer, threaded holes for flange bolting shall be tapped in accordance with the applicable requirements in MSS SP-81 or MSS SP-148 based on body material. 6.6 The valve port
32、minimum flow diameter shall be equal to the port diameters listed in MSS SP-81 or MSS SP-148. 6.7 Because of variations in basic valve design, differential pressure, and valve accessibility, it is not possible to standardize the conditions under which a manually operated valve requires mechanical as
33、sistance. Consideration should be given to the use of mechanical assistance on all valves where the differential pressure, when operating, approaches the valves rated working pressure. In addition, consideration should be given to the use of mechanical assistance on all NPS 6 (DN 150) and larger val
34、ves, regardless of differential pressure. See MSS SP-91 for information and guidance relating to the use of mechanical assistance or manual operation of valves. MSS STANDARD PRACTICE SP-1543 6.8 Body Wall Thickness 6.8.1 All valves, center isolation chambers and drains/purges shall have a minimum wa
35、ll thickness as required by the standards listed in Section 5 of the appropriate size and rating marked on the identification plate. 6.8.2 When center isolation chambers are made from a pipe, the chamber must have a wall thickness that assures the same or better pressure-temperature rating than the
36、valves. 6.9 Face-to-face dimensions shall be in accordance with Table 2. 6.10 Flange bolt holes shall align radially within one (1) degree 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 (D
37、N 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 MSS SP-151. 8.2 Seat Test Each valve shall be seat tested in accordance with MSS SP-151. Valves shall have no detectable leakage for the duration of the seat
38、 test. 8.3 Center Isolation Chamber Test After successful completion of the seat and shell tests, the center isolation chamber shall be filled with fluid, pressurized and tested in accordance with Section 5.2 of MSS SP-151. Valves shall have no visible leakage from either seat for the duration of th
39、e test. 9. WELDING 9.1 Body pressure boundary welds shall be accordance with ASME Boiler and Pressure Vessel Code, Section IX, and shall meet the requirements of Section 2.1.6 of ASME B16.34. Abrasion resistant overlay welds are also acceptable by agreement between purchaser and the manufacturer. 10
40、. MARKING 10.1 Valves shall be marked in accordance with MSS SP-25, and in accordance with the following requirements and modifications: 10.1.1 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 inst
41、alling 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 between 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
42、one material or grade of material is used, each shall be identified. 4. Packing nuts may require adjustment to obtain a tight seal. 5. Proper operation of lockout device. NOTE: The stem material need not be listed. MSS STANDARD PRACTICE SP-1544 11. SHIPPING INFORMATION 11.1 Valve packing nuts may be
43、 loosened prior to shipment to extend packing life. These nuts may have to be adjusted after installation. 11.1.1 If packing nuts are loosened for shipment, there must be a tag attached indicating; (1) that they have been loosened and (2) include the procedure for proper tightening at installation.
44、See Section 10.1.1, Item 4. 11.2 Unless indicated otherwise, valves shall be shipped with covers to protect the raised faces of the flanges. 11.3 Valves may 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 resistan
45、ce 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 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
46、 to prevent packing leakage. TABLE 2 Face-to-Face Dimensions Valve Size Short Pattern Long Pattern NPS DN in. mm in. mm 2 3 4 6 50 80 100 150 3.75 3.75 3.75 4.00 95 95 95 102 7.50 7.50 7.50 9.25 191 191 191 235 8 10 12 200 250 300 5.13 5.13 5.75 130 130 146 9.88 9.88 10.38 251 251 264 14 16 18 350 4
47、00 450 5.75 6.50 6.50 146 165 165 11.13 12.00 12.50 283 305 318 20 24 500 600 8.13 8.13 206 206 14.50 14.50 368 368 30 36 750 900 12.25 14.75 311 375 15.50 16.25 394 413 MSS STANDARD PRACTICE SP-1545 ANNEX A Referenced Standards and Applicable Dates This Annex is an integral part of this Standard Pr
48、actice and is placed after the main text for convenience. Standard Name Description ASME; ANSI/ASME B16.34-2017 Valves Flanged, Threaded and Welding End B16.47-2017 Large Diameter Steel Flanges: NPS 26 Through NPS 60 Metric/Inch Standard B16.5-2017 Pipe Flanges and Flanged Fittings: NPS 1/2 through
49、NPS 24 Metric/Inch Standard BPVC-IX-2017 Boiler and Pressure Vessel Code, Section IX: Welding, Brazing, and Fusing Qualifications MSS; ANSI/MSS SP-25-2017 Standard Marking System for Valves, Fittings, Flanges, and Unions SP-44-2016 (2017 Reissue) Steel Pipeline Flanges SP-81-2017 Stainless Steel Lined, Bonnetless Knife Gate Valves with Flange Ends SP-91-2009 Guidelines for Manual Operation of Valves SP-148-2014 Low Pressure Flanged or Lugged Carbon Steel and Iron or Ductile Iron, Cast or Fabricated, Bonnetless, Knife Gate Valves Without Liners SP-151-2016 Pressure Testing
