Mss Sp-151-2016

MSS SP-151-2016

Pressure Testing of Knife Gate Valves

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: [email protected]

www.msshq.org

MSS

STANDARD PRACTICE

SP-151

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 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 Practice 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 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 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 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. 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 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 requirements. U.S. customary units in this Standard Practice are the standard; SI (metric) units are for reference only, unless SI (metric) units are the only units indicated. 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-151-2016 with permission 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 Fittings Industry Inc. All rights reserved. Originally Approved: August 2016 Originally Published: November 2016 MSS is a registered trademark of Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. Copyright ©, 2016 by Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. Printed in U.S.A.

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MSS

STANDARD PRACTICE

SP-151

FOREWORD This first edition of Standard Practice for Pressure Testing of Knife Gate Valves was approved and published in 2016. It was developed for the purpose of providing a uniform means of testing knife gate valves commonly used in the "full open" and "full closed" type of service for isolation. This Standard Practice is not intended for use with control valves. Refer to ISA 75.19.01 and FCI 70-2 for Control Valves. There are five distinct types of knife gate valves; all derived from the original patent in the 1950s. Each type offers a different performance and ability. There are two main groups: A) Cold Working Pressure (CWP) rated valves that do not adhere to ASME B16.34, and B) B16.34 Class 150, 300 and 600. In addition, there are two main Categories: C) Resilient Seated and D) Metal Seated. Modern advances in knife gate design have and will present additional types in the future; including designs which are ready for use now, such as Double Block and Bleed. It is the owner’s or specifier’s responsibility to be aware of the differences.

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MSS

STANDARD PRACTICE

SP-151

TABLE OF CONTENTS SECTION 1 2 3 4 5

PAGE

SCOPE ....................................................................................................................................... 1 DEFINITIONS ........................................................................................................................... 1 GENERAL REQUIREMENTS ................................................................................................. 2 SHELL LEAKAGE TESTS ....................................................................................................... 2 SEAT AND CLOSURE MEMBER TESTS .............................................................................. 3

TABLE 1 2 3 4

Shell Leakage Test Duration ...................................................................................................... 2 Alternate Gas Test ...................................................................................................................... 3 Seat and Closure Member Test Duration ................................................................................... 4 Units of Leakage per NPS/DN for Metal Seated Knife Gates ................................................... 4

ANNEX A

Referenced Standards and Applicable Dates ............................................................................ 5

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MSS

STANDARD PRACTICE

SP-151

PRESSURE TESTING OF KNIFE GATE VALVES 1. SCOPE This Standard Practice establishes requirements and acceptance criteria for shell and seat closure pressure testing of resilient, non-metallic (e.g. ceramic), and metal-to-metal seated knife gate valves of all types. 2. DEFINITIONS 2.1 Knife Gate Types 2.1.1 General Service MSS SP-148.

Knife gate valves for general purpose use designed to MSS SP-81 and

2.1.2 Severe Service MSS SP-146.

Knife gate valves for severe service use designed to MSS SP-135 and

2.2 No Visible Leakage 2.2.1 The term "no visible leakage", applied to a hydrostatic test liquid, is defined as a leak rate that will produce no visible weeping or formation of drops (1) at the test pressure and (2) for the duration of the test and (3) at the pressure containing boundary. 2.2.2 The term "no visible leakage", as applied to air or gas testing, is defined as a leak rate(l) that will produce no visible formation of bubbles in a water immersion test or after application of leak detection fluid at the (1) test pressure and (2) for the duration of the test and (3) at the pressure containing boundary. 2.3 Production Pressure Test Pressure tests that include closure member integrity, seat leakage, and shell integrity testing. Production pressure tests verify the pressure retaining and containing capability of production units manufactured for sale. 2.4 Seat and Closure Member Test An internal pressure test of flow regulating elements (seats, seals, and gate) to demonstrate static pressure performance within allowable leakage tolerances as required by the knife gate and seat type. 2.5 Shell Leakage Test An internal pressure test to prove out the integrity of the external pressure boundary. 2.6 Other Definitions Other definitions may be found in MSS SP-96.

NOTE: (1) The “leakage rate” (as noted in Section 2.4.2) is based on the measured leakage of nitrogen gas from a needle valve with a 0.167 in. (4.24 mm) O.D. x 0.091 in. (2.31 mm) I.D. tube submerged in water to a depth of 1 inch (25.4 mm). The tube end was cut square and smooth with no chamfers or butts and the tube axis was parallel to the surface of the water. Leakage was adjusted to a level equal to 40 bubbles in 10 minutes at 90 psig (6.0 bar). The 40 bubbles equaled 1.6 milliliter (ml) or, 1 bubble = 0.04 SCC. Using this data, a leak rate equivalent to 1 bubble every minute is found to be 4.1 x 10-5 in3/sec (6.7 x 10-4 ml/sec).

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MSS

STANDARD PRACTICE

SP-151

3. GENERAL REQUIREMENTS 3.1 The manufacturer shall be responsible for the performance of tests specified herein. 3.2 When ASME Class rated valves conform to the requirements of MSS SP-135, the testing requirements of ASME B16.34 shall also apply. 3.3 Production pressure tests (see Section 2.1) shall be performed on production units manufactured for sale. 3.4 The test fluid for the shell leakage test shall be water (which may contain a corrosion inhibitor), kerosene, or other fluid with viscosity not greater than that of water. Temperature of the test fluid shall not exceed 125 °F (52 °C). 3.5 The test fluid for seat and closure member test shall be air, inert gas, or liquid, such as water (which may contain a corrosion inhibitor), kerosene, or other fluid with viscosity not greater than that of water. Temperature of the test fluid shall not exceed 125 °F (52 °C). 3.6 Valves shall be substantially relieved of air or gas when tested with liquid. 3.7 Seat closure tests for NPS 4 (DN 100) and larger valves shall be conducted after an acceptable shell test. Seat closure tests for smaller valves may be conducted before or after the shell test at the manufacturer's option. 3.8 Valve test fixture loads applied to valve ends shall be limited to those required to effectively seal the valve ends. Bolt on flanges may be used for testing per agreement between manufacturer and purchaser. 3.9 Leakage detection devices, e.g., pressure decay devices, may be used for detecting leakage provided that they perform at the pressures specified in Sections 4 and 5. The valve manufacturer shall be able to demonstrate that, when these devices are used, the test results are equivalent to the requirements of this Standard Practice. 4. SHELL LEAKAGE TESTS 4.1 Each valve type shall be hydrostatically pressure tested at 1.5 times the valve’s 100 °F (38 °C) design pressure rating, rounded off to the next higher 25 psi (1.5 bar) increment. 4.2 Shell leakage tests shall be conducted with the valve in the partially open position and with the valve ends closed. 4.3 Visual leakage through the pressure boundary walls is not acceptable. Gate/Stem seal or packing leakage during the shell test shall not be cause for rejection. Stem seals or packing shall be capable of retaining pressure equal to the valve’s 100 °F (38 °C) design pressure rating without visible leakage. 4.4 The minimum duration of the shell leakage test shall be as per Table 1.

TABLE 1 – Shell Leakage Test Duration Valve Size

Test Time

NPS

DN

Seconds

≤2 2 2 – 6 8 – 12 ≥ 14

≤ 50 65 – 150 200 – 300 ≥ 350

15 60 120 300

1

2

MSS

STANDARD PRACTICE

SP-151

5. SEAT AND CLOSURE MEMBER TESTS 5.1 Valve designed for shutoff or isolation service shall be given a fluid seat leakage test. 5.1.1 After the shell test, each General Service valve shall receive a low pressure hydrostatic seat leakage test at 40 psi (2.8 bar) differential pressure in the direction of closure. Seat test duration shall be in accordance with Table 3. 5.1.2 The high pressure seat closure test shall be performed on all Severe Service valves at a fluid (liquid or gas) pressure no less than 1.1 times the valve’s 100 °F (38 °C) design pressure rating rounded to the next higher 5 psi (0.5 bar). Seat test duration shall be in accordance with Table 3. 5.1.3 At the manufacturer's option, a gas pressure of no less than 80 psi (5.5 bar) may be substituted for the valve sizes and pressure classes listed in Table 2.

TABLE 2 – Alternate Gas Test Valve Size

Pressure Class

NPS (DN)

Class

12 (300) and Smaller

300 and Lower

4 (100) and Smaller

All

5.1.4 Seat leakage testing shall be performed with seat surfaces free of materials that aid in sealing except as provided for in Sections 5.1.5 and 5.1.6. 5.1.5 When necessary to prevent damage during valve actuation, a light oil of viscosity no greater than that of kerosene may be applied to seating surfaces. 5.1.6 When lubricants are used for assembly operations, it is not required that these be removed prior to testing if their presence has no influence on the test results. 5.2 For valves of the double seating type, the test pressure shall be applied successively to each end of the closed valve and leakage to the opposite end checked. 5.2.1 Alternate method for valves with independent double seating (at the option of the manufacturer): the pressure may be applied inside the body of the closed valve and each seat checked for leakage at the valve ports, or the pressure may be applied to the valve ports and the sum of seat leakage checked at the body. 5.3 Valves conforming to this Standard Practice in all respects, except the following conditions, shall be tested as described in Section 5 of this Standard Practice; however, the closure test requirement may be reduced to 1.1 times the maximum rated closed position differential pressure if any of the follow conditions apply: 1) Valves that are designed for operating conditions that have pressure differential across the closure member limited to pressures less than the 100 °F (38 °C) pressure rating. 2) Valves having closure members and/or actuating devices (direct, mechanical, fluid, or electrical) that would be subject to damage at higher differential pressures. These exceptions may be exercised upon agreement between the purchaser and manufacturer. The manufacturer's name plate data shall include reference to any such limitations. 5.4 Valves of single or symmetrical seat design that are capable of seating in two directions require seat testing in both directions. 3

MSS

STANDARD PRACTICE

SP-151

5.5 Allowable leakage rates shall be as stated below: 5.5.1 The maximum allowable leakage for metal seated knife gate valves of each seat closure shall be as indicated in Table 4. 5.5.2 Valves having a resilient seat shall have no visible leakage for the duration of the seat test. 5.6 The duration of each seat closure test shall be per Table 3.

TABLE 3 – Seat and Closure Member Test Duration Valve Size

Test Time Seconds

NPS

DN

≤2

≤ 50

15

212 – 8

65 – 200

30

10 – 18

250 – 450

60

≥ 20

≥ 500

120

TABLE 4 – Units of Leakage per NPS/DN for Metal Seated Knife Gates Liquid Per NPS Per DN 40ml/min

1.6 ml/min

GENERAL NOTES: 1. 1 ml = 1 cubic centimeter (cc) 2. 1 ft3 = 0.02831685 m3 3. 0.0132 ft3/min. per DN = 0.000374 m3/min. per DN 4. 1 m3/min. = 1,000,000 cc/min.

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MSS

STANDARD PRACTICE

SP-151

ANNEX A Referenced Standards and Applicable Dates This Annex is an integral part of this Standard Practice and is placed after the main text for convenience. Standard Name

Description

ASME; ANSI/ASME B16.34-2013

Valves – Flanged, Threaded, and Welding End

FCI; ANSI/FCI 70-2-2013

Control Valve Seat Leakage

ISA; ANSI/ISA 75.19.01-2013

Hydrostatic Testing of Control Valves

MSS: ANSI/MSS SP-81-2013 SP-96-2011 SP-135-2016 SP-146-2014 SP-148-2014

Stainless-Steel or Stainless-Steel-Lined, Bonnetless, Knife Gate Valves with Flanged Ends Guidelines on Terminology for Valves and Fittings High Pressure Knife Gate Valves High Pressure, Lug- and Wafer-Type, Iron and Ductile Iron Knife Gate Valves Low Pressure Flanged or Lugged Carbon Steel and Iron or Ductile Iron, Cast or Fabricated, Bonnetless, Knife Gate Valves without Liners

The following organizations appear in the above list: ANSI

American National Standards Institute, Inc. 25 West 43rd Street, Fourth Floor New York, NY 10036-7406

ASME

American Society of Mechanical Engineers (ASME International) Two Park Avenue New York, NY 10016-5990

FCI

Fluid Controls Institute 1300 Sumner Avenue Cleveland, OH 44115-2851

ISA

International Society of Automation 67 T.W. Alexander Drive Research Triangle Park, NC 27709-2277

MSS

Manufacturers Standardization Society of the Valves and Fittings Industry 127 Park Street, NE Vienna, VA 22180-4602

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Purchase or View a Full Listing of MSS Standards at: http://msshq.org/Store/PriceList.cfm MSS Standard Practices (SPs) related to or referenced in this publication: ANSI/MSS SP-81

Stainless-Steel or Stainless-Steel-Lined, Bonnetless, Knife Gate Valves with Flanged Ends

ANSI/MSS SP-96

Guidelines on Terminology for Valves and Fittings

ANSI/MSS SP-135

High Pressure Knife Gate Valves

MSS SP-146

High Pressure, Lug- and Wafer-Type, Iron and Ductile Iron Knife Gate Valves

MSS SP-148

Low Pressure Flanged or Lugged Carbon Steel and Iron or Ductile Iron, Cast or Fabricated, Bonnetless, Knife Gate Valves without Liners –––––––––––

American National Standards Published by MSS, an ANSI-accredited Standards Developer: ANSI/MSS SP-25

Standard Marking System for Valves, Fittings, Flanges, and Unions

ANSI/MSS SP-44

Steel Pipeline Flanges

ANSI/MSS SP-55

Quality Standard for Steel Castings for Valves, Flanges, Fittings, and Other Piping Components – Visual Method for Evaluation of Surface Irregularities

ANSI/MSS SP-58

Pipe Hangers and Supports - Materials, Design, Manufacture, Selection, Application, and Installation

ANSI/MSS SP-96

Guidelines on Terminology for Valves and Fittings

ANSI/MSS SP-114

Corrosion Resistant Pipe Fittings Threaded and Socket Welding Class 150 and 1000

ANSI/MSS SP-134

Valves for Cryogenic Service, including Requirements for Body/Bonnet Extensions

ANSI/MSS SP-135

High Pressure Knife Gate Valves

ANSI/MSS SP-138

Quality Standard Practice for Oxygen Cleaning of Valves and Fittings

ANSI/MSS SP-144

Pressure Seal Bonnet Valves –––––––––––

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About MSS The Manufacturers Standardization Society (MSS) of the Valve and Fittings Industry is a non-profit technical association organized for development and improvement of industry, national and international codes and standards for Valves, Valve Actuators, Valve Modifications, Pipe Fittings, Flanges, Pipe Hangers and Supports, and Associated Seals. Since its establishment in 1924, MSS has been dedicated to developing standards for national and global applications, in cooperation with other standardizing bodies and regulatory authorities. For more information on membership and eligibility requirements, visit: http://msshq.org/Store/Membership.cfm Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. 127 Park Street, NE, Vienna, VA 22180-4620 • Phone (703) 281-6613 • Fax (703) 281-6671

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