valvulas para servicio criogenico.pdf

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MSS STANDARD PRACTICE SP-134

i

This MSS Standard Practice was developed under the consensus of the MSS Technical Committee 114 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. ThisMSS 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 thisdocument. 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 B). This StandardPractice 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.

This document has been substantially revised from the previous 2010 edition. It is

suggested that if the user is interested in knowing what changes have been made,

that direct page by page comparison should be made of this document and that of

the previous edition.

Non-toleranced dimensions in this Standard Practice are nominal and, unless otherwise specified, shall be considered

for reference only.

Excerpts of this Standard Practice may be quoted with permission. Credit lines should read Extracted from

MSS SP-134-2012 with permission of the publisher, Manufacturers Standardization Society of the Valve and

Fitt ings 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: February 2005

Originally Published: July 2006

Current Edition Approved: December 2011Current Edition Published: May 2012

MSS is a registered trademark of Manufacturers Standardization Society of the Valve and Fittings Industry, Inc.

Copyright 2012 by

Manufacturers Standardization Society

of theValve and Fittings Industry, Inc.

Printed in U.S.A.

yright MSSded by IHS under license with MSS

Not for Resaleeproduction or networking permitted without license from I HS

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TABLE OF CONTENTS

SECTION PAGE

1 SCOPE ..................................................................................................................................................... 12 DEFINITIONS ........................................................................................................................................ 1

3 CLASS/SIZE DESIGNATION ............................................................................................................... 2

4 MATERIALS .......................................................................................................................................... 2

5 DESIGN .................................................................................................................................................. 2

6 GATE AND GLOBE VALVES .............................................................................................................. 3

7 BALL & BUTTERFLY VALVES .......................................................................................................... 4

8 EXTENSION LENGTH .......................................................................................................................... 4

9 FABRICATION ...................................................................................................................................... 4

10 PRODUCTION PRESSURE TESTING ................................................................................................. 4

11 LOW TEMPERATURE CRYOGENIC TESTING ................................................................................ 5

TABLE

1 Body/Bonnet Extension Length, U.S. Customary Units ......................................................................... 6

2 Body/Bonnet Extension Length, SI Metric Units .................................................................................... 6

A1 Allowable Seat Leakage Rates for Cryogenic Closure Tests ................................................................ 14

A2 Helium Test Pressures ........................................................................................................................... 14

FIGURE

1 Typical Outside Screw and Yoke Cryogenic Globe Valve ..................................................................... 7

2 Typical Outside Screw and Yoke Cryogenic Gate Valve ....................................................................... 8

3 Typical Cryogenic Ball Valve ................................................................................................................. 9

4 Typical Cryogenic Butterfly Valve ....................................................................................................... 10

A1 Typical Test Set-Up ............................................................................................................................... 14

ANNEX

A Low Temperature Cryogenic Testing .................................................................................................... 11

B Referenced Standards and Applicable Dates ......................................................................................... 15

APPENDIX

X1 Guidance for Stem Strength Calculations .............................................................................................. 16



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1. SCOPE

1.1 This Standard Practice covers

requirements for material, design, dimensions,fabrication, non-destructive examination and

pressure testing of stainless steel and other

alloy cryogenic service valves with

body/bonnet extensions. Requirements for

check valves for cryogenic service, which may

not require body/bonnet extensions, are also

covered. This Standard Practice applies to

cryogenic gate, globe, butterfly, ball, and

check valves, and may be used in conjunction

with other valve-specific standards; including

the following identified in this Standard

Practice as a parent standard:

ASME B16.34, Valves Flanged,

Threaded, and Welding End

API 600, Steel Gate Valves Flanged

and Butt-welding Ends, Bolted Bonnets

API 602, Steel Gate, Globe, and Check

Valves for Sizes NPS 4 (DN 100) and

Smaller for the Petroleum and Natural

Gas Industries

API 603, Corrosion-resistant, Bolted

Bonnet Gate Valves Flanged and Butt-welding Ends

API 608, Metal Ball Valves Flanged,

Threaded and Welding Ends

API 609, Butterfly Valves: Double

Flanged, Lug- and Wafer-type

API 6D, Specification for Pipeline

Valves (identical to ISO 14313)

1.2 The requirements in this Standard

Practice are not intended to supersede or

replace requirements of a parent valve standard.

1.3 This Standard Practice includes

additional construction detail requirements

specifically related to valves, including

body/bonnet extensions essential for

cryogenic applications.

2. DEFINITIONS

2.1 General Definitions given in MSS SP-

96 apply to this Standard Practice.

2.2 Cryogenics The science of materials at

extremely low temperatures.

2.3 Cryogenic Fluid A gas that can be

changed to a liquid by removal of heat by

refrigeration methods to a temperature at

-100 F (-73 C) or lower.

2.4 Cryogenic Temperature For this

Standard Practice a temperature range of-100F (-73 C) to -425 F (-254 C) is cryogenic.

2.5 Cold Box An enclosure that insulates a

set of equipment from the environment

without the need for insulation of theindividual components inside the cold box.

2.6 Cold Box Extension A valve

body/bonnet extension section that removes

the operating mechanism of the valve outside

the cold box and is required to be longer than

a non-cold box extension.

2.7 Non-Cold Box Extension Abody/bonnet extension that is used for valves

that are normally individually insulated.

2.8 Parent Valve Standard Endorses the

ASME B16.34 construction requirements but

has additional construction detail requirements

exceeding or not addressed by ASME B16.34.

2.9 Gas Column That portion ofbody/bonnet extension that allows for the

formation of an insulating column of vapor.

2.10 Double Block and Bleed Valve Valve

with two seating surfaces that when in the

closed position, blocks flow from both valve

ends when the cavity between the seating

surfaces is vented through a bleed connection

provided in the valve body.

VALVES FOR CRYOGENIC SERVICE,INCLUDING REQUIREMENTS FOR BODY/BONNET EXTENSIONS




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3. CLASS/SIZE DESIGNATION

3.1 Pressure Rating Designation Class,

followed by a dimensional number, is the

designation for pressure-temperature ratings.

Standardized designations are as follows:

Class150 300 400 600

900 1500 2500 4500

3.2 Size NPS indicates Nominal Pipe Size

(U.S customary). A standard size identification

number, not necessarily an actual dimension.

The (SI) metric-based equivalent is called DN or

Nominal Diameter/"diametre nominel". NPS is

related to the reference DN (used in many

international standards). The typical relationship

is as follows:

NPS DN

1/4 8

3/8 10

1/2 15

3/4 20

1 25

11/4 32

11/2 40

2 50

21/2 65

3 804 100

For NPS 4, the related DN = 25multiplied by the NPS number.

4. MATERIALS

4.1 Materials in contact with cryogenic fluid

or exposed to cryogenic temperatures shall be

suitable for use at the minimum temperature

specified by the purchase order. ASME B31.3,

Table A1 lists mechanical properties for

materials at temperatures as low as-425 F (-254 C).

4.2 Body, bonnet, body/bonnet extension,

and pressure retaining bolting shall be of

materials listed in ASME B 16.34, Table 1

and also listed in ASME B31.3, Table A1

for the cryogenic valve design temperature.

The body/bonnet extension shall be constructed

of the same ASME B16.34 Table 1 group

material as the valve body group material or a

similar ASME B16.34 group material with the

same cryogenic material compatibility as the

valve body.

4.3 Unless otherwise specified in the

purchase order internal wetted parts shall

be made of a material that is suitable for

the specified cryogenic temperature and has

a corrosion resistance that is comparable

with the body material.

4.4 Packing and gasket materials in direct

contact with the service fluid shall be capable

of operating at temperatures from +150 F

(+65 C) to the lowest cryogenic temperature

of the service fluid specified in the purchaseorder.

4.5 When pipe or non-standard wall tube

material is used for constructing body/bonnet

extensions, the material shall be seamless.

5. DESIGN

5.1 The requirements of ASME B16.34,

Section 2.1.6, shall be met for weld fabricated

body/bonnet extensions.

5.2 Valves shall have a body/bonnetextension integrally cast/forged or consisting

of a pipe or non-standard wall tube that

distances the stem packing and valve

operating mechanism from the cryogenic fluid

in the valve body/bonnet extension that might

otherwise damage or impair the function of

these items. The body/bonnet extension shall

be of sufficient length to provide an insulating

gas column that prevents the packing area and

operating mechanism from freezing.

Check valves do not require extensions except

when they are designed for stop-check service.

Stop check valve extensions shall follow this

Standard Practice rules for cryogenic globe

valves.

The purchaser shall provide the body/bonnet

extension length when Table 1 or Table 2

extension lengths are not adequate.



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5.2.1 The cast/forged extension, pipe or

non-standard wall tube thickness shall take

into account pressure stresses as well as

operating torque, stem thrust and bending

stresses induced by handwheels, gears and

power actuators.

5.2.2 The body/bonnet extension shall

meet the minimum wall thickness

requirements of ASME B16.34, Section

6.1.3, for the applicable pressure class of the

valve body unless a greater wall thickness is

specified by the parent valve specification. If

the body/bonnet extension is made from a

different ASME B16.34, Table 1, material

than the valve body and has an ASME

B16.34 pressure-temperature rating less than

the valve body, then the extension thickness

must be increased proportionately to meet thepressure-temperature rating of the body at all

applicable temperatures.

5.3 Valves shall be designed for operating at

temperatures from +150 F (+65 C) to the

lowest cryogenic temperature of the service

fluid.

5.4 The pressure rating of the valve at

service temperatures below -20 F (-29 C)

shall not exceed the ASME B16.34 pressure

rating at -20 F (-29 C) to 100 F (38 C) for

the applicable valve body material and

appropriate Class designation.

5.5 Body/Bonnet Extensions

5.5.1 Body/Bonnet Extensions should be

used primarily for temperatures colder than

-100 F (-73 C). When specified by the

purchaser this Standard Practice may also be

used for valves with body/bonnet extensions

for low temperature applications for

temperatures warmer than -100 F (-73 C).

5.5.2 Stem to extension tube diametrical

clearance should be minimized to help reduce

convective heat losses.

5.5.3 For cold box applications, valves with

extended body/bonnets shall be capable of

operating with the stem oriented from 150 to

900above the horizontal plane.

5.5.4 Valves with extended body/bonnets in

cryogenic gas service shall be capable of

operating in any stem orientation unless

otherwise limited by the manufacturer.

5.6 Valve Stems The design of globe,

gate, and quarter-turn valves having extendedstem lengths, as required by this Standard

Practice, introduces stem buckling and angle

of twist design inputs that shall be considered

in the valve design.

Specifically for stem buckling design

considerations, a number of different model

equations, based on stem guiding end designs

(fixed, pinned, or combination thereof), are

available to the designer for consideration.

For moderate length stems where combinedcompression/buckling failure mode may

occur, there are many empirical equations

that can be used. These multiple model and

empirical equations are a deterrent to

standardization of stem design methods.

Appendix X1 is offered as a guideline for stem

design, which may be used by manufacturers

that subscribe to the models and empirical

equations used in the Appendix.

5.6.1 Stem calculations are a requirement of

this Standard Practice and the manufacturer

shall utilize the guidance of Appendix XI or

other stem model derivatives to arrive at such

calculations.

6. GATE & GLOBE VALVES

6.1 Gate valves shall be provided with a

means for allowing any pressure increase in

the body/bonnet extension cavity to be vented

to the high pressure side of the closed

obturator, such as a vent hole on the higher

pressure side of the wedge, unless otherwisespecified in the purchase order.

Double block and bleed valves shall be vented

using some form of a pressure relief device

that does not violate the dual seating

requirement of the valve.



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6.2 A flow arrow indicating flow direction

for uni-directional valves shall be cast,

stamped, or etched on the valve body.

Alternatively, a flow arrow tag may be

attached by welding to the valve body.

6.3 Backseats, when utilized, may be at the

bottom or at the top of the body/bonnet

extension. Backseats provided at the bottom of

a bonnet extension may cause excessive

increase of extension cavity pressure. Valves

with bottom backseats shall be designed with a

provision to protect from excessive cavity

pressure buildup.

7. BALL & BUTTERFLY VALVES

7.1 Ball valves shall be provided with a

provision to vent the body and bonnetextension cavity to the upstream side of the

closed ball, either by drilling a bleed hole in

the ball or by other means of protection

against over-pressurization of the body/bonnet

extension cavity.

Double block and bleed valves shall be vented

using some form of a pressure relief device

that does not violate the dual seating

requirement of the valve.

7.2 A flow arrow indicating flow directionshall be cast, stamped, or etched on the valve

body. Alternatively, an arrow tag may be

attached by welding to the valve body. For bi-

directional ball valves, including block and

bleed, a flow arrow indicating flow direction

is not required.

8. EXTENSION LENGTH

8.1 Minimum extension lengths for rising

stem gate/globe valves and for quarter-turn

valves shall be per Tables 1 and 2, unless

otherwise specified in the purchase order.

8.2 Cold box valve dimensions are for

valves with body/bonnet extensions on valves

in cryogenic liquid/vapor service, which have

installation orientation restrictions. SeeSection 5.5.3.

8.3 Non-cold box valve dimensions are for

those valves with body/bonnet extensions for

valves in cryogenic gas or liquid service, with

the orientations of Sections 5.5.3 or 5.5.4 as

applicable.

9. FABRICATION

9.1 Valves fabricated by welding shall be

done in accordance with ASME B16.34,

Section 2.1.6.

9.2 Welding procedures, welders, and

welding operators, shall be qualified under the

provisions of ASME Boiler and Pressure

Vessel Code, Section VIII, Division 1. Welding

requirements of the parent standard shall be

met when specified in the purchase order.

9.3 The weld configuration of the bonnetextension tube to body/bonnet connections

may be full penetration Vee groove, partial

penetration Vee groove or fillet type. Full

strength threaded joints with seal welds can

also be used.

9.4 Non-destructive examination of welds

shall be performed per ASME Boiler and

Pressure Vessel Code, Section VIII, Division 1

to achieve a joint efficiency as required by

ASME B16.34, Section 2.1.6.

Weld quality requirements of the parent

standard shall be met when specified in the

purchase order.

10. PRODUCTION PRESSURE TESTING

10.1 Prior to testing, each valve shall be

cleaned and degreased as specified in the

purchase order.

10.2 Each valve shall be shell and closure

tested as required by ASME B16.34. Each valve

shall be tested in accordance with the parentstandard when specified in the purchase order.

10.3 Following ASME B16.34 final testing,

each valve shall be dried of all water test

solution trapped in the valve.



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10.4 Each fabricated body/bonnet extension

shall be subjected to a supplemental

pneumatic testing with inert gas at 80-100 psig

(5.5-6.9 barg) for a minimum duration of 60

seconds. No visible bubble leakage is allowed

through welds or the pressure boundary as

determined by testing under water, with anapplied foaming solution, or with a mass leak

detection device.

11. LOW TEMPERATURE CRYOGENIC

TESTING

11.1 Cryogenic qualification or production

testing, when specified for an item or a sample

of an item by the purchase order or agreement

between purchaser and manufacturer, shall be

performed per the requirements of Annex A.



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TABLE 1

Body/Bonnet Extension Length, U.S. Customary Units

Dimensions are in inches.

Size

(NPS)

Rising-Stem Valves Quarter-turn Valves

Cold Box Non-Cold Box Cold Box Non-Cold Box

1/2 17 12 16 7.53/4 17 12 16 7.5

1 17 12 16 7.5

11/2 21 14 20 8.5

2 21 16 20 10

3 24 18 22 13

4 26 22 24 14

6 30 24 24 17

8 34 27 26 18

10 40 32 28 25

12 45 36 32 28

Dimensions Centerline of valve to top of stuffing box.See Section 8 and Figures 1, 2, 3, and 4.

TABLE 2

Body/Bonnet Extension Length, SI (Metric) Units

Dimensions are in millimeters.

Size

(DN)

Rising-Stem Valves Quarter-turn Valves

Cold Box Non-Cold Box Cold Box Non-Cold Box

15 425 300 400 200

20 425 300 400 20025 425 300 400 200

40 500 350 500 225

50 500 400 500 250

80 600 450 550 300

100 650 550 600 350

150 750 600 600 425

200 900 700 650 450

250 1000 800 700 600

300 1150 900 800 700

Dimensions Centerline of valve to top of stuffing box.

See Section 8 and Figures 1, 2, 3, and 4.




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PART NAMES

1. Handwheel Nut

2. Identification Plate3. Handwheel

4. Stem Nut

5. Gland

6. Gland Bolting

7. Yoke

8. Packing

9. Stem

10. Bonnet Extension

11. Bonnet Bolting

12. Bonnet

13. Gasket

14. Disc Nut15. Disc

16. Body

FIGURE 1Typical Outside Screw and Yoke Cryogenic Globe Valve

(For Illustration Only)



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PART NAMES

1. Handwheel Nut2. Identification Plate

3. Handwheel

4. Stem Nut

5. Gland Bolting

6. Gland

7. Packing

8. Stem

9. Bonnet Extension

10. Bonnet Bolting

11. Bonnet

12. Gasket

13. Seat Ring14. Gate

15. Body

FIGURE 2Typical Outside Screw and Yoke Cryogenic Gate Valve




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PART NAMES

1. Body

2. Bonnet

4. Stem

5. Ball

6. Thrust Washer

7. Stem Bushing

9. Seat

11. Packing Flange

12. Gland Bushing

13. Packing Ring

15. Stud

16. Nut

19. Gasket

33. Handle

46. Spring

55. Bushing

56. Hex Head Caps Screw

63. Packing Washer

90. Extension

FIGURE 3Typical Cryogenic Ball Valve

For Illustration Onl



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PART NAMES

1. Gear Actuator

2. Handwheel

3. Handwheel Pin

4. Mounting Bracket

5. Mounting Bolt

6. Upper Journal Bearing

7. Packing

8. Housing Extension

9. Stem

10. Stop Bearing

11. Thrust/Journal Bearing

12. Disk

13. Body

14. Packing Stud

15. Packing Bolt

16. Packing Follower

FIGURE 4Typical Cryogenic Butterfly Valve




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A1. CRYOGENIC VALVE TEST FLUIDS

A1.1 Cryogenic valves constructed of

materials suitable for use in temperatures in the-150 F to -425 F (-100 C to -255 C) range

(examples: Group 2 and Group 3 materials of

ASME B16.34) and requiring qualification or

production testing by the purchase order shall

be tested using liquid nitrogen as the immersion

and cool down test fluid.

A1.2 Cryogenic valves constructed of alloy

steel materials suitable for use in the -100F to

-150 F (-73 C to -100 C) range (examples:

A352 LC2 and A352 LC3, Group 1 materials

of ASME B16.34) and requiring qualificationor production testing by the purchase order

shall be tested using a immersion liquid

acceptable for the cryogenic temperature

(examples: heat transfer fluid or ethylene

glycol), which shall be cooled by control flow

through coils of liquid nitrogen or mechanical

refrigeration or by addition of cooling media

directly to the immersion fluid. Alternately the

valve body may be cooled in a closed

insulated box using nitrogen vapors or

mechanical refrigeration methods without the

use of an immersion liquid.

A2. PRELIMINARY TEST PREPARATIONS

A2.1 The valve or valves shall be pre-tested

in accordance with parent valve standard at

ambient temperature.

A2.2 The valve or valves shall be purgedwith clean dry nitrogen or air to remove any

remaining moisture.

A2.3 Unless otherwise agreed with the

purchaser, testing shall be conducted on 10%(minimum of one piece) of each valve type,

class, and size contained on the purchase order.

A2.4 All instruments (flow meters, pressuregauges, torque wrenches, etc.) shall be

calibrated. Helium sniffing devices shall be

calibrated as per the instrument manufacturers

recommendation.

A3. TEST EQUIPMENT

A3.1 The valve to be tested to Section A1.1

requirements shall be supported in an

insulated stainless steel tank. The ends of the

valve shall be blanked off with stainless steel

blank flanges, plugs, or plates, to contain

pressure during the test. Small diameter 18-8

or copper tubing shall be connected to each

end of the valve. Tank, flange, plugs, plates,

and fittings used for testing shall be 18-8

austenitic stainless steel compatible with

liquid nitrogen at -320 F (-195 C).

Similar requirements apply for valves tested to

Section A1.2 requirements except materialsfor flanges, plugs, tubing or plates may be

made of a material meeting the test

temperature requirements.

During testing, gate, globe, ball and butterfly

stem orientation shall be vertical. Check

valves (piston, ball, swing, dual plate, etc.)

may be tested in either vertical or horizontal

disc position except for gravity closure check

valves, which shall be tested in a vertical disc

position.

A3.2 At least one (1) thermocouple shall be

attached to the valve body. A second

thermocouple shall be attached to the valve

packing area. A third thermocouple shall be

attached to the outlet of the pressure tubing.

The packing and pressure tubing

thermocouples should be insulated from

direct exposure to the liquid nitrogen to avoid

false readings. See Figure A1 for typical test

set-up.

A4. PURGING

A4.1 Gate and globe valves shall be partially

opened and ball and butterfly valves shall be

fully opened prior to immersion in liquid

nitrogen per Section A1.1 or other media per

Section A1.2.

ANNEX A

Low Temperature Cryogenic Testing



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A4.2 A helium low pressure (15 psig min.)

(1 barg min.) shall be maintained in the valve

during immersion with a purge started as cool-

down progresses.

A4.3 The valve shall be lowered into an

insulated tank and liquid nitrogen, per SectionA1.1 or other media per Section A1.2, shall be

allowed to fill the insulated tank around the

valve, to a level approximately 1 in. (25.4

mm) above the body/bonnet bolting or

body/bonnet welded connection.

A4.4 After the valve has stabilized at the

test temperature, the helium purge shall be

turned off and the valve cycled open and

closed three (3) times.

A4.5 To safeguard against inaccurate

readings during testing, the helium purge flow

through the valve prior to subsequent

pressurization shall be verified to be zero.

A4.6 Low Pressure Seat Test

A4.6.1 The valve shall be pressurized with 80psig (5.5 barg) helium in the open position.

A4.6.2 The valve shall be closed for a

minimum of ten minutes to stabilize the test

pressure.

A4.6.3 The valve body and packing test

temperatures shall be recorded. The leaking

gas temperature shall be measured by testoutlet tubing thermocouple (see Section

A3.2) and recorded. After five minutes, the

detected leakage rate shall be recorded and

then converted to an actual leakage rate, as

applicable, by multiplying the detected

leakage rate by correcting factor in

accordance with the Boyle-Charles rule. This

calculation shall correct the measured leakage

to standard conditions of 14.7 psig

(1.01 barg) at 60 F (15.6 C).

Alternately, an electronic mass flow leakage

device may be used and when calibrated to

standard conditions the temperature need not

be recorded nor the correction factor be

applied. The standard conditions leak rateshall be recorded.

A4.6.4 The maximum allowable leakage

rates shall not exceed those as listed in

Table A1.

A4.6.5 Repeat the sequence described in

Sections A4.6.1 through A4.6.4 on each seat

for bi-directional valves.

A4.7 High Pressure Seat Test

A4.7.1 Following the low pressure seat test

and with valve in the open position, gradually

increase the helium pressure until the

pressure reaches 80 psig (5.5 barg), then

close the valve and continue pressurization

until the valve reaches the test pressure listed

in Table A2. The valve shall be closed for a

minimum of ten minutes to stabilize the

pressure.

A4.7.2 The valve body and packing helium

test temperatures shall be recorded. Theleaking gas temperature shall be measured by

test outlet tubing thermocouple (see Section

A3.2) and recorded. After five minutes, the

detected leakage rate shall be recorded and

then converted to an actual leakage rate, as

applicable, by multiplying the detected

leakage rate by a correction factor in

accordance with the Boyle-Charles rule. This

calculation shall correct the measured leakage

to standard conditions of 14.7 psig(1.01 barg) at 60 F (15.6 C).

Alternately an electronic mass flow leakage

device may be used and when calibrated to

standard conditions the temperature need not

be recorded nor the correction factor be

applied. The standard conditions leak rate

shall be recorded.

A4.7.3 The maximum allowable leakage

rates shall not exceed those listed in Table A1.

A4.7.4 Repeat the test sequence as

described in Sections A4.7.1 through A4.7.3

on each seat for bi-directional valves.

A4.8 Shell Test

A4.8.1 Shell test leakage shall be measured

with a sniffing device sensitive only to

helium.




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A4.8.2 Shell test shall be performed while

the valve is still at cryogenic temperatures

from previous seat testing.

A4.8.3 Valve shall be partially opened and

pressurized to a test pressure of 200 psig

(13.8 barg) minimum.

A4.8.4 After the shell pressure has

stabilized, the valve shall be lifted from the

liquid nitrogen for access by the helium-

sniffing device.

A4.8.5 Any sustained leakage in excess of

1 x 10-4 std cc/sec or 50 PPM (v) shall be

cause for rejection during a minimum 10

second sniffing duration.

A4.8.6 Packing leakage that can be

corrected by packing adjustment shall not because for rejection.

A4.9 Ambient Low Pressure Seat Test

A4.9.1 Remove valve from test apparatus

and allow valve to warm up to ambient

temperature.

A4.9.2 Perform a low pressure seat test

using 80 psig (5.5 barg) nitrogen gas. Repeat

test on opposite seat for bi-directional valves.

A4.9.3 Acceptable leakage rate shall be inaccordance with parent valve testing standard.

A4.10 Ambient Shell Test

A4.10.1 With the valve half open, and portssealed, pressurize the valve with 200 psig

(13.8 barg) helium or other inert gas.

A4.10.2 Shell test pressure shall be

maintained for ten minutes.

A4.10.3 When utilizing a sniffing device,

which is sensitive only to helium, the entire

body, bonnet and gasket area shall be

examined.

A4.10.4 At any time during the test, a

sustained reading of greater than 1 x 10-4std

cc/sec or 50 PPM (v) shall be cause for

rejection during a minimum 10 second

sniffing duration.

A4.10.5 When testing with an inert gas,

each valve shell shall be subjected to a 200

psig (13.8 barg) pressure test for a minimum

duration of 10 minutes. No visible bubble

leakage is allowed through the pressure

boundary as determined by testing under

water, or with an applied foaming solution.

A4.10.6 If the stem packing shows signs of

leakage and requires adjustment, the pressure

shall be bled off, the packing tightened and

the valve re-pressurized for ten minutes

before resuming the test.

A5. CORRECTIVE ACTION

Valves, which fail to meet the test

requirements of this Annex, shall be

reviewed for root cause, corrective action

taken, and re-tested. Any corrective action

modifications made on the test valve shall

also be made on the balance of valves

represented by the test valve.

A6. TEST REPORT

The test report shall include the valve

information, testers name, and date of test,

temperatures, pressures, and durations.

Pressure-temperature charts shall be

provided, as required by a purchase order.



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TABLE A1

Allowable Helium Seat Leakage Rates

for Cryogenic Closure Tests

Seat Test

Allowable Leakage

(scc/minute/NPS)

Gate, Globe,

Butterfly, BallCheck

Soft

Seat

Metal

Seat

Low pressure seatTest (80 psig)

25 50 100

High pressure

Seat test for Class 150,

300 & 600 (Table A2)

75 150 300

High pressure seat

Test for Class 800, 900& 1500 (Table A2)

100 200 400

TABLE A2

Helium Test Pressures

Class Size*

High pressure

Seat Test**

(psig) (barg)

150 < NPS 24 230 15.8

300 < NPS 24 600 41.4

600 < NPS 18 1200 82.7

800 < NPS 8 1600 110.3

900 < NPS 8 1800 124.1

1500 < NPS 6 1800 124.1

*Test pressures for larger size valves shallbe limited to 300 psig (20 barg).

**Test pressures for butt-weld valves tested

with a test fixture, shall be limited to 200

psig (14 barg).

FIGURE A1Typical Test Set-Up



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15

ANNEX B

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; ASME/ANSI

B16.34-2009 Valves Flanged, Threaded, and Welding End; w/ Supplement (2010)B31.3-2010 Process Piping

BPVC-VIII, Div. 1-2010 Boiler and Pressure Vessel Code, Section VIII, Division 1, Rules for

Construction of Pressure Vessels; w/ Addenda Reprint (2011)

API; ANSI/API

6D-2008 (ISO 14313:2007) Specification for Pipeline Valves; w/ Addendum 1 (2009) and Addendum 2

(2011), Errata 1 (2008), Errata 2 (2008), Errata 3 (2009), Errata 4 (2010),

Errata 5 (2010), and Errata 6 (2011) (Identical to ISO 14313:2007, Petroleum

and Natural Gas Industries Pipeline Transportation Systems)600-2009 Steel Gate Valves Flanged and Butt-welding Ends, Bolted Bonnets;

w/ Errata 1 (2009)

602-2009 Steel Gate, Globe, and Check Valves for Sizes NPS 4 (DN 100) and Smaller

for the Petroleum and Natural Gas Industries

603-2007 Corrosion-resistant, Bolted Bonnet Gate Valves Flanged and Butt-welding Ends

608-2008 Metal Ball Valves Flanged, Threaded and Welding Ends

609-2009 Butterfly Valves: Double Flanged, Lug- and Wafer-type

MSS

SP-96-2011 Guidelines on Terminology for Valves and Fittings

The following organizations appear in the above list:

ANSI American National Standards Institute, Inc.

25 West 43rdStreet, Fourth Floor

New York, NY 10036-7406

ASME American Society of Mechanical Engineers (ASME International)

Three Park Avenue

New York, NY 10016-5990

API American Petroleum Institute

1220 L Street, NW

Washington, D.C. 20005-4070

ISO International Organization for Standardization

1, ch. de la Voie-Creuse, Case postal 56

CH-1211 Geneva 20, Switzerland

MSS Manufacturers Standardization Society of the Valve and Fittings Industry, Inc.

127 Park Street, NE

Vienna, VA 22180-4602




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16

APPENDIX X1

Guidance for Stem Strength Calculations

This Appendix is supplementary and does not include mandatory requirements.

X1.1 Valve Stems

X1.1.1 Gate and globe valve stems shall have an area and length to diameter (or radius of gyration) ratio that

precludes compression stress yield failure or elastic buckling while under compressive loading. Section 8.1

establishes a minimum extension length dimension that impacts on the stems length/diameter (or radius of

gyration) ratio.

X1.1.2 The following equations shall be used to determine the critical slenderness ratio of globe or gate

valve stems:

yS

CE

r

L 2= Equation #1

Or for round solid stems with r= d/4

yS

CE

d

L 2

4

= Equation #2

Where:

L/r = slenderness ratio for stems made from various stem cross section geometries,L/d = slenderness ratio for stems made from round bar,

L = unsupported length of a uniformly straight stem span between the upper stem guide and

stem-to-disc interface (see Figures 1 and 2),

d = stem diameter,

r =minimum radius of gyration for stem cross section, where AIr /= ,

E = modulus of elasticity of the stem material,

Sy = yield strength of stem material,

I = minimum moment of inertia about axis of bending through stems transverse areacentroid,

A = area of stems traverse area,C = constant depending on the valve stem end support conditions.

Suggested C= 2 for a stem of a globe or gate valve that has a stem guided disc/gate.

Suggested C= 4 for a stem of a globe or gate valve that has a body guided disc/gate.

Other Cs may be used at manufacturers option if representative of the design of their stem end

supports.



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APPENDIX X1 (continued)


X1.1.3 Using the physical dimensions of the stem intended to be used in the globe or gate valve the stems

actual L/r or L/d ratio shall be determined. The actual ratio shall be compared with that determined by

calculation from Equation #1 or Equation #2. If the actual stem L/r or L/d ratio is greater than that

determined by Equation #1 or Equation #2 the potential failure mode is buckling. Use the methods inSection X1.1.4.1 to calculate the critical load and safe load requirements. If the actual stem L/ror L/dratio

is less than that determined by Equation #1 or Equation #2, the potential failure mode is combined

compression/buckling. Use the methods in Section X1.1.4.2 to calculate the critical load and safe load

requirements.

X1.1.4 Critical and Safe Load Calculations

X1.1.4.1 If the stems actualL/dor L/ris greater than that calculated by Equation #1 or Equation #2 the

stems failure mode would be buckling. The stems critical load to cause buckling and safe operating

closing force shall be calculated using Equation #3 and Equation #4:

( )22

/ rL

EAC

Fc

= Equation #3 (Eulers Equation)

Or for round solid stems with r= d/4

2

2

)/(16 dL

EACF

c

= Equation #4 (Eulers Equation for Round Stems)

Where:

Fc = critical load to cause buckling.

Other symbols are as defined in Section X1.1.2.

The Safe Stem Load shall incorporate a factor of safety and be calculated as follows:

N

FF cS = Equation #5

Where:

Fs = safe stem force,

Fc = critical load to cause buckling as determined from Equation #3 or Equation #4,

N = factor of safety, commonly used = 2.

If the actual closing stem force is less than the critical as determined by Equations #3 or Equation #4 the stemwill be acceptable for use and not expected to fail by buckling, but an appropriate factor of safety shall be

applied by Equation #5 to insure a safe load determination. If the actual stem load is greater than the criticalload (Fc), than the stems cross sectional dimensions shall be increased. Equation #3 or Equation #4 can be

used to determine the stem required cross section dimensions.

Stem dimensional changes will change the stems L/r or L/d ratio, which may move the critical load (Fc)

calculations to the Section X1.1.4.2 method.




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18



X1.1.4.2 If the stems actualL/rorL/dratio is less than that calculated from Equation #1 or Equation #2

the stem stress failure mode would be based on combined compression/buckling. The stems critical load

and safe operating closing force shall be calculated using Equations #6 or #7 and #8:

( )

=

EC

rLSASF

y

ycr 2

2

4

/1

Equation #6 (J. B. Johnson Formulae)

Or for round solid stems

( )

=

EC

dLSASF

y

ycr 2

2/4

1

Equation #7 (J.B. Johnson Formulae for Round Stems)

Where:

Fcr = critical load to cause combined compression/buckling stem failure,

Other symbols are as defined in Section X1.1.2.

The safe stem load shall be calculated as follows:

N

FF crs = Equation #8

Where:

Fs = safe stem force,

N = factor of safety, commonly used = 2.

If the actual closing stem force is less than the safe stem force determined by Equation #6 or Equation #7 the

stem will be acceptable for use and not expected to fail by combined compression/buckling stress. If the actual

stem load is greater than the critical load (Fc) than the stems cross sectional dimensions shall be increased.

Equation #6 or Equation #7 can be used to determine the stem required cross section dimensions. Increased

stem dimensional changes will change the stems L/ror L/dratio, but for moderate length stems, the method

of Section X1.1.4.2 can be used to validate final stem design.

X1.1.4.3 For stem unsupported spans that fit other column end restraint models, the manufacturer may

developL/rorL/dequations for determination of the critical load and safe load incorporating a suggested

factor of safety (N) equal to two (2). For stems not of uniform diameter, the manufacturer shall execute

more extensive calculations or tests to assure that stem buckling or combined compression/buckling is

prevented.

X1.1.5 Extended stems in quarter-turn valves shall be proportioned so that, under torsional loading, the stem

torque is limited by the stem angle of twist and as a result also limited by the critical shear stress of the stem

material. Stem diameters and stem lengths shall be proportioned such that maximum applied torque meets the

requirements of Sections X1.1.6 and X1.1.7.



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X1.1.6 Quarter-turn valve stem length and diameter combinations that limit stem torsional deflection or

angle of twist to /90 radians (2-degrees) as determined by the following equation:

90 = GJ

TL Equation #9

Where:

= angle of twist, radians,

T = maximum stem design torque,

L = length of stem from point of torque application to obturator attachment (see Figures 3 and 4),

G = modulus of rigidity = E/2(1+),

E = modulus of elasticity of the stem material,

= Poissons ratio,

J = polar moment of inertia of round stem.

X1.1.7 The stem torque shall not be greater than that which could cause the stem material to exceed its

shear stress limit at the outer fiber as calculated by the following:

N

dT SS

16

max

3

Equation #10 (for Solid Round Stem)

Where:

Ts = the manufacturers designated maximum stem torque,

max = the stem material shear stress limit,

ds = the stem diameter,N = 2, a factor of safety.

X1.1.8 Valves with soft seats or a soft closing member insert to be used with flammable vapors or liquids

shall be designed in such a way that there is electric continuity between the body and stem of the valve. Such

a design must be qualified by testing the maximum electrical resistance, which shall not exceed 10 ohms

across the discharge path. To test for continuity, a new dry valve shall be cycled at least five times, and the

resistance measured using a DC power source not exceeding 12 volts.

X1.1.9 Valves in flammable fluid service shall be of fire-safe design, and in case the valve is equipped with

soft-seats or a soft-closing member, the design shall be successfully fire tested as per API 607, Fire Test for

Quarter-turn Valves and Valves Equipped with Nonmetallic Seats.



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Listing of MSS Standard Practices (as of May, 2012)TITLESP-6-2012 Standard Finishes for Contact Faces of Pipe Flanges and Connecting-End Flanges of Valves and Fittings

SP-9-2008 Spot Facing for Bronze, Iron and Steel FlangesSP-25-2008 Standard Marking System for Valves, Fittings, Flanges, and UnionsSP-42-2009 Corrosion Resistant Gate, Globe, Angle and Check Valves with Flanged and Butt Weld Ends (Classes 150, 300 & 600)SP-43-2008 Wrought and Fabricated Butt-Welding Fittings for Low Pressure, Corrosion Resistant Applications (Incl. 2010 Errata Sheet)

SP-44-2010 Steel Pipeline Flanges (incl. 2011 Errata Sheet)SP-45-2003 (R 2008) Bypass and Drain ConnectionsSP-51-2012 Class 150LW Corrosion Resistant Flanges and Cast Flanged Fittings

SP-53-1999 (R 2007) Quality Standard for Steel Castings and Forgings for Valves, Flanges, and Fittings and Other Piping Components Magnetic ParticleExamination Method

SP-54-1999 (R 2007) Quality Standard for Steel Castings and Forgings for Valves, Flanges, and Fittings and Other Piping Components Radiographic Examination MethodSP-55-2011 Quality Standard for Steel Castings for Valves, Flanges, Fittings, and Other Piping Components Visual Method for Evaluation of

Surface Irregularities (ANSI-approved American National Standard)SP-58-2009 Pipe Hangers and Supports Materials, Design, Manufacture, Selection, Application, and Installation (incorporates content of SP-69, 77, 89, and 90)

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SP-60-2012 Connecting Flange Joints between Tapping Sleeves and Tapping ValvesSP-61-2009 Pressure Testing of ValvesSP-65-2012 High Pressure Chemical Industry Flanges and Threaded Stubs for Use with Lens Gaskets

SP-67-2011 Butterfly ValvesSP-68-2011 High Pressure Butterfly Valves with Offset DesignSP-69-2003 Pipe Hangers and Supports Selection and Application (ANSI-approved American National Standard)

SP-70-2011 Gray Iron Gate Valves, Flanged and Threaded EndsSP-71-2011 Gray Iron Swing Check Valves, Flanged and Threaded EndsSP-72-2010a Ball Valves with Flanged or Butt-Welding Ends for General ServiceSP-75-2008 Specification for High-Test, Wrought, Butt-Welding Fittings

SP-78-2011 Gray Iron Plug Valves, Flanged and Threaded EndsSP-79-2011 Socket Welding Reducer Inserts

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SP-91-2009 Guidelines for Manual Operation of ValvesSP-92-2012 MSS Valve User Guide

SP-93-2008 Quality Standard for Steel Castings and Forgings for Valves, Flanges, Fittings, and Other Piping Components Liquid PenetrantExamination Method

SP-94-2008 Quality Standard for Ferritic and Martensitic Steel Castings for Valves, Flanges, Fittings, and Other Piping Components Ultrasonic

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SP-98-2012 Protective Coatings for the Interior of Valves, Hydrants, and FittingsSP-99-2010 Instrument Valves

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SP-110-2010 Ball Valves Threaded, Socket-Welding, Solder Joint, Grooved and Flared Ends (incl. 2010 Errata Sheet)SP-111-2012 Gray-Iron and Ductile-Iron Tapping SleevesSP-112-2010 Quality Standard for Evaluation of Cast Surface Finishes Visual and Tactile Method. This SP must be used with a 10-surface, three dimensional Cast

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SP-114-2007 Corrosion Resistant Pipe Fittings Threaded and Socket Welding Class 150 and 1000 (ANSI-approved American National Standard)SP-115-2010 Excess Flow Valves, 1 NPS and Smaller, for Fuel Gas ServiceSP-116-2011 Service-Line Valves and Fittings for Drinking Water SystemsSP-117-2011 Bellows Seals for Globe and Gate ValvesSP-118-2007 Compact Steel Globe & Check Valves Flanged, Flangeless, Threaded & Welding Ends (Chemical & Petroleum Refinery Service)

SP-119-2010 Factory-Made Wrought Belled End Pipe Fittings for Socket-WeldingSP-120-2011 Flexible Graphite Packing System for Rising Stem Valves Design Requirements

SP-121-2006 Qualification Testing Methods for Stem Packing for Rising Stem Steel ValvesSP-122-2012 Plastic Industrial Ball ValvesSP-123-1998 (R 2006) Non-Ferrous Threaded and Solder-Joint Unions for Use with Copper Water Tube

SP-124-2012 Fabricated Tapping SleevesSP-125-2010 Gray Iron and Ductile Iron In-Line, Spring-Loaded, Center-Guided Check Valves

SP-126-2007 Steel In-Line Spring-Assisted Center Guided Check ValvesSP-127-2001 Bracing for Piping Systems Seismic-Wind-Dynamic Design, Selection, Application

SP-128-2012 Ductile Iron Gate ValvesSP-129-2003 (R 2007) Copper-Nickel Socket-Welding Fittings and Unions

SP-130-2003 Bellows Seals for Instrument ValvesSP-131-2010 Metallic Manually Operated Gas Distribution ValvesSP-132-2010 Compression Packing Systems for Instrument Valves

SP-133-2010 Excess Flow Valves for Low Pressure Fuel Gas AppliancesSP-134-2012 Valves for Cryogenic Service, including Requirements for Body/Bonnet ExtensionsSP-135-2010 High Pressure Knife Gate ValvesSP-136-2007 Ductile Iron Swing Check Valves

SP-137-2007 Quality Standard for Positive Material Identification of Metal Valves, Flanges, Fittings, and Other Piping ComponentsSP-138-2009 Quality Standard Practice for Oxygen Cleaning of Valves & Fittings

SP-139-2010 Copper Alloy Gate, Globe, Angle, and Check Valves for Low Pressure/Low Temperature Plumbing ApplicationsSP-140-2012 Quality Standard Practice for Preparation of Valves and Fittings for Silicone-Free ServiceSP-141-2012 Multi-Turn and Check Valve ModificationsSP-142-2012 Excess Flow Valves for Fuel Gas Service, NPS 1 through 12

SP-143-2012 Live-Loaded Valve Stem Packing Systems

(R YEAR) I di ffi d P i Li A il bl U R MSS i ANSI di d A i N i l S d d d l

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