Dear Sirs, Please find enclosed the following documentsbis.org.in/sf/med/MED16-1212.pdf · Please find enclosed the following documents: Doc. No ... 0.3This Indian Standard also covers

Dear Sirs, Please find enclosed the following documents: Doc. No. TITLE

Doc: MED 16 (1211) Draft Indian Standard Liquefied petroleum gas (LPG) containers for

automotive use - Specification (first revision of IS 14899:2000) Doc: MED 16 (1212) Draft Indian Standard Valve fittings for compressed gas cylinders

exceeding liquefied petroleum gas (LPG) cylinders (third revision of IS 3224:2002)

Kindly examine the Draft Standard and forward your views stating any difficulties which you are likely to experience in your business or profession, if this is finally adopted. Last date for receipt of comments: 31 January 2013.

Comments, if any, may please be made in the format as given overleaf and e-mailed to the undersigned at the above address.

In case no comments are received or comments received are of editorial nature, you will kindly permit us to presume your approval for the above document as finalized. However, in case of comments of technical in nature are received then it may be finalized either in consultation with the Chairman, Sectional Committee or referred to the Sectional committee for further necessary action if so desired by the Chairman, Sectional Committee.

The document is also hosted on BIS website www.bis.org.in. Thanking you, Yours faithfully

(T.V. Singh) Scientist ‘F’ & Head (Mech Engg) Phone/Fax: 011-23232509 E-mail: [email protected] Encl: As above NOTE-WHERE PRINCIPAL AND ALTERNATE MEMBERS OF AN ORGANISATION ARE FROM THE SAME STATION, ONE COPY OF THE DOCUMENT IS SENT ONLY TO THE PRINCIPAL MEMBER WHO MAY KINDLY SHARE THIS WITH HIS ALTERNATE AS WELL.

Doc MED 16 (1212) December 2012

Page 1

Draft For Comments Only

Draft Standard Valve fittings for compressed gas cylinders excluding

liquefied petroleum gas (LPG) cylinders – Specification (Fourth Revision of IS 3244) ______________________________________________________________________________________ Not to be reproduced without the permission of Last date for receipt of BIS or used as a STANDARD comments is: 31 January 2013 ______________________________________________________________________________________ FOREWORD

Adoption clause to be added later.

0.1 Compressed gases supplied in cylinders are diverse in their chemical composition and properties. Some are oxidizers, some are flammables, some are inert, etc. Gases vary in degree of corrosiveness, toxicity and exist not only in pure state but also in variety of mixtures. Thus it becomes a primary safety requirement of the cylinder valve that it must be appropriate for the intended use. The intended use must be identified and the cylinder valve must incorporate proper pressure capacity as well as functional reliability for safe operation.

0.2 This standard was originally based on BS341 Part 1 'Valve fitting for compressed gas cylinders'. The fourth revision of this Indian Standard has been necessitated to incorporate amendments & to align the tests with ISO/DIS 10297 and also as a result of experience gained by the industry and consumer over the year. While preparing this standard considerable assistance has been taken from ISO/DIS 10297

0.3This Indian Standard also covers the pin-index type valve for medical gas cylinders that were earlier covered under IS 3745. After the publication of this standard IS 3745 stands withdrawn.

0.4Major changes about in this revision are:

a) Description of different valves and application given in details. b) Oxygen pressure surge test, endurance test and flame impingement test added as type

test.

0.5Other standards for valve fitting are:

a) IS 7302:1974 Valve fittings for gas cylinder valves for use with breathing apparatus. b) IS 8737:1995 Valve fitting for use with liquefied petroleum gas (LPG) cylinders of

more than 5 litre water capacity - Specification (first revision) c) IS 8776:1988 Specification for valve fittings for use with liquefied petroleum gas

(LPG) cylinder up to and including 5 litre water capacity (first revision) d) IS 12300:1988 Specification for valve fittings for small freon cylinders

0.6 For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with 1S 2:1960 ‘Rules for rounding off numerical values (revised)’. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard


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1 SCOPE

1.1General This Standard covers the requirements for design, materials, manufacture and testing of new valve fittings for use with refillable aluminum and steel cylinders for compressed gases (permanent and high and low pressure liquefiable and dissolved gases) other than liquefied petroleum gas (LPG). The standard also covers valve fittings for use in fire fighting and for compressed natural gas cylinders for automotive use. It also covers the Pin-index type valve for medical gas cylinders.

1.2 This standard is applicable to valve fittings to be fitted to industrial and medical gas cylinders up to 1000 litre capacity, intended to convey compressed, liquefied or dissolved gases.

1.3 Exclusions This standard is not applicable to valves for breathing equipment, SCUBA (Self contained underwater breathing apparatus), cryogenic equipment or valve for small Refrigerant cylinders. The Residual Pressure Valve (RPV) is also not covered in this standard.

2 REFERENCES

The standards listed in Annex A are necessary adjuncts to this standard. At the time of publication, the editions indicated were valid. All standards are subject to revisions and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated in Annex A.

3 TERMINOLOGY For the purpose of this standard, the following definitions in addition to those given in IS 7241 shall apply. 3.1 Ageing A change in a metal by which its structure recovers from an unstable condition produced by quenching or cold working. 3.2 Bursting Disc An operating part of a safety device in the form of a disc, usually of metal and which is so held as to close the safety device channel under normal conditions. The disc is intended to burst at a predetermined pressure to permit the escape of gas. 3.3 Rated Bursting Pressure The maximum pressure at which the burst disc is designed to burst at the rated temperature when in contact with the pressure opening for which it was designed.


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3.4 Burst Test Pressure (Pvbt) Minimum pressure applied to a valve through a liquid medium during burst pressure test. 3.5 Combination Bursting Disc and Fusible Plug A bursting disc in combination with a low melting point fusible metal intended to prevent the disc bursting at its predetermined bursting pressure unless the temperature is also high enough to cause yielding or melting of the fusible metal. 3.6 Cylinder Neck The part of the cylinder that has the threaded connection for the valve stem. 3.7 Cylinder Valve Mechanical device attached to a compressed gas cylinder that permits flow into or out of the cylinder when the device is in the open position and prevents flow when in the closed position. 3.8 Diaphragm(s) Formed, flexible disk(s) clamped between the valve gland/bonnet and the ledge in the valve body in diaphragm-type valves that provide(s) a seal or pressure barrier between the wetted parts of the valve and the exterior. 3.9 Dip Tube (Siphon Tube) (also known as ‘Eductor Tube) Tube fitted to the valve to allow withdrawal of liquefied gas without inversion of the cylinder / Tube that is attached to the valve inlet to withdraw liquid or vapour from the cylinder. 3.10 Endurance Torque (Te) Closing torque used during the endurance test. 3.11 Endurance Torque at end (Te. end) Endurance torque achieved at the end of the endurance test. 3.12 Endurance Torque at start (Te. start) Endurance torque to be applied at the beginning of the endurance test. 3.13 Excess Flow Valve Valve designed to close when the flow rate of fluid passing through it exceeds a prescribed flow rate as determined by pressure drop. 3.14 External Leak Tightness Leak tightness to atmosphere (leakage in and/or leakage out) when the valve is open and the outlet is sealed.


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3.15 Failure Torque (Tf) Opening or closing torque (whichever is the lower value) to be applied to obtain the mechanical failure of the valve operating mechanism and/or valve operating device. 3.16 Filling Pressure The settled pressure at a uniform temperature of 15oC at full gas content. 3.17 Flow Rating Pressure The pressure at the inlet of the pressure relief device which is used for establishing its rated flow capacity. 3.18 Flow Restrictor Device designed to limit the maximum flow through the valve outlet. 3.19 Free Air or Free Gas Air or gas measured at a pressure of 1 atmosphere at 20o C. 3.20 Full Flow Valve’s open position when maximum flow capacity is achieved. 3.21 Fusible Plug An operating part in the form of plug filled with suitable unused low melting point material, usually a metal alloy, which closes the safety device channel under normal conditions and is intended to yield or melt at a predetermined temperature to permit the escape of gas. 3.22 Gland Nut (also known as ‘Packing Nut’ or ‘Bonnet’) Threaded valve component tightened onto or into the valve body to retain and compress the packing, diaphragm(s) or other sealing member(s). 3.23 Hand Wheel Manually operated device attached to the valve spindle used to open and close the device. 3.24 Hand Wheel Diameter Nominal value of twice the largest radius from the centre of the hand wheel. 3.25 Internal Leak Tightness Leak tightness across the valve seat (leakage in and/or leakage out), when the valve is closed.


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3.26 Leak An unintended flow of gas or liquid in excess of 6cm3/h (at nominal condition 200C and 1013 mbar). 3.27 Bottom Spindle (also known as ‘Seat Insert Holder/Seat Plug/Lower Plug) Lower member of a two-piece spindle actuated by the top spindle. 3.28 Minimum Closing Torque (Tc) Torque necessary to be applied to a valve operating mechanism to obtain internal leak tightness. 3.29 Normalizing A process in which steel is heated to a temperature above its upper transformation temperature (known as solution temperature) and subsequently cooled in still air. 3.30 Outlet Dust Cap/Plug Cap or plug that only serves as a protective covering for the valve outlet to minimize contamination from external sources. 3.31 Outlet Seal Cap/Plug (also known as ‘Gas tight outlet seal cap/plug’) Cap or plug that serves as a protective covering for the valve outlet against contamination from external sources and serves as a pressure barrier to prevent leakage through the valve outlet. 3.32 Oversized Valve A valve having larger than normal stem thread to suit an oversized cylinder neck thread. 3.33 Over Torque (To) Maximum opening or closing torque (whichever is the lower value) applied to valve operating mechanism and valve operating device, which the valve can tolerate and remain operable. 3.34 Oxidizing Gas Service Valve Valves used for oxygen, oxygen enriched gas mixtures (over 23.5% oxygen) or other highly oxidizing gases such as nitrous oxide. NOTE - Valves used for air that has an oxygen concentration not greater than 23.5% by volume are not considered oxygen gas service valves. 3.35 Packing Non-metallic material installed around the spindle in a packed valve that when compressed creates a seal against leakage past the spindle.


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3.36 Packing Follower (also known as ‘Packing Gland’) Ring, usually metal, often installed on top of the packing in a packed-type valve so the packing nut is not torqued directly against the packing. 3.37 Packing Ring (also known as ‘Packing Collar’) Ring installed in a packed-type valve to provide a suitable seat for the packing. 3.38 Pin-indexed Non-threaded type of connection to the Valve outlet where non-interchangeability among connections is maintained by using a series of blind holes in the valve and matching pins in the connecting part. 3.39 Pressure Relief Device (PRD) Pressure and/or temperature activated device used to prevent the pressure in a normally charged cylinder from rising above a predetermined maximum, thereby preventing rupture of the cylinder. 3.40 Pressure Relief Nut Rupture disk holder threaded onto the valve body that incorporates a precisely machined edge around a relief device discharge port against which the disk is designed to rupture. 3.41 Pressure Relief Plug Rapture disk holder threaded into the valve body that retains a rapture disk in place and incorporates a precisely machined edge around a relief device discharge port against which the disk is designed to rapture. 3.42 Pressure Relief Valve A safety device containing an operating part that is held normally in a position closing the safety device channel by spring force and is intended to open and to close at predetermined pressures. 3.43 Prototype test (also known as ‘Design Qualification Test or Type Test) A test or series of tests directed towards approval of a design, conducted to qualify the cylinder valves to the requirements of the product specification carried out and valid for a given family of valves having the same basic design. 3.44 Quenching A process in which a material is heated to a temperature above its upper transformation temperature (known as solution temperature) and then quenched in a suitable medium. 3.45 Rated Flow Capacity The capacity of a pressure relief device measured in cubic metres per minute of free air at the designed flow rating pressure.


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3.46 Seat Insert Material contained in or on the bottom spindle (sometimes on a one-piece spindle) usually made of a soft material to facilitate sealing against the valve body seat. 3.47 Sealing Face The fixed contact face in the valve body for completing the seal against gas flow 3.48 Shutoff (also called ‘Closure’) Position of the Valve when the valve spindle is in contact with the valve body seat, no-flow condition of the valve. 3.49 Spindle The element(s) of the valve which, when operated, directly or indirectly actuates the sealing member (seal) to ‘open’ or ‘closed’ position. 3.50 Start–to –discharge Pressure The pressure at which the first bubble appears through water seal of not over 100 mm on the outlet of the pressure relief valve. 3.51 Stress Relieving A process to reduce internal stresses in a metal/forging/component by heating it to a suitable temperature for a stipulated period of time. 3.52 Tang Member or extension projecting from either the lower end of an top spindle or the upper end of a bottom spindle, mechanically attached or integral to the spindle, through which torque is transmitted in a two-piece spindle. 3.53 Thread Sealant Material supplied to a taper thread to effect a gas tight joint. It fills the cavity remaining in the helix of mating threads. 3.54 Thrust Bearing Disk-like part sometimes inserted between the top spindle and the metal diaphragms to reduce friction. 3.55 Toggle Usually a handle (lever) attach to the valve by pin to rotate the operating mechanism of the valve 3.56 Top spindle Upper member of a two-piece spindle that when operated causes the bottom spindle to move.


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3.57 Valve Actuator Manually or remotely operated device used to open and close the valve. 3.58 Valve Body The major valve component which includes an inlet and an outlet and, where applicable, a boss for the pressure relief device / Major portion of the Valve (normally one piece) that contains the orifice, Valve Body Seat, an inlet and outlet connections, and is machined to accept the component parts to create a valve assembly. 3.59 Valve Body Seat Sealing surface surrounding the orifice of the valve body. 3.60 Valve Inlet Portion of the Valve body that connects to the Cylinder / The inlet connection of the valve which fits on to the cylinder. 3.61 Valve Operating Device Component which actuates the Valve operating mechanism Example: Hand wheel, key, knob or actuator. 3.62 Valve Operating Mechanism Mechanism which closes and opens the valve orifice. Example: A threaded valve spindle which, when rotated, raises and lowers a seal. 3.63 Valve Outlet The service connection of the valve which is connected to the application device / Portion of the Valve body through which product is introduced or discharged 3.64 Valve Endurance Test Pressure(Pvet) Minimum pressure applied to valve through a gas during endurance test. 3.65 Working Pressure(Pw) Settled pressure (filling pressure) of a compressed gas (for permanent gas) at a uniform reference temperature of 15oC in a full gas cylinder for which the valve is intended. For liquefiable gases and dissolve gases, working pressure (Pw) shall at least the maximum developed pressure in a cylinder at a temperature of 65oC.


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3.66 Vapour/Liquid Valve (Twin Phase Valve) Valve designed so that either vapour or liquid may be discharged without inverting the container. 3.67 Yoke ‘Yoke’ is a type of connector attached to the Valve fitted with a pin or pins for outlet connection in pin-index valve.

4 CLASSIFICATION AND TYPES OF VALVES

4.1 Classification Standard valves can be classified based on their sealing arrangement and can be classified as per following basic designs:

a) Compression packed Gland Seal Valve or Packed Valves b) Pressure seal valve c) ‘O’ ring Gland Seal Valve d) Diaphragm Gland Seal Valve

Standard cylinder valves have either metallic sealing or non-metallic sealing. All the basic designs may be hand wheel or key operated. Apart from these, there are also following special type of cylinder valves such as

a) Ball type valve b) Quick Release valves c) Squeeze grip Type valve

4.2 Descriptions of Different Valves and Applications

4.2.1 Compression Packed Gland Seal Valve Packed valve refer to valve that use compressed packing to make a seal around the valve spindle and at the valve body. The basic parts of packed valves are valve body, spindle, gland nut and packing that is located between the gland nut or packing follower and packing ring. To ensure a good seal at the spindle, the gland nut must be firmly tightened to compress the packing against the spindle. These valves normally have metal to metal seating (Fig. 1) but may be used with soft seating – widely used for Chlorine valve, Ammonia valve, Sulphur dioxide valve, etc.

4.2.2 Pressure Seal Valve Pressure Seal Valves refer to valves that use an top spindle that is spring loaded upward against the packing, when the valve is in service; system pressure assists in creating a seal against leakage around the spindle. Pressure seal valve have generally non-rising stem (Fig. 2) – used for non-corrosive gas such as Oxygen, Nitrogen, Inert gas, etc.


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4.2.3 ‘O’-Ring Gland Seal Valve ‘O’ ring gland seal valve use one or more “O’ – rings to create a seal around the top spindle. The valves are normally having soft seating with two piece spindle construction and a non rising top spindle (Fig - 3). These valves have a wide range of pressure and gas applications – used for non-corrosive gas such as Oxygen, Nitrogen, Inert gas, etc.

4.2.4 Diaphragm Gland Seal Valve Diaphragm gland seal valve use diaphragm(s) rather than packing to seal the opening through which valve’s internal parts are installed. The gland nut, which threads into the valve body, clamps the outer edges of the diaphragm against a ledge in the valve body to form a seal. As the diaphragm seal provides high integrity protection both for external and internal leakage, these valves are used with hazardous, highly toxic, high pyropheric gases (Fig. 4). They are also used for high purity gases such as krypton, xenon etc.

4.2.5 Ball-Type Valve Ball type valve is on and off type valve. These valves use a polished ball inside the operating mechanism to open or close the gas passage (Fig. 5). It is not very uncommon for these valves to have dual outlet. Typical application is CNG valves for on board application.

4.2.6 Quick Release Valves These valves are used in closed condition for extended periods of time and are often only operated in emergency situations (for example fire fighting and avalanche airbag applications) . In most cases, the valves are only operated once or a few times and may be associated with manually, mechanically, electrically, thermally, hydraulically, or pneumatically operated device for opening the associated sealing system .

Valve type with one time actuation is shown in Fig. 6a for the purpose of completely discharging the pressure receptacle whose sealing system is destroyed by the actuation device when the valve is actuated. The sealing system must be replaced or reconditioned before the valve is used again.

Valves with multiple actuation is shown in Fig - 6b for multiple, if necessary intermittent, actuation for the purpose of completely or partly discharging the pressure receptacle whose sealing system is not destroyed by the actuation device when the valve is actuated.

4.2.7 Squeeze Grip Type Valve In this type of valve, pressure tends to keep the valve shut in a reverse seated valve. In a conventional cylinder valve where the spindle rises to open, pressure tends to keep the valve open. As the cylinder pressure decreases, the total force available to sustain valve shutoff also decreases. Shown in Fig - 7.


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Illustration of Typical compression packed gland seal valve

Fig-1

Illustration of Typical Pressure seal valve

Fig-2

Illustration of a Typical Diaphragm gland seal valve

Fig-4

Illustration of a Typical O-ring gland seal valve

Fig-3


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Fig-6a Illustration of a Typical Quick release valve-multiple actuation

Illustration of Typical Ball type valve

Fig-5

Illustration of a Typical Quick release valve-one time actuation

Fig-6b

Fig-7

Illustration of a Typical Squeeze grip type valve


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5 SUITABILITY OF MATERIALS

5.1 Material All materials used in the manufacture of valves, including gaskets, seats and protective coatings shall be compatible with the gas to be contained in the cylinder. For cylinder valves used with gas mixtures, the compatibility of the materials in contact with the gas with each component of the gas mixture should be considered. The material of the valve bodies shall comply with the material properties in 5.2, 5.3, 5.4 and 5.5.

5.2 Chemical Composition Recommended valve materials are given in Tables 1. The actual chemical composition shall be the subject of agreement between the purchaser and the manufacturer except for Chlorine and Boron Trifluoride Valves. 5.2.1 Material of construction for valve of Chlorine and Boron Trifluoride cylinders shall be as under. 5.2.1.1 Valve body 5.2.1.1.1 Aluminum silicon bronze Chemical composition: Copper : Remainder Lead : 0.05 %, Max Tin : 0.20%, Max Iron :0.30 %, Max Nickel :0.25 ‘%,Max Aluminium: 6.3 to 7.0 % Silicon :1.5 to 2.0% Manganese :0.10 %, Max Zinc : 0.50%, Max Arsenic :0.15 %, Max NOTE - For guidance IS6912 designation FABS may be referred Valve body forging shall be heat treated between 580°C and 607°C for 4 h and to be air cooled in open atmosphere. 5.2.1.2 Valve spindle Valve spindle shall be machined from wrought Nickel-Copper alloy. Typical composition of the alloy given hereunder is for guidance only: Ni: 63%, Min; Cu: 28 – 34%; Fe: I.0 to 2.5% Maximum admissible impurities AI: 0.5%, C: 0.16%, Mn: 1.25%, Si: 0.5%, S: 0 02%, Others: 0.1%


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5.2.1.3 Other Brass components Other brass components for example gland nut, gland packing, collar packing, outlet cap etc., shall be made from free cutting brass rods (see IS 319) or forging quality brass such as lead brass confirming to IS 6912 or from any other material approved by statutory authority.

5.2.2 Acetylene Valve if manufactured from Copper based alloys; the copper content shall not exceed 65% by weight 5.2.3 Copper and its alloy shall not be used in gas-wetted areas with ammonia due to stress corrosion cracking

5.2.4 Copper and its alloy shall not be used in gas-wetted areas with methylamine due to corrosive crack

5.2.5 Nickel shall not be used in gas-wetted areas with carbon monoxide due to formation of nickel carbonyl

5.2.6 The use of nickel in gas-wetted areas with hydrogen shall be carefully considered due to the potential for hydrogen embrittlement.

5.3 Mechanical Properties The material of the valve body shall comply with the requirements of mechanical properties given in 5.3.1 and 5.3.2. 5.3.1 Tensile Strength and Elongation The tensile strength and elongation of the material of the valve body determined according to IS 1608 shall be respectively at least 392 MPa (40 kgf/mm2) and 18 percent measured on a gauge length 5.65√So (So being the original area of cross-section). 5.3.2 Impact Strength The Izod impact strength of valve body determined according to IS 1598, shall not be less than 21.5J (2.2 kg.m) for brass, manganese bronze or aluminium bronze, aluminium silicon bronze and 54.7J (5.6 kg.m) for steel. 5.4 Test Samples Test samples for tensile and Izod impact tests shall, wherever practicable, be drawn from a valve body blank; where this is not practicable, the test samples shall be made from same raw material (wrought or extruded section), giving the same outside shape as the valve body blanks it represents. The scale of sampling and criteria for conformity shall be in accordance with the requirements of 11.12. 5.5 Protective Finishes Protective finishes and quoted components if used shall not adversely affect the performance of the valve or the materials of construction. All valves to be fitted with medical cylinders shall be bright chromium plated conforming to service condition 2 of table 3 given in IS 1068. Plating shall not be carried out on gas wetted areas to avoid the flaking or particle generation and on inlet and outlet threads.


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Table 1: Details of Valves (Clauses 5.2, 8.1.4 and 9.1.1) All dimensions in millimeters.

Gas

Name Chemical Symbol

Typical Valve Material

Designation of Screw Thread Outlet (Parallel Threads) 1)

Pitch Outlet No.

Width Across Flat of the Square of

Spindle

(1) (2) (3) (4) (5) (6) (7)

Acetylene C2H2 Non-ferrous or steel G 5/8-LH 1.814 2 7.1

Acetylene (marine lighting) C2H2 Non-ferrous or steel G 3/4-LH 1.814 1 8.0

Air Air* Non-ferrous or steel G 7/8A-RH 1.814 19 7.1

Ammonia NH3 Steel G 1/2A-RH 1.814 9 9.5

Argon Ar Non-ferrous or steel G 3/4A-RH 1.814 20 7.1

Bromochloro-difluoro methane CBrCIF2 Non-ferrous or steel EXT M22-RH 1.5 18 -

Bromofluoro methane CBRrF3 Non-ferrous or steel EXT M22-RH 1.5 18 -

Boron Trifluoride BF3 Non-ferrous G 5/8A-RH 1.814 5 9.5

Butadiene CH2CHCHCH2

Non-ferrous or steel G 5/8-LH 1.814 2 7.1

Carbon dioxide CO2 Non-ferrous or steel EXT W 21.8 X 1.814-RH

1.814 7 9.5

Carbon monoxide CO Non-ferrous or steel G 5/8-LH 1.814 2 7.1

Chlorine Cl2 Non-ferrous (see details in 5.2.1)

G 5/8A-RH 1.814 5 9.5

Chlorine Trifluoride ClF3 Steel G 5/8A-RH 1.814 5 9.5

Chloro difluoro methane CHCIF2 Non-ferrous or steel G 5/8A-RH 1.814 5 9.5

Chloro trifuluro methane CF3CI Non-ferrous or steel G 5/8A-RH 1.814 5 9.5

Coal gas Coal* Non-ferrous or steel G 5/8-LH 1.814 2 7.1

Compressed natural gas for automotive use for light duty vehicles.

CNG* Non-ferrous or steel G 5/8-LH 1.814 21 7.1

Compressed natural gas for automotive use for heavy duty vehicles.

CNG* Non-ferrous or steel INT.M12-RH 1.00 21A 5.0

Cynogen (CN)2 Non-ferrous or steel G 3/4A-LH 1.814 17 7.1

Dichloro-difluoro methane CCL2F2 Non-ferrous or steel G 5/8A-RH 1.814 5 9.5

Dichloro-fluoro methane CHFCL2 Non-ferrous or steel G 5/8A-RH 1.814 5 9.5

Dimethylamine (CH3)2NH Non-ferrous or steel G 5/8A-LH 1.814 6 9.5

Dimethyl ether CH3OCH3 Non-ferrous or steel G 5/8-LH 1.814 2 7.1

Ethylchloride C2H5CI Non-ferrous or steel G 5/8A-LH 1.814 6 9.5

Ethylamine C2H5NH2 Steel G 1/2A-LH 1.814 10 9.5

Ethylene C2H4 Non-ferrous or steel G 5/8-LH 1.814 2 7.1

Ethylene oxide C2H4O Non-ferrous or steel G 5/8A-LH 1.814 6 9.5 Table 1 Continued …..


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Gas

Name Chemical Symbol

Typical Valve Material

Designation of Screw Thread

Outlet (Parallel Threads) 1)

Pitch Outlet No.

Width Across Flat of the Square of Spindle 2)

(1) (2) (3) (4) (5) (6) (7)

Helium He Non-ferrous or steel G 3/4A-RH 1.814 20 7.1

Hydrogen H2 Non-ferrous or steel G 5/8-LH 1.814 2 7.1

Hydrogen chloride HCI Steel G 5/8A-RH 1.814 5 9.5

Hydrogen cyanide HCN Non-ferrous or steel G 3/4A-LH 1.814 17 7.1

Hydrogen fluoride HF Non-ferrous or steel G 5/8A-RH 1.814 5 0.5

Isobutylene (CH3)2C:CH2 Non-ferrous or steel G 5/8-LH 1.814 2 7.1

Krypton Kr Non-ferrous or steel G 3/4A-RH 1.814 20 7.1

Methane CH4 Non-ferrous or steel G 5/8-LH 1.814 2 7.1

Methyl bromide CH3Br Non-ferrous or steel G 1/4A-RH 1.337 15 7.1

Methyl chloride CH3CI Non-ferrous or steel G 5/8A-LH 1.814 6 9.5

Methylamine CH3NH2 Steel G 1/2A-LH 1.814 10 9.5

Neon Ne Non-ferrous or steel G 3/4A-RH 1.814 20 7.1

Nitrogen N2 Non-ferrous or steel G 3/4A-RH 1.814 20 7.1

Nitrous oxide N2O Non-ferrous or steel EXTW17.46 X 1.27-RH

1.270 12 6.0

Oxygen O2 Non-ferrous G 5/8-RH 1.814 3 7.1

Phosgene COCI2 Steel G 5/8A-RH 1.814 5 9.5

Sulphur dioxide SO2 Non-ferrous or steel G 1/2A-RH 1.814 11 9.5

Sulphur hexafluoride SF6 Non-ferrous or steel G 5/8A-RH 1.814 5 9.5

Trichlorofluoro methane CFCI3 Non-ferrous or steel G 5/8A-RH 1.814 5 9.5

Trimethylamine (CH3)3N Steel G 5/8-LH 1.814 6 9.5

Vinyl chloride C2H3CI Non-ferrous or steel G 5/8A-LH 1.814 6 9.5

Xenon Xe Non-ferrous or steel G 3/4A-RH 1.814 20 7.1

(*) Being mixture of gases does not have a Chemical symbol, but mentioned for identification. Notes: 1) The width across flat shall be applicable to the valve spindles when the valve is not provided with hand wheel but it is opened or closed with spanners or keys. In case the valve is provided with hand wheel or lever forming a part of the valve for opening/closing, the configuration of spindle shall be as per the manufacturer’s design. 2) For Pin-Index type, width across the flat of spindle, which is not to be square in shape, shall be 5.5 mm. (See Fig. 8a). In this standard, valve outlet threads are designated by using a combination of three terms. The first term indicates whether the thread is internal or external. The second term gives the thread profile and dimensions and the third term indicates whether it is a right-hand of left-hand thread. The second term has its first part the thread profile designation G, W or M standing for ‘Fastening pipe threads [see IS 2643 or ‘Whitworth’ or ‘1S0’ respectively. In the case of a fastening pipe thread to IS 2643, after the profile symbol G and the size designation, the symbol A indicates external threads of Class A. The absence of the symbol indicates internal threads. In case of other profiles, the nominal diameter and pitch in millimeters separated by ‘X’ are given 3) For gas mixtures, outlet no to be used on the valve shall be subject of agreement between the purchaser and manufacturer in consultation and approval of the statutory authority.


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6 VALVE DESIGN REQUIREMENT

6.1 General Criteria 6.1.1 Valve shall be designed to operate satisfactorily over a range of service temperature from –20 o C to + 65 o C in indoor and outdoor environment and shall be designed to operate under the extreme conditions of environment, which could cause a pressure rise in the cylinder contents up to maximum developed pressure. 6.1.2 Working pressure (Pw) of the valve shall be the maximum developed pressure in the cylinder at a temperature of 65oC in case of liquefiable gases or the filling pressure/settled pressure at 15oC in case of permanent gases (see IS 8775, IS 8866 and IS 8867). 6.1.3 The minimum finished wall thickness at any point of the valve shall not be less than 2.5 mm. However, this requirement shall be relaxed in case of sections not susceptible to tamper damage or rupture during use or where any damage to the section will not affect the sealing off of the valve. 6.1.4 The component and parts of the valve of same design of a manufacturer shall be interchangeable. 6.1.5 Dip (Siphon) tube and any other internal device such as filter arrangement, dust tube etc., shall be secured in a manner that will protect them from becoming loose or detached during transit and use.

6.2 Valve Dimensions 6.2.1 The Valve dimensions and connecting bore diameters shall be determined by the application of the gas, the rate of flow required, the gas service pressure, the required mechanical strength of the connections and any other safety aspects subject to agreement between the purchaser and the manufacturer. 6.2.2 The width across flat of the square of the spindle, for other than Pin-Index Valve, will be as per column 7 of Table 1. 6.2.3 Valve body dimension of Pin-Index Valve will be as per the fig. 8a, 8b, 8c and 8d, as applicable. 6.2.4 Valve Inlet details/dimensions shall be as per Section 8

6.2.5 Valves outlet detail/ dimension shall be as per section 9


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1) Applicable only if type safety is used. 2) Alternatively the yoke or the stabilizer shall be so dimensioned as to limit the rotation of the valve on the cylinder to 60 from vertical. 3) May be reduced to 3.5 mm, if clearance is provided for projecting safety plug.


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FIG. 8a Two-Pin System

1) Applicable only if type safety is used. 2) Alternatively the yoke or the stabilizer shall be so dimensioned as to limit the rotation of the Valve on the cylinder to 60 from vertical. 3) May be reduced to 3.5 mm, if clearance is provided for projecting safety plug.

Fig. 8b Single-Pin System


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1) Applicable only if type safety is used. 2) Alternatively the yoke or the stabilizer shall be so dimensioned as to limit the rotation of the valve on the cylinder to 60 from vertical. 3) May be reduced to 3.5 mm, if clearance is provided for projecting safety plug.

FIG. 8c First Alternative Design of Yoke type valve connection


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1) Applicable only if type safety is used. 2) Alternatively the yoke or the stabilizer shall be so dimensioned as to limit the rotation of the valve on the cylinder to 60 from vertical.

FIG. 8d Second Alternative Design of Yoke type valve connection


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6.3 Requirements for design of the connecting yoke: 6.3.1 Each small medical gas cylinder shall be fitted with a Pin-index yoke type valve with pin or pins in the yoke and hole or holes in the valve of the corresponding dimensions and position or positions for the gas in use for gas-tight seal. 6.3.2 A gas-tight seal shall only be possible when the pins in the yoke correspond to the holes in the valve. 6.3.3 The pins and yoke if do not correspond to the holes in the valve, a gas-tight seal shall not be possible and damage to the yoke or the valve shall be prevented. 6.3.4 Pins shall be fixed or assembled in such a manner that they cannot be removed by the user or become loose in service. 6.3.5 Sealing washer shall be a retained fit on the yoke spigot. 6.3.6 Use of more than one sealing washer is not permitted. 6.3.7 The yoke shall be able to resist, without permanent deformation, the load resulting from a torque 50 Nm applied to the valve clamping screw or locking device; and 6.3.8 The dimensions of the yoke shall limit the movement of the valve in the yoke to a maximum of 6o about long axis prior to pin engagement. (Note: ‘Yoke’ is not a part of the Valve but type of a connector attached to the Valve).

6.4 Valve operating mechanism: 6.4.1 All spindles shall close the valve by means of clockwise movement when viewed from the spindle end. 6.4.2 It shall be designed to permit the closure of the valve after exposure to a flame. (Ref: Flame Impingement test specified in 10.6) 6.4.3 It shall withstand over torque (To) without damage or failure of any component of the valve operating mechanism and/or valve operating device. At failure torque (Tf) no pressure retaining components shall have failed.

(a) For hand wheel operated valves with hand wheel diameter 65 mm or more the valve shall withstand a over torque (To) of 20 Nm without permanent deformation. The failure torque (Tf) shall not be less than 25 Nm (Refer excessive torque test specified in 10.3.4.2).

(b) For key operated valves, refer Table-15 for the over torque (To) and failure torque (Tf). The failure torque of the design will be agreed between purchaser and manufacturer and determined by excessive torque test as per 10.3.4.3


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6.4.4 It shall function satisfactorily after 2000 opening and closing cycles with Endurance torque (Te) at valve test pressure (Pvet) without replacement of the sealing system. Te is given in Table-15 and for some valve designs is allowed to be increased during the given cycles.

Note: This requirement is not applicable for Squeeze grip valves and quick release valves used for one time actuation. For special designs, the number of cycles shall be defined by the manufacturer on the basis of a specification from the customer or industry regarding the likely service conditions. The number of cycles shall be documented in the drawing.

The endurance test with relevant parameters is given in 10.5. 6.5 Safety: 6.5.1 The valve stem shall be of sufficient strength to stand valving torque (see 10.3.3). 6.5.2 Cylinder valves shall be capable to withstanding the Valve Burst test pressure (Pvbt) (see 10.3.1). 6.5.3 The valve shall be capable of withstanding an impact test (see 10.3.2). 6.5.4 The valves for Ammonia, Carbon Monoxide, Chlorine, Chlorine Trifluroide, Cyanogens Chloride, Fluorine, Hydrogen Sulphide, Methyl Bromide and Sulphur Dioxide shall be provided with a metallic security nut on the outlet to act as a secondary means of safeguard against the leakage of gas. The material of the security nut shall be compatible with the gas to be contained in the cylinder and also with the valve body material.

6.6 Leakage:

6.6.1 The internal leakage shall not exceed 6 cm3/h (at nominal conditions: 20oC and 1013 mbar) over the range of pressures and temperatures specified in the test, with the operating mechanism in the ‘closed’ position. (Ref: 10.4.3) 6.6.2 The external leakage shall not exceed 6 cm3/h (at nominal conditions: 20oC and 1013 mbar) over the range of pressures and temperatures specified in the test, with the operating mechanism in any position between and including the ‘fully open’ and the ‘closed’ positions. (Ref: 10.4.4) 6.7 Resistance to ignition: 6.7.1 Valves designed to be fitted to cylinders for oxygen, oxygen mixtures and nitrous oxide shall not ignite or show internal scorching damage when submitted to an oxygen pressure surge test. (Ref: 10.7)

7 PRESSURE RELIEF DEVICES 7.1 Design criteria of Pressure Relief Devices The materials, design and construction of a pressure relief device shall be such that it meets the following conditions. 7.1.1 There shall be no significant change in the function of the device and no detrimental corrosion or deterioration of the materials due to normal service conditions of the cylinder to which it is fitted.


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7.1.2 The breakage or failure of any internal component of the valve shall not obstruct free and full flow of the gas through the pressure relief device. 7.1.3 The material of construction shall be compatible with the gas (es) to be conveyed and other service conditions. 7.1.4 The design shall be such as to deter any unauthorized interference with the assembly and/or setting of the device. 7.1.5 The outlets from all pressure relief devices shall be so positioned that free discharge from the devices is not impaired. The discharge so coming out shall not come out as a single high velocity jet emerging radially to the axis of the cylinder to avoid injury to individuals working in that area. The yield temperature of the fusible plugs, if used with acetylene shall be between 98-104 oC and for compressed natural gas shall be 125 ± 10oC. 7.1.6 The minimum rated flow capacity of the pressure relief devices fitted to non-insulated cylinders having water capacity of 11 litre or more shall be as follows :

a) For permanent gases : Q 1 = 0.009 67Wc

Where, Q 1 is the rated flow capacity in cubic metres per minute of free air of 6 kgf/cm2 gauge pressure, and W c is the water capacity of the cylinder in litres.

b) For liquefiable gases: The rated flow capacity of the pressure relief devices shall be twice that given in item (a) above.

For cylinders having water capacities of less than 11 litre, the rated flow capacities shall be as given in (a) or (b) above, except that the value of W c shall be 11 litre that is, the rated flow capacity shall be 0.106 37 m3/min.

7.2 Relief / Bursting Pressure 7.2.1 Where the pressure relief device is a bursting disc fitted to the valves of seamless or welded cylinders, the maximum bursting pressure shall not exceed the test pressure of the cylinder and shall be more than the developed pressure of gas at 65oC. 7.2.2 Cylinders which are filled with CO2 shall be fitted with pressure relief devices. The bursting pressure range of the bursting discs fitted to carbon dioxide cylinders shall be 20 MPa (200 kg/cm2) to 22 MPa (220 kg/cm2) at room temperature. 7.2.3 Valves for cylinders for compressed natural gas (CNG) shall be provided with bursting disc or fusible plug or combination of both either in series or in parallel.


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7.2.4 Valve for Nitrous Oxide cylinder shall be provided with bursting disc.

7.3 Installation and Application of Pressure Relief Devices 7.3.1 Valves to be fitted to cylinders for a toxic gas shall not be fitted with a pressure relief device. 7.3.2 For any other valves, the PRD if required will be fitted in consultation with statutory authority.

7.3 Periodic Inspection

The PRD’s shall be subjected to periodic inspection by the user as required or during periodic inspection of the cylinder. 8 INLET CONNECTIONS: The Valve stem / cylinder neck will have either taper or parallel threads. The parallel threads will be applicable only for Aluminium cylinders.

8.1 TAPER SCREW THREADS ON THE VALVE STEM AND CYLINDER NECK The valve inlet shall be provided with any one of the types of taper screw thread Type 1, Type 2 or Type 4 as specified below:

Type 1 Thread – NGT threads, Taper 1:16 on diameter (see 8.1.1) Type 2 Thread – Taper 3:25 on diameter (see 8.1.2) Type 4 Thread – Taper 1:8 on diameter (see 8.1.3)

[Note: Type 3 threads with a taper of 6o included angle are covered in IS 8737]

8.1.1 Type 1 threads (Size 1, Size 2 and Size 3) with a Taper of 1 in 16 on diameter

The basic thread form, the principal dimensions and limits of crest and root truncation of the threads are shown in Figs. 9 (a) & 9 (b). Internal and External threads as shown in the drawing may be without undercut provided minimum length of full threads in the outlet drawing is as specified.

NOTE - This type of thread also conforms to thread size 1/2-14 NGT (termed as size 1), 3/4-14 NGT (termed as size 2) and 1-11 ½ NGT (termed as size 3) of ANSI/CSA/CGA Standard V-I-1987 ‘American National Standard for Compressed Gas Cylinder Valve Outlet and Inlet Connections’.

8.1.1.1 Limits on size For final inspection, limits on size (pitch diameter) of both external and internal thread are ±1 turn from basic, although the preferred working limits are ±1/2 turn from basic.

8.1.1.2 Limits on taper Should there be an unintentional difference in taper at the pitch elements of the valve and of the cylinder threads, it is preferred to have greater tightness at the bottom of the valve. In view of this requirement, the limits in gauging shall be as under:


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a) The taper on pitch elements of external threads shall be 1 in 16 on diameter with a minus tolerance of 1 turn but no plus tolerance in gauging.

b) The taper on pitch elements of internal threads shall be 1 in 16 on diameter with a plus tolerance of 1 turn but no minus tolerance in gauging.

8.1.1.3 The tolerance on 60° angle of thread shall be ±2°.

8.1.1.4 The tolerance on lead angle in the length of effective threads shall be ±0.076 2 mm valid for any size threaded to a thread length greater than 25.4 mm.

8.1.1.5 The maximum taper on pitch line per millimeter shall be 0.072 9 and minimum 0.057 3.

NOTE – Size 1 thread (1/2-14 NGT) is restricted for use with valve fittings for cylinders of 5 litre or more capacity and used with breathing apparatus or analgesic apparatus.

8.1.1.6 Size 1 and Size 2 threads shall be checked according to IS 15894.


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INTERNAL THREAD

EXTERNAL THREAD Fig.9 (a) Thread parameters and Limits on Crest and Root Truncation on different types of Taper Screw Thread

Table 3: Thread parameter for Type 1 Threads

Parameter

Thread size 1 and 2 i.e., ½ - 14 NGT and ¾ - 14 NGT

Thread size 3 i.e., 1 – 11½ NGT

p pitch 1.814 2.208 7

H

Height of sharp V thread

0.866 025 p 1.57122 1.913 2

h

Height of thread on product

0.800 025 p, Max 0.710 025 p, Min

1.451 1.288

1.767 1.568

f

Truncation on crest and root

0.033 p, Min 0.078 p, Max

Tolerance

0.059 87 0.141 51 0.081 64

0.072 88 0.172 28 0.099 4

F

Equivalent width of flat

0.038 p, Min 0.090 p, Max

Tolerance

0.068 94 0.163 29 0.094 35

0.083 93 0.198 78 0.114 85

All dimensions in millimeters


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Fig.9 (b) Limits on Crest and Root Truncation on different types of Taper Screw Thread Table 4: Dimensions for Type 1 Taper Threads on Valve Stems and in cylinder Necks

External threads (on Valve Stem) 3 Internal Threads (in Cylinder Neck)

Small End Full threads Large End Full threads

Thread Designation

Hand Tight

Engagement

L1

Major Dia

D0

Pitch Dia

E0

Chamfer-

45º X Min Dia

Pitch Dia

E8

Length

L8

Major Dia

D10 approx

Overall Length

L10 approx

Pitch Dia at Face

E1

Counter

90º X Max Dia

KK

Bore

Max

K3

Pitch

Dia

E3

Length

L1+L3

Length of Full Root

Min L9

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16)

Size 1

½-14 NGT

8.123 20.716 19.263 17.5 20.452 19.014 21.9 20.6 19.771 22.5 17.473 18.923 13.571 17.198

Size 2

¾-14 NGT

8.611 26.03 24.58 23 25.799 19.497 27.42 23 25.118 27 22.79 24.24 14.05 17.681

Size 3

1-11 ½

NGT

10.160 32.593 30.825 28.6 32.288 23.411 34.2 25.4 31.460 33.3 28.646 30.411 16.787 21.2

1) This thread size is restricted for use with valve fittings fitted to the cylinders of 5 litres or more water capacity used with breathing apparatus or with anesthetic or analgesic apparatus.

(All dimensions in millimeters)


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8.1.2 Type 2 threads with a taper of 3 in 25 on diameter and a nominal size 28.8 mm – the basic form, principal dimensions and their limits are given in Figs 10(a), 10(b) and Table 5

NOTE - This type of thread also conforms to thread size of 28.8 mm of DIN 477-1991 Sheet 1 ‘Specification of Gas Cylinder Valves – Types, Sizes, Connections, threads’ issued by the DIN Deutsche institut fur Normung. Also conforms to Type 25 T of BS 341 Part-1 1991.

Pitch-1.814mm, Angle-550, Taper-3 in 25 on Diameter Fig 10 (a) Basic thread form of Type 2 Thread, Right hand normal to Surface cone


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Nominal Diameter of

valve 1)

Valve Inlet Thread Thread in Cylinder Neck Length of Thread at Theoretical Thread

Dimensions

d +0.12

d1 +0.12

L1 d1 - 0.12

L2

Min L3 L4

28.8 28.8 25.8 26 27.8 22 8.33 17.67


Fig: 10 (b) Principal Dimensions for type 2 Taper Threads on Valve Stem and in Cylinder Neck.

Fig. 10 Whitworth Form Thread

8.1.2.1 Type 2 threads shall be inspected as per IS: 9122.

Table 5: Limits on principal Dimensions for Type 2 threads [Clauses 8.1.2, and Fig. 10 (a) and 10 (b)]


Diameter of Thread on Valve Stem Nominal Diameter Of Valve

Thread Element

At small end d1 At large end d

Diameter of Thread at Mouth of Cylinder Neck

Max Min Max Min Max Min

(1) (2) (3) (4) (5) (6) (7) (8)

Major dia 25.920 25.800 28.920 28.800 27.800 27.68

Pitch dia 24.759 24.639 27.759 27.639 26.639 26.519

28.8

Minor dia 23.598 23.478 26.598 26.478 25.478 25.358

8.1.3 Type 4 threads with a taper of 1 in 8 on diameter – There are three nominal sizes of these threads, namely 18.16 mm (Size 1), 25.4 mm (Size 2) and 31.75 mm (Size 3). The basic thread form, principal dimensions and their limits are given in Fig.11a & 11b and in Table 6 and Table 7 respectively.


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8.1.3.1 Type 4 threads shall be checked according to IS 7202.

Fig: 11a Basic Thread form of Type 4 thread on valve stem and in cylinder neck

Fig: 11 (b) Principle Dimensions for Type 4 taper thread, Right-Hand normal to surface cone.

Table 6: Principal Dimensions of Type 4 Taper Screw Threads on Valve Stems and in Cylinder Neck (Clause 8.1.3 and Fig. 11a & 11b)

All dimensions in millimeters.

Size Designation

Nominal Size of Valve

Taper on Diameter

Pitch Measured along the

Cone

Stem Major Dia

Length of Thread

Cylinder Neck Major Dia

Length of Engage-

ment

Length of Thread in Cylinder

Neck

A A Max B

C Min Min

D Min

(1) (2) (3) (4) (5) (6) (7) (8) (9)

Size 1 18.16 1:8 1.814 18.160 22.23 + 3.17

0 20.142 15.88 22.23

Size 2 25.40 1:8 1.814 25.400 25.40 + 3.17

0 27.788 19.05 25.40

Size 3 31.75 1:8 2.309 31.750 31.75 + 3.17

0 34.925 25.40 31.75


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Table 7: Limits for type 4 Taper Screw threads on Valve Stems and in Cylinder Necks (Clause 8.1.3 and Fig. 11a & 11b)


Size Designation

Nominal Size Of the Valve

Thread Element

Diameter of thread on Valve Stem at Small End

Diameter of Thread at mouth of Cylinder

A C Max Min Max Min

(1) (2) (3) (4) (5) (6) (7)

Major dia 18.160 17.958 20.414 20.142

Pitch dia 16.998 16.863 19.114 18.979 Size 1 18.16

Minor dia 15.834 15.563 18.019 17.816

Major dia 25.400 25.197 28.059 27.788

Pitch dia 24.237 24.102 26.759 26.624 Size 2 25.40

Minor dia 23.073 22.802 25.664 25.461

Major dia 31.750 31.483 35.281 34.025

Pitch dia 30.269 30.091 33.622 33.444 Size 3 31.75

Minor dia 28.788 28.433 32.230 31.963

8.2 Oversized Threads on Valve Stems 8.2.1 Type 1 Threads For valve fittings with Type 1 inlet threads on stem, the oversized dimensions are given in Table 8 read with Fig 9(a) and 9(b)

Table 8: Dimensions of Oversized Valve Inlets for Type 1 Inlet Threads [Clause 8.1.4.1 and Fig. 9 (a) and 9 (b)]

All dimensions in millimeters. Hand Tight engagement

External Threads (on Valve Stem) 3 Internal Threads (in Cylinder Neck)

Small end Full Threads Large end Full Threads Major

Dia Pitch Dia

Pitch Dia

Length Major Dia

Overall Length

Bore Max

Pitch Dia

Length of Full Root

Thread Designation

L1 D0 E0

Chamfer

45o x Min Dia

E8 L8 D10 Approx

L10

Approx

Pitch Dia at Face

E1

Counter 90o x

Max Dia

K3 E3

Length L1 +L3

Min L9

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) ¾ - 14 NGT

(Cl) – 1 8.611 26.030 24.580 23.0 26.081 24.031 27.8 28.5 25.118 27.0 22.789 24.239 14.054 24.031

¾ - 14 NGT (Cl) – 2

(4 turns oversize)

8.611 26.484 25.034 23.4 26.535 24.031 28.3 28.5 - - - - - -

¾ - 14 NGT (7 turns oversize)

8.611 26.824 25.374 23.7 26.875 24.031 28.6 28.5 - - - - - -

¾ - 14 NGT (Cl) – 3

(8.1/2 turns oversize)

8.611 26.995 25.545 23.8 27.046 24.031 28.8 28.5 - - - - - -

¾ - 14 NGT (Cl) – 4

(14 turns oversize)

8.611 27.817 26.167 24.6 27.668 24.031 29.4 28.5 - - - - - -

Notes: 1. For uses other than Chlorine, oversized threads for re-valving are generally specified at 4 turns [¾ - 14 NGT (Cl) – 2] and 7 turns oversize. For Chlorine, the ¾ - 14 NGT (Cl) – 1 size is standard, ¾ - 14 NGT (Cl) – 2 is 4 turns oversize, ¾ - 14 NGT (Cl) – 3 is 8.1/2 turns oversize and ¾ - 14 NGT (Cl) – 4 is 14 turns oversize.


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8.2.2 Type 4 Threads For valve fittings with type 4 inlet threads on stem, the oversize dimensions are given in Table 9 read with Fig 11 (a) and 11 (b)

Table 9: Dimensions of Oversized Valve Inlet for Type 4 Inlet Threads [Clause 8.1.4.2 and Fig 11 (a) and 11 (b)]

All dimensions are in millimeters

Size Designation

Nominal Size

Designation of Oversize

No. of turns Oversize

Stem Major Diameter

(A)

Taper on Diameter

Pitch Measured Along the

Cone

Length of Thread

(B+3.170)

(1) (2) (3) (4) (5) (6) (7) (8) 1st oversize 3.5 18.954 2nd oversize 7 19.747 3rd oversize 10.5 20.541

Size 1 18.16

4th oversize 14 21.334

1 in 8 1.814 22.23

1st oversize 3.5 26.194 2nd oversize 7 26.987 3rd oversize 10.5 27.781

Size 2 25.4


1 in 8 1.814 25.4

1st oversize 2.75 32.544 2nd oversize 5.5 33.337 3rd oversize 8.25 34.131

Size 3 31.75


1 in 8 2.309 31.75

8.3 Parallel Threads on the Valve stem with Cylinder Neck dimensions: The valve inlet shall be provided with any one of the following Parallel thread as specified below:

- M18 x 1.5 Metric Threads - M25 x 2.0 Metric Threads - 1.125” – 12 UNF Threads - ¾” – 16 UNF Threads - ¾” – 14 NPSM Threads (Also known as ¾” NGS threads)

The principal dimensions is shown in Fig. 12 read with Table 10 and the basic thread form of the threads are shown in Figs. 13 (a), 13 (b) & 13 (c).


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Cylinder & Valve neck dimension

Fig 12: Cylinder & Valve neck dimension

Table 10: Cylinder & Valve neck dimension [Clause 8.2.2 and Fig 12]

All dimensions are in millimeters


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Thread profile for Metric thread-External

Fig. 13 (a) – Thread profile for Metric thread-External Where d = Basic major diameter of external thread (Nominal diameter) d2 = Basic pitch diameter of external thread d1 = Basic minor diameter of external thread H = Height of fundamental triangle P = Pitch

Thread profile for NPSM thread-External

Fig: 13 (b) – Thread profile for NPSM thread-External

The following formula applies for calculating the basic dimensions: P = 25.4/n Where, n = Number of threads per the length (25.4 mm) H = 0.866025P hs = 0.64952P fcs = 0.10825P frs = 0.10825P Fcs = 0.12500P Frs = 0.12500P P = Pitch


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Thread profile for UNF thread-External

Fig: 13 (c) – Thread profile for UNF thread-External

9 OUTLET CONNECTION 9.1 There are broadly two types of Outlet connections a) Valve outlet having external and internal threads. b) Valves with Pin-index, Yoke type valve used exclusively for medical gas.

9.1.1 Valve outlet having external and internal threads 9.1.1.1 The dimension of the valve outlet having external and internal threads shall be in conformity with the details given in Table 7 and outlet numbers 1 to 21a. Internal and External threads as shown in the drawing may be without undercut provided minimum length of full threads in the outlet drawing is as specified. 9.1.1.2 Any hexagon with a left-hand thread on valve outlet and any hexagonal nut with a left-hand thread shall have notches on the corners for easy identification of the direction of thread.

9.1.1.3 The dimension for connectors, washers and nuts shall be in accordance with the details given for appropriate outlet. These connectors, washers, nuts are not part of the valve.


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9.1.2 Yoke type Connection (Pin-index Valves) used exclusively for medical gas

9.1.2.1 Basic dimension of yoke type valve connection The Yoke intended for fixing the housing apparatus to the valve shall conform to the dimensions given in Fig 8a (For Two-Pin system) and Fig 8b (For Single-Pin System) and first and second alternate design for yoke type Valve connections as shown in Fig 8c and 8d. 9.1.2.2 Dimensions and Positions of the Holes and Pins for Yoke type valve connections: The yoke shall be fitted with a pin or pins, the dimensions and positions of which correspond to the hole or holes in the valve as given in Fig 14 to 24 for different gases or gas mixtures.

a) Outlet connection for Oxygen (see Fig. 14) b) Outlet connection for Oxygen/Carbon Dioxide mixture (Carbon Dioxide ≤ 7 percent)

(see Fig. 15) c) Outlet connection for Oxygen/Helium Dioxide mixture (Helium ≤ 80 percent) (see

Fig16) d) Outlet connection for Ethylene (see Fig. 17) e) Outlet connection for Nitrous Oxide (see Fig.18) f) Outlet connection for Cyclo-Propane (see Fig. 19) g) Outlet connection for Helium/Oxygen mixture (Oxygen ≤ 20 percent) (see Fig. 20) h) Outlet connection for Carbon Dioxide/Oxygen mixture (Carbon Dioxide ≥ 7 percent)

(see Fig. 21) i) Outlet connection for Medical Air (see Fig. 22) j) Outlet connection for Special mixture of 50 percentage Nitrous Oxide and 50 percent

Oxygen (see Fig. 23) k) Outlet connection for Nitrogen (see Fig.24)

Fig 14: Outlet connection for Oxygen


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Fig 16: Outlet connection for Oxygen/ Helium Mixtures (Helium ≤80 Percent)

Fig 15: Outlet connection for Oxygen/Carbon Dioxide Mixtures (Carbon Dioxide ≤ 7 percent)


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Fig 18: Outlet connection for Nitrous Oxide

Fig 17: Outlet connection for Ethylene


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Fig 19: Outlet connection for Cyclo-Propane


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Fig 20: Outlet connection for Helium/ Oxygen Mixtures (Oxygen≤20 Percent)

Fig 21: Outlet connection for Carbon Dioxide/ Oxygen Mixtures (Carbon Dioxide≥7 Percent)


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Fig 22: Outlet connection for Medical Air

Fig 24: Outlet connection for Nitrogen

Fig 23: Outlet connection for Special Mixtures of 50 Percent Nitrous Oxide and 50 Percent Oxygen


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10 VALVE DESIGN QUALIFICATION TESTS (TYPE TESTS): Before valves are introduced into service, they shall be submitted for Design Qualification Tests (Type Testing). A Design Qualification Test is valid for a given family of valves with the same basic design. The number of test samples for testing a valve family to the specification of this standard shall be performed on valve samples as given in Table -11.

Material variants within a valve family, e.g. for reasons of compatibility between gas and non- metallic material require repetition of only the relevant parts of the type test, using a reduced number of test samples for the tightness and endurance test. Additional test samples might be required for changes or for material variants within the valve family (Refer Table-17).

When the valve drawing has been qualified to this standard and subsequent changes are made to the valve design, which could adversely affect valve performance will be reviewed and may require some qualification test(s) to be repeated (carried out again for requalification).

These changes can involve, but are not limited to modifications to the valve components (for example O-ring, packing, diaphragm, spindle, lubricant, material for valve body or characteristics (changes affecting flow path, inlet size or internal components).

Examples of changes that require retesting but are not limited to the following:

- Increase in valve working pressure will require repeat of valve burst pressure test, endurance test and oxygen pressure surge test (if applicable).

- A change in gas-wetted metallic or nonmetallic materials for an oxidizing gas service valve requires repeating the Oxygen Pressure Surge Test.

- Changes of the basic design dimensions of the valve components (e.g. inner spindle diameter, spindle thread pitch, seat diameter, dimension of o-ring(s), diaphragm thickness) repetition of tests to be decided case by case depending on the change

- Changes in the valve internal or external sealing system or change in gas wetted metallic or non metallic materials requires repeat of endurance test and oxygen pressure surge test (if applicable).

- Variations to outlet connections do not require further type testing.

- Additions to inlet connections (not qualified earlier) will require repeat of valve impact test and valving torque test.

- Changes in the valve body material may require repetition of any tests to be decided case by case depending on changes of chemical and mechanical properties.

-Changes in hand wheel diameter require repetition of endurance test and excessive torque test.

- Change in hand wheel material only require repeat of excessive torque test and flame impingement test in case of non metallic hand wheel.

- Changes in the valve operating mechanism require repetition of all tests except flame impingement test.

In addition to the tests listed in the examples, additional tests could be repeated depending upon the change in consultation with inspection authority

Unless otherwise stated, all tests shall be performed at room temperature.


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10.1 Drawing : Assembly drawing for a given valve family with same basic design shall include the following details:

(a) Design classification (b) Part list and material specification (c) Variants within a valve family (d) Valve working pressure (e) Lubricants, if used in the valve (f) Inlet sizes (g) Outlet sizes and gas services. (h) Minimum closing torque (Tc) (i) Endurance torque at start (Te. start) for metal to metal seat valve (j) Pressure relief device (PRD) details, if provided (k) In case valves are equipped with PRD- The maximum water capacity (Wc) for

permanent gas and liquefied gas for which the design is intended.

Table 11 Sequence of tests for type testing (no variants) (Clause 10.0)

Test sequence

Test and relevant sub clause

Condition of test valve

Test temperature

(0C)

Test pressure (bar)

Total no of sample to be

used

Test sample number

1 Hydraulic burst pressure test,

10.3.1

As received Room temperature

Pvbt 1 1

2 Excessive torque test, 10.3.4


-

4 7 to 10

3 Internal/External leak tightness,

10.4

As received valve to be conditioned

at 650C - 700C For 120-128 hours.

Room temperature

See Table-14

5

2 to 6

4 Endurance test, 10.5

From test sequence 3

Room temperature

Pvet 5 2 to 6


10.4


Room temperature

See Table-14 5

2 to 6


10.4


650C See Table-14 5

2 to 6


10.4


-200C See Table-14 5

2 to 6

8 Visual examination


Room temperature

- 5 2 to 6

9 Flame impingement test,

10.6


- 1 11

10 (if required)

Oxygen pressure surge test,

10.7

As received 600C +3 0C Pvet 3 12 to 14


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Pressure relief device test (for PRD equipped valves) 11

(if required) Flow capacity of

the PRD, 10.8


5.9 bar 3 15 to 18

Mechanical test (additional samples may be required as per increasing in category specified in Table-12) 12 Valve impact test,

10.3.2 As received Room

temperature - One for each

category As marked

13 Valving torque test, 10.3.3


- One for each category

As marked

10.2 Test Pressures 10.2.1 Valve Burst test pressure (Pvbt):

For compressed gases Pvbt = 1.5 x 1.5 Pw For liquefiable gases Pvbt = 1.5 x Pw For Dissolved gases Acetylene valve, Pvbt will be = 450 BAR

10.2.2 Valve endurance test pressure (Pvet): Pvet = 1.2 x Pw

10.3 MECHANICAL STRENGTH: 10.3.1 Valve Burst Pressure Test:

Valves equipped with pressure relief device shall be rendered inoperative for this test. The burst pressure test shall be carried out consecutively on one test sample in the following order.

a) The valve seat in closed position (valve outlet connection opened

b) The valve seat in open position (valve outlet connection(s) closed.

Water or another suitable liquid shall be used as test medium.

The hydraulic pressure shall be applied via the inlet connection and be raised continuously and gradually until a minimum of Pvbt is reached. The pressure shall be maintained for at least 2 min.

The test sample shall withstand the test without permanent visual deformation or burst.

Note- Special test requirement may be agreed between statutory authority and valve manufacturer for actuator operated valves.


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10.3.2 Resistance to Mechanical Impact: (Valve Impact Test)

The purpose of this test is to ensure that the valve has sufficient strength to withstand impact during transport, without release of contents.

One sample shall be tested from each category covered in the drawing to qualify all the other inlet sizes in that category. Valve designs that have a smaller bore size than the tested sample also are qualified in accordance with this test.

A hardened steel weight (a typical test rig shown in Fig 25) shall be dropped through a height so as to deliver impact energy in accordance with Table 12 at a minimum impact velocity of 3 m/s. This shall be achieved by allowing the weight to fall vertically.

Table-12 (Clause 10.3.2)

Category Thread size and respective

oversize Thread type Impact Values

(Joule)

Type 1 Size 1 I

Type 4 Size 1 Taper 80

Type 1 Size 2

Type 2 II

Type 4 Size 2

Taper 200

Type 1 Size 3 III

Type 4 Size 3 Taper 300

M18 x 1.5 mm

¾-16 UNF

M25 x 2.0

¾-14 NPSM

IV

1.125-12 UNF

Parallel 80

The point of impact shall be approximately two-thirds of the distance between the first exposed stem thread and the top of the valve body measured along the longitudinal axis of the valve.

The impact shall be in such a position that the blow from a 13 mm diameter steel ball is normal to the centerline of the valve and not cushioned by protrusions.

The valve shall not crack or shear. In addition the test sample shall remain operable by wheel/key/lever/actuator as appropriate.


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Fig 25: Typical Test Rig for Impact Test 10.3.3 Valving Torque Test: The purpose of the test is to ensure that the valve stem has adequate mechanical strength to prevent during valve installation. A rigidly anchored steel test rig/bung of the same inlet thread is to be used for this test.

For Taper threads, one sample shall be tested from each category covered in the drawing to qualify all the other inlet sizes in that category. Each parallel thread inlet shown in the drawing will be tested individually for qualification. Valve designs that have a smaller bore size than the tested sample also are qualified in accordance with this test.

Threads of the cylinder neck measured on the test rig and valve test sample shall be gauged to acceptance before carrying out the test.


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Use a calibrated torque system to tighten the test valve using compatible thread sealant/O-ring as used in service.

Table 13a gives the values of recommended valving torque for valves with taper stems and Table 13b gives the values of recommended valving torque for valves with parallel threads.

Value of tightening torque at 1.5 times the maximum shown in the Table 13a and Table 13b shall be used.

There shall be no sign of cracking or permanent deformation of the valve body or cracking of the valve stem. Deformation of the valve stem thread is acceptable.

Table 13a: Recommended Valving Torques for Taper Threaded Valve Stems (Clause 10.3.3)

Valving Torque

Steel Cylinders Up to 35 Bar Maximum Service Pressure

Steel Cylinders from 35 Bar to 300 Bar Maximum Service Pressure

Valve Material Category Valve Stem Size

Min. Nm Max. Nm Min. Nm Max. Nm

18.16 mm I ½-14 NGT 60 150 100 150

25.4 mm ¾-14 NGT II 28.8 mm

110 240 250 380

31.75 mm

Copper base alloy

III 1-111/2 110 240 250 380

18.16 mm I ½-14 NGT 135 150 135 150

25.4 mm ¾-14 NGT II 28.8 mm

340 380 340 380

31.75 mm

Carbon steel

III 1-111/2 340 380 340 380

25.4 mm ¾-14 NGT II 28.8 mm

120 135 340 380

31.75 mm

Stainless steel

III 1-111/2 120 135 340 380

Notes:

1. The torque figures given above are for use with PTFE thread sealant. If different sealant or pressure ranges are introduced, the torque figures given in the table may have to be changed to ensure a gas tight joint.

2. When torque figures have been specified for a particular valve by a manufacture of cylinder valves, the manufacturer’s torque values shall be applied in place of those specified in the above table.


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Table 13b: Recommended Valving Torque for Parallel Threaded Valve Stem for Aluminium Cylinders

(Clause 10.3.3) Valving Torque - Nm Valve Material Valve Stem Size Minimum Maximum

M18 x 1.5 mm 85 100

M25 x 2 mm 95 130

¾” – 16UNF 90 110

¾” – 14 NPSM 100 130

Copper base alloy, Carbon steel and Stainless steel

1.125” – 12 UNF 100 130 10.3.4 Excessive torque Test:

10.3.4.1 General The purpose of these tests is to check that the valve operating mechanism has adequate strength, and falls safely if subjected to excessive torque. This excessive torque tests are not applicable if an excessive torque cannot be applied e.g. for squeeze grip valves and most types of quick release valves.

10.3.4.2 For Hand-wheel operated valves

A total of 4(four) number of samples will be used for this test.

A closing torque on one test sample valve shall gradually be increased to a given To according to Table 15. At To the valve shall be able to work without noticeable difficulties. It shall not show any damage or failure of any component of the valve operating mechanism and/or valve operating device. This shall be checked by visual examination after dismantling the valve.

To determine Tf , a closing torque on a different test sample valve than used for the determination of To shall gradually be increased slowly until failure of any part of the valve operating mechanism or valve operating device occurs.

After this test, the valve operating mechanism may be severely damaged and not operable. No pressure retaining components shall have failed. Mechanical failure shall be in a manner that will not result in ejection of valve components.

This test shall then be repeated on two other test samples under the same conditions, but with applying an opening torque instead of a closing torque.

The value of Tf determined from applying a closing and an opening torque shall be not less than the value given in Table 15.

10.3.4.2 For Key/toggle operated valves:

A total of 4(four) number of samples will be used for this test.

For key/toggle operated valves Tf (Failure Torque) first shall be determined using two test samples.

To determine Tf a closing torque on one test sample and an opening torque on a second test sample shall gradually be increased slowly until failure of any part of the valve operating mechanism or operating device occurs. Measure the Torque values at the point of failure. The lowest value of these failure torques values will be taken as Tf.


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After this test, the valve operating mechanism may be severely damaged and not operable. No pressure retaining components shall have failed. Mechanical failure shall be in a manner that will not result in ejection of valve components.

Then To shall be calculated on the basis of the Tf using the equation given in Table 15. This value of To shall be applied on the other two other test samples not used for determination of Tf, in closing and opening direction respectively.

At To the valve shall be able to work without noticeable difficulties, it shall not show any damage or failure or any component of the valve operating mechanism and/or valve operating device. This shall be checked by visual examination after dismantling the valve.

10.4 Leak Tightness Test 10.4.1 General Minimum 5 (five) number of samples to be tested. Additional samples may be required to cover more than two variants within a valve family.

Table- 14 (Clause 10.4.1)

Pressures to be used for leak tightness test 0.5 bar 10 bar Minimum Pvet

The internal leakage shall be checked with operating mechanism in the closed position. The external leakage shall be checked with operating mechanism in any position between and including the ‘fully open’ and the ’closed’ positions. Internal and external leak tightness test shall be carried out at pressures given in Table-14 at temperatures specified in Table-11. 10.4.2 Leakage rate The internal and external leakage shall not exceed 6 cm3/h (at nominal condition: 20 0 C and 1013 mbar) over the range of pressure and temperature specified in the test. 10.4.3 Procedure for internal leakage

a. Seal valve outlet connection (s) b. Open the valve c. Apply the required pressure to the valve inlet d. Close the valve to the closing torque. For the leak tightness test carried out before the

Endurance test, the closing torque is Tc. For the leak tightness test carried out after the Endurance test, the closing torque required to achieve tightness shall not be greater than Te, end.

e. Open the valve outlet connection f. Wait at least 1 min before measuring the internal leakage rate. The internal leakage rate shall not exceed the rate specified in 10.4.2


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10.4.4 Procedure For external leakage

a. Seal valve outlet connection(s) b. Fully open the valve c. Apply the required pressure through the inlet d. Measure the leakage rate e. Also measure leakage rate with the valve operating mechanism in two further positions (approximately 2/3 and 1/3 of the ‘fully open’ position).

The external leakage rate shall not exceed the rate specified in 10.4.2

10.5 Endurance test: 10.5.1 Samples subjected to leak tightness test (10.4) shall be used in endurance test. Squeeze grip valves and quick release valves used for one time actuation shall be excluded from this test. Quick release valves designed for multiple actuations shall be tested for number of cycles and as per test parameters specified in the drawing.

All the samples for endurance test shall be preconditioned at 65+5/ -0 o C for 120+8 /-0 h.

An endurance test of 2000 opening and closing cycle with Te torque at Pvet shall be carried out. The valve inlet shall remain pressurized to Pvet throughout the test.

The description of the test equipment is given in diagram Fig 26. The valve outlet shall be connected to venting device that remains closed during the closing and opening position of the cycle. After each closure, the pressure downstream of the seat shall be released to atmosphere. There shall be a pause of at least 6 seconds at each fully opened and fully closed position. The average time taken shall be no more than 3 cycles per minute and no less than one cycle per minute for the duration of the test. No significant torque shall be applied in the fully open position.

Te is given in Table 15 and for metal to metal seal valve designs Te, start is allowed to be increased during the tests when internal tightness is no longer achieved. If the pressure measured at the high pressure transducer (Key no. 4 in Fig 26) after having vented the outlet and closing of venting valve (Key no. 5 in Fig 26) is more than 5 bar. Te, shall be increased by nominal 5% of the running torque but in any case not higher than Te end.

For the compression packed valves, if needed, adjustment of the packing nut is permitted according to manufacturer’s specification.

After completion of 2000 nos. of cycling, valve will be tested for leak tightness test (10.4) at room temperature, 65o C and -20o C at all specified pressures given in Table-14 and Te end shall not be exceeded. A visual examination shall be carried out to ensure that components such as diaphragm, hand wheel, ‘O’ rings, etc., are all in place and are functional. No sealing interface degradation such as tearing, ripping and particle accumulation shall be evident for metal to metal sealed cylinder valves for oxygen service.


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10.5.2 Typical arrangement of Endurance Test Equipment:

Key

1 D.C motor with torque transmitter 2 Test sample with adapter 3 Input test medium 4 High pressure transducer with display 5 venting valve 6 outlet 7 valve 8 inlet high pressure transducer with display for monitoring of pvt

a. In closed position: From pvt to atmospheric pressure. In open position pvt

b. In closed position: Sequence closed/open/closed. In open position: closed

Fig 26: Diagram of Typical arrangement of computer controlled test equipment.

10.5.2.1 Requirements of Machine and test cycle:

i. Speed and application of torque The test machine shall be able to open and close the test sample at a speed of between ten and thirty revolution per minute.

At the end of the closing part of the test cycle, drift in torque due to dynamic effects shall be no more than 10% of the set figure.

ii. Alignment: The test sample and the test machine spindle shall be aligned I such a way that no significant side or axial load is put on the valve during the test.

iii. Verification: Verification of the machine with regard to all test parameters to be controlled and measured such as torque. Pressure and temperature shall be carried out before commencing and after completion of


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each endurance test.

iv. Stroke of the endurance test: The test sample shall be cycled through its full stroke except that the spindle shall not get closer than 450 to the fully open position. This will ensure that the test machine does not apply torque in the fully open position.

v. Record: The test cycle shall be recorded automatically (e.g. as an illustration, see Fig 27).

Key a If the pressure variation is more than 10% of Pvet . Te has to be increased for some valve designs, see 10.5.

Fig 27: Diagram showing a typical cycle for the endurance test


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Table -15: Torques to be used for the Endurance test and Excessive Torque tests ( Clause 10.3.4.2)

Valve family as

given in 4.1 Internal Sealing system

Valve operating Device

Endurance Torque Te

(With a relative tolerance of ± 5%)

Over Torque

To

Failure Torque Tf

Hand wheel diameter D=65mm

7 Nm 20 Nm 25 Nm

Hand wheel of Other diameter

D x 7/65 Nm D x 20/65

Nm 1.25 x To

O – Ring gland seal valve,

Pressure seal valves and Ball

type Valve

Nonmetallic seal

Key/Toggle To / 3 Tf / 1.25 Tf Hand wheel

diameter D=65mm

Te.start = 7 Nm Te, end ≤1.5 x Te.start

20 Nm 25 Nm


Te.start = D x 7/65 Nm Te, end ≤ 1.5 x Te.start ≤16 Nm

D x 20/65 Nm

1.25 x To

Diaphragm gland seal valve,

compression packed gland seal valve and Ball type Valve

Nonmetallic seal

Key/Toggle Te.start = To /3

Te, end ≤ 1.5 x Te.start Tf / 1.25 Nm Tf

Hand wheel diameter D=65mm

Tc and Te.start are to be specified by the

manufacturer. But Te.start shall not less than

1.5 x Tc and not less than 7Nm

Te. end ≤ 1.5 x Te.start ≤16 Nm

20 Nm 25 Nm


Tc and Te.start are to be specified by the

manufacturer. But Te.start shall not less than

1.5 x Tc and not less than D x 7/65

Te. end ≤ 1.5 x Te.start ≤16 Nm

D x 20/65 Nm

1.25x To

O – Ring gland seal valve,

Diaphragm gland seal valve and compression packed gland

seal valve

Metal to Metal Seal

Key/Toggle

Tc to be specified by the manufacturer.

Te.start = Tc

Te, end ≤ To

Tf / 1.25 Nm Tf

Note: Standard industry practice is to apply a 7 Nm closing torque on commonly used 65 mm hand wheel diameter valves during operation. If the Hand wheel diameter is more than 65 mm, all parameter for 65 mm shall be applicable. 5 (five) different valve families/designs are covered by this Table. If the valve design is not covered by this table, the valve manufacturer shall specify the torques used and test parameters and include in the drawing.


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10.6 Flame Impingement Test This test is meant for non-metallic wheel/knob operated valves. Wheel operated valves with metallic hand wheel and non-metallic hand wheel operated valves equipped with metallic insert shall be excluded from this test.

1 (one) number of sample is to be tested.

The valve operating device of the test sample in the open position shall be exposed for 1 min. +0/-5 sec to an LPG blowpipe flame of 150mm length, such that the flame reaches a typical temperature of between 800o C and 1000o C and completely envelopes the operating device.

Although the valve operating device may be damaged during the test, it shall still be possible to close the valve manually after cooling.

10.7 Oxygen Pressure Surge Test

10.7.1 General

This test shall be carried out on valves to be used with cylinders for oxygen, oxygen mixtures and nitrous oxide. The purpose of the test is to check whether the valve can withstand Oxygen Pressure Surge safely.

3 (Three) new samples shall be tested.

Cylinder valves shall be tested via the valve connection used to fill the cylinder

10.7.2 Test installation requirements

Before testing the first sample, the ignition test installation shall be checked for the required pressure rise (for examples of test installation and pressure cycle specification, see Figures 28 and 29). For this purpose the test valve, at the end of the connecting tube, is replaced by a reliable pressure gauge. The maximum pressure at the dead end of the tube (measured by a suitable pressure indicating device and recorded) shall be achieved within 20 +0/-5 ms. The pressure rise time at the dead end of the tube shall be calculated from the time difference between where the pressure goes from 10 % of the first pressure peak to 90 % of the first pressure peak, see Figure 29. The first pressure peak shall not exceed 110 % of Pvet. NOTE - The actual pressure-time curve may exhibit a different wave form for each test laboratory. Stabilization time at Pvet is not fixed but shall be greater than or equal to 3 s. Before the next pressure surge the system (test sample and tube) shall be depressurized down to atmospheric pressure. Stabilization time at atmospheric pressure is not fixed but shall be greater than or equal to 3 s. The total time of the pressure cycle shall be 30 s, as illustrated in Figure 29. Total time is the time between the beginnings of two consecutive pressure surges. For calibration purposes, heated oxygen at (60 ± 3) °C shall be used.


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10.7.3 Test procedure Each test shall be carried out as follows: a) Supply oxygen at a temperature of (60 ± 3) °C, directly into the connection of the valve to be tested which shall be mounted in vertical position, by means of an oxygen compatible metallic tube having an internal diameter of 5 mm and a length of 1 m. The specified dimensions of the tube are essential in order to ensure that a well-defined energy input into the valve to be tested is achieved. b) Perform two test sequences in accordance with Table -16. The test valve should be at room temperature at the start of each sequence. Table-16

Test sequence Valve operating mechanism Connection to the cylinder 1 Closed Open 2 Open Sealed with a screwed metallic plug

c) The oxygen is heated to (60 ± 3) °C in the oxygen pre-heater. A quick opening valve (see Figure 28) controls the admittance of oxygen to the test sample. The test consists in subjecting the test sample to twenty pressure cycles from atmospheric to Pvet (see Figure 29). After the tests, the test sample shall be dismantled and carefully checked, including close visual examination of non-metallic components. The valve and its components shall not show any traces of ignition (e.g. notable surface deterioration including change in surface texture and/or colour, material loss) and no components shall be displaced (no longer in place where it was installed) due to testing, non-functional (e.g. broken) or missing.


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Fig 28: Example of an Oxygen pressure surge test installation

Key: 1. Inlet valve 2. Pre-heating device (e.g. water with electric heating) 3. Oxygen high-pressure vessel 4. Quick opening valve 5. Tube 6. Sample valve 7. Depressurization valve 8. Pressure gauge 9. Temperature 10. Actuator 11. Thermostat


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1 pressurization time measurement for each test cycle

2 first pressure peaks measured at start of each cycle

3 90% of 1st pressure peak

4 10% of 1st pressure peak

5 test cycle 1

6 test cycle 2

p pressure, in bar

t time, in s

Fig 29: Pressure cycle specification

10.8 FLOW CAPACITY OF THE PRESSURE RELIEF DEVICE (PRD)

3 (three) number of samples to be tested.

The purpose of the test is to measure the rated flow capacity of the Pressure Relief Device (PRD). In case parallel safety is provided both the PRD’s shall meet the minimum flow capacity requirement.

The manufacturer will specify the maximum water capacity (Wc), subject to the minimum of 11 litres capacity for which the valve is designed. The measured flow rate shall be equal to or more than the minimum flow capacity calculated for the corresponding water capacity.

The minimum flow capacity of PRD fitted to non insulated cylinder shall be calculated using the following formula:


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Sl. Requirement for different Type of gas a. For Permanent Gases:

Qa = 0.00967 Wc Where: Qa = rated flow capacity in cubic metres per minute of free air at 6 kgf/cm2 gauge pressure. Wc = Water capacity of the cylinder in litres.

b. For liquefiable gases: The rated flow capacity of PRD shall be twice of that given in (a) above.

Procedure:

a) The device shall be completely assembled from the inlet of the approach channel to the exit of the discharge channel in the manner normally assembled for use.

b) Each device shall be caused to operate either by pressure or temperature or by a combination of such effects and not exceeding either the maximum temperature or maximum pressure for which the device has been designed.

c) Without cleaning, removing parts, or reconditioning, each pressure relief device shall be subjected to an actual flow test wherein the amount of air released by the device is measured by flow measuring device.

d) Air or gas shall be supplied to the PRD through a supply pipe provided with a pressure gauge as close to the inlet of the valve as possible for recording the pressure.

e) The inlet pressure of the air or gas supplied to the safety device shall be not less than 7 kgf/cm2 (absolute)

f) Observations shall be made and recorded after steady flow conditions have been established. g) The rated flow capacity shall be the average flow capacity of devices tested, provided individual

flow capacity falls within 10% of the higher flow capacity recorded. Note: Ensure that there is no obstruction in flow line and the internal diameter for gas passage from the source cylinder to the valve inlet is greater than the largest orifice inside the flow passage of the valve from the valve inlet to the opening of the PRD.

10.9 Example of test sequence with variants

Table-17 gives an example of test sequence for one valve family (valve design) with two additional different o-ring material specifications as under.

a) O2 service - ethylene propylene (EPDM) b) CH4 service - fluorocarbon (FKM) c) Ar service - nitrile rubber (NBR)


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Table-17 - Sequence of tests for type test (basic valve design plus two material variant within the valve design) (Clause 10.9)

Test sequence as per table -15

Test and relevant sub clause

Total no of sample to be used

Test sample details with respect to variants

1 Hydraulic burst pressure test, 10.3.1

1 Sample with any O-ring material

2 Excessive torque test, 10.3.4

4 Samples with any O-ring material


10.4

4 Endurance test, 10.5


10.4


10.4


10.4

8 Visual examination

6 Two samples each with three different O-ring material

9 Flame impingement test, 10.6

1 Sample with any O-ring material

10 Oxygen pressure surge test, 10.7

3 Samples with EPDM O-ring material

11 Flow capacity of the PRD, 10.8

3 Samples with any O-ring material

12 Valve impact test, 10.3.2

One for each category Samples with any O-ring material

13 Valving torque test, 10.3.3

One for each category Samples with any O-ring material


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11 Pressure Relief Device (PRD) Test – Exclusive for CNG Valves:

11.1.1 Fusible Material – Resistance to extrusion test:

3 (Three) number of CNG valves to be selected at random and shall be tested with water at 30 MPa at room temperature for 30 min. The burst disc shall not be removed if present. During the test ,the fusible material shall not begin to extrude out of PRD

Increase the pressure at a rate of 0.5 MPa/s to 60 MPa or to the pressure at which the fusible material starts to extrude. During the test. The extrusion of the fusible material shall not begin at a pressure lower than 45 MPa.

11.1.2 Accelerated Life Testing: 11.1.2.1 General:

Fusible materials can creep and flow within the operating temperature range of natural gas vehicle PRDs. The test is to be performed to verify that the rate of creep is sufficiently low so that the device can perform reliably for at least one year at 82o C and for at least 20 years at 57o C. The test shall be performed on PRD design in which the fusible material is used i.e., in thermally activated PRD and Combination type PRD using Fusible plug.

11.1.2.2 Test procedure:

a) Place the test specimen in an oven or liquid bath, holding the specimen’s temperature to within ± 1o C throughout the test.

b) Elevate the pressure on the PRD inlet to 130% of the working pressure and hold this constant to within ± 0.7 MPa (7 bar) until activation. Limit the volume of liquid or gas to prevent damage to the test apparatus upon activation and venting. Each device may be pressurized individually or through a manifold system. If a manifold system is used, each pressure connection shall include a check valve to prevent pressure depletion of the system.

11.1.2.3 Long-Term Temperature

5 (Five) samples shall be tested. The test can be carried out only on PRD also.

It is assumed that the time-to-activation, t, of fusible alloys is a rate process governed by the power-law relationship of the formula. t = A.TB Where, T is temperature, and A, B are constants dependent upon the fusible alloy and PRD design. The calculated time-to-activation for the PRD shall be greater than one year at 82o C and at least 20 years at 57o C, and shall exceed 500 h, long-term test temperature.

Mathematical manipulation results in the following requirement for long-term test temperature.

TL = T (0.057) 0.34{log (T/Tf)}

Where TL = long-term test temperature in o C; Tf = fusible material yield temperature, in o C; T = 82 o C; and log = 10


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Based on the actual yield temperature of the fusible alloy, long term temperature shall be calculated. The test specimen shall be placed in an oven or liquid bath, holding the specimens temperature to long term temperature ± 1 o C. The pressure on PRD inlet shall be elevated to 130 % of working pressure and be held constant within ± 0.7 MPa until activation. The test shall be carried out in case of Combination Relief Devise on 5 (five) PRDs and in case of only thermally activated type on 3 (three) PRDs and comply with the following requirements:

a) In case of only thermally activated Relief Devices:

The time to activation for long term test devices shall exceed 500 h.

b) In case of Combination Relief Devices: i. 2 (Two) PRDs shall be tested at the fusible material yield temperature to verify that

they activate in less than 10 h; and ii. 3 (Three) PRDs shall be tested at their long term test temperature. The time to

activation for long term test devices shall exceed 500 h.

11.1.3 Continued operation (Cycle) Test 5 (Five) valves selected at random and the pressure relief device of the valve shall be tested for continued operation with water or air at between 10 % and 130 % of the working pressure at a maximum cyclic rate of 10 cycles per minute at a temperature given in the Table below:

Table: Test Temperatures & Cycles Temperature ±2 deg C

Cycles No. of Test Valves

82 2000 2 57 18000 2

The test can be carried out with or without the CNG Valve. Following the cyclic test there shall be no extrusion of the fusible material from the pressure relief device and no failure of Bursting Disc, if any. After completion of the test, PRD shall meet all the requirements of Leakage Test (11.1.7) and Activation Test (11.1.8). 11.1.4 Thermal Cyclic Test One CNG valve shall be thermally cycled between –20o C and 82o C as given below:

a) A depressurized PRD shall be placed in a fluid bath maintained at –20o C or lower for a period of 2 h or more. Then the device shall be transferred to a fluid bath maintained at 82o C or higher within 5 min.

b) The depressurized PRD shall be kept in the fluid bath maintained at 82o C or higher for a period of 2 h or more. Then the device shall be transferred to the fluid bath maintained at –20o C or lower within 5 min.


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The above steps shall be repeated to achieve a total of 15 thermal cycles. Then the PRD shall be cycled between 10 % and 100 % of the designed working pressure for a total of 100 cycles. After completion of the test, PRD shall meet all the requirements of Leakage Test (11.1.7) and Activation Test (11.1.8). 11.1.5 Condensate Corrosion Resistance Test

Select 1 (one) valve at random and seal the outlet part of the PRD. Fill the PRD with test solution given in 11.1.5.1 and soak the device for 100 h at room temperature. Empty the solution from the PRD and reseal the outlet port, then heat the device for an additional 100 h at 82o C.

After completion of the test, PRD shall meet all the requirements of Leakage Test (11.1.7) and Activation Test (11.1.8).

11.1.5.1Test Solution Composition:

The test solution, by volume percentage, consists of: a) 84.8 % Stoddard solvent, b) 10.0 % Benzene, c) 2.5 % fryquel No.15 or No.20 compressor oil, d) 1.5 % water, e) 1.0 % methanol, and f) 0.2 % Ethyl mercaptan (also known as Ethanethiol)

11.1.6 Vibration Test

1 (One) CNG valve shall be vibrated for 2 h in a test apparatus at 17 Hz with amplitude of 1.5 mm in each of the three directions (90o towards each other).

On completion of this total 6 h of vibration, the valve shall comply with the requirements of Leakage Test (11.1.7) and Activation Test (11.1.8).

11.1.7 Leakage Test at Low and High Temperature:

The pressure relief device of the valve shall be tested for leakage test at following temperature and pressure irrespective of the design working pressure of the valves.

Temperature deg C

Pressure MPa

-20 15 82 26

The PRD shall be either bubble free or have a leakage rate less than 10 bubbles per minute from a tube of 2.5 mm inside diameter against a water seal of maximum 25 mm.

11.1.8 Activation Test

11.1.8.1General The purpose of this test is to demonstrate that PRD’s will activate and function properly.

Test 1 (one) PRD without subjecting to other tests in order to establish a base line time for activating.

In case of only Fusible Plug as PRD, test for thermally activated PRD as per 11.1.8.2 and in case the


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relief device is activated by a combination of high pressure and temperature acting together shall be tested in accordance with 11.1.8.3 and PRD only with bursting disc shall be tested in accordance with 11.1.8.4.

PRD subjected to ‘Continued operation – Cycle test’ (11.1.3), Thermal Cyclic test (11.1.4), Condensate Corrosion Resistance Test (11.1.5) and Vibration tests (11.1.6) shall activate within the time limit defined under requirement in 11.1.8.2, 11.1.8.3 and 11.1.8.4 as applicable.

11.1.8.2 Thermally Activated Relief Device (PRD having fusible plug only)

a. Test Setup: The Test Set Up shall consist of an oven capable of maintaining temperature at 600 o C ±10 o C inside the oven. The PRD shall not be exposed directly to the flame.

b. Test Procedure: i. Pressurise the PRD to 25% of working pressure

ii. Insert the PRD in the oven area having temperature at 600 o C ±10 o C. iii. Record time of activation (t)

c. Requirement: The PRD subjected to Cycle test (11.1.3), Thermal Cyclic test (11.1.4),

Condensate Corrosion Resistance Test (11.1.5) and Vibration tests (11.1.6) shall activate to meet the requirement of ≤ t + 4 minutes, where ‘t’ in minutes is the time to activate the PRD not subjected to these tests.

11.1.8.3 Combination Relief Device

a) Test Setup: Place the PRD in oven to a temperature of 10 o C above the yield temperature of the fusible alloy.

b) Test Procedure: i. Activate the PRD by pressurizing until the rupture disc bursts.

ii. Record the pressure of activation

c) Requirement: The PRD subjected to Cycle test (11.1.3), Thermal Cyclic test (11.1.4), Condensate Corrosion Resistance Test (11.1.5) and Vibration tests (11.1.6) shall activate at a pressure > 75% and < 105% of the activation pressure of a PRD not subjected to any previous testing.

11.1.8.4 Pressure Activated Relief Device (PRD having bursting disc only)

a) Test Setup: Test the bursting pressure of the bursting disc at room temperature.

b) Test Procedure: i. Activate the PRD by pressurizing until the rupture disc bursts.

ii. Record the pressure of activation

c) Requirement: The PRD subjected to Cycle test (11.1.3), Thermal Cyclic test (11.1.4), Condensate Corrosion Resistance Test (11.1.5) and Vibration tests (11.1.6) shall activate at a pressure > 75% and < 105% of the activation pressure of a PRD not subjected to any previous testing.


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12 PRODUCTION INSPECTION AND TESTING 12.1 Tensile and Elongation test:

Samples from each batch of valve bodies as per Table A of 12.1.9 (Scale of Sampling) shall be subjected to the test for tensile and elongation of the material of the valve body for meeting the requirements as per 5.3.1 and the lot shall be declared satisfactory with respect to the requirement of tensile and elongation test if each sample passes the test satisfactorily.

12.2 Izod Impact test

Samples from each batch of valve bodies as per Table A of 12.1.9 (Scale of Sampling) shall be subjected to the impact test (Izod impact strength) for meeting the requirements as per 5.3.2 and the lot/batch shall be declared satisfactory with respect to the requirement of Izod impact test if each sample passes the test satisfactorily.

12.1.3 Internal and External Tightness Test at Working Pressure: Every valve shall be tested for external and internal leakage by air or Nitrogen at room temperature only at working pressure (Pw). The internal and external leakage shall not exceed 6 cm3/h.

For valves equipped with pressure relief device, testing shall be done at 0.8 times the maximum rated burst pressure of pressure relief device.

Closing torque will not exceed Te start during internal leakage testing.

12.1.4 Internal & External Tightness Test as per Table-14:

Samples from each batch of valve bodies as per Table A of 12.1.9 (Scale of Sampling) shall be tested for internal & external tightness by air or Nitrogen at pressures given in Table-14 at room temperature. Closing torque will not exceed Te start during internal leakage testing. Valve equipped with pressure relief device, if required, may be rendered inoperative for this test. Following the test, the pressure relief device shall be restarted and restored. 12.1.5 Checking of Pressure Relief device (PRD):

12.1.5.1 Valves equipped with bursting Disc only- checked for bursting pressure of the disc as per procedure described in IS: 5903 and scale of sampling will be as per Table C of 12.1.9.

12.1.5.2 Valves equipped with fusible Plug only- will be checked for yield temperature of the fusible metal will be checked as per procedure described in IS: 5903 and scale of sampling will be as per Table C of 12.1.9.

12.1.5.3 Valves having Combination Relief Device - fusible plug and burst disc to be tested separately to the requirements of 12.1.5.1 and 12.1.5.2 respectively.

12.1.6 Checking of Valve inlet : Samples from each batch of valves as per the Scale of Sampling given in Table B of 12.1.9 will be checked for inlet dimension. The threads shall be checked by calibrated gauges.


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12.1.7 Checking of Valve Outlet : Samples from each batch of valves as per the Scale of Sampling given in Table B of 12.1.9 will be drawn to check outlet dimensions. The threads shall be checked by calibrated gauges.

For Pin Index valves, valve body dimensions as per Fig. 14 to 24, as applicable, will be checked. Outlet hole position shall be checked by calibrated Receiver gauge.

12.1.8 Checking for other dimensions :

a) For Key operated valves, the square of the spindle and for Pin-index Valves the width of the spindle will be checked as per requirement of Table 1.

b) For Pin-index valves, other dimensions as per Fig. 8a or 8b, as applicable, will be checked.

Scale of Sampling will be as per Table A of 12.1.9

12.1.9 Scale of Sampling:

12.1.9.1 In any consignment all valve body blanks of same material and size manufactured under similar processes of production shall constitute a lot/batch. 12.1.9.2 The number of valve bodies/valves to be selected from a lot/batch shall depend upon the size of the lot/batch and shall be in accordance with respective tables for identified inspection/tests as under. 12.1.9.3 The lot/batch shall be declared satisfactory with respect to the requirement of the given test if each sample as per the scale of sampling passes the test satisfactorily. If any test sample, tested to Tensile & Elongation (5.3.1) and Izod Impact Test (5.3.2), fails to meet the specified requirements therein, additional specimens equaling twice the number of sample size for the failed test in the same lot/batch shall be taken and tested for the failed test only. If any of these specimens fails to meet the requirement, the entire lot/batch represented shall be rejected.

Table A – Scale of sampling Mechanical properties (12.1.1 and 12.1.2), Other dimensions (12.1.8) and tightness test (12.1.4)

Lot / Batch size Sample size Up to 500 2 501 up to 1000 4 1001 up to 2000 6 2001 to 3000 8

Table B – Scale of sampling

Inlet & outlet dimensional check (12.1.6, 12.1.7)

Lot / Batch size Sample size Up to 500 10 501 up to 1000 15 1001 up to 2000 20 2001 to 3000 25


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Table C – Scale of sampling

PRD (Bursting disc & yield temperature)

Lot / Batch size Sample size From 3 to 8 2 From 9 to 15 3 From 16 to 30 4 From 31 to 100 6 From 101 to 250 8 From 251 to 1000 10 From 1001 to 3000 15

13 MARKING The valve shall be permanently and legibly marked with the following information:

a) Year and month of manufacture (YYYY/MM) b) Manufacturer’s identification symbol c) Number of this standard d) Working pressure of the valve e) Identification of the valve inlet connection f) Identification of the valve outlet connection g) The specified bursting pressure of the bursting disc (if provided) h) Yield temperature of the fusible plug (if provided)


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Annex A (Clause 2)

IS No. Title

319:2007 Free cutting leaded bass bars, rods and section - Specification (fifth revision) 1068:1993 Electroplated coatings of nickel plus chromium and copper plus nickel plus

chromium (third revision) 1598:1977 Method for bend test (second revision) 1608:2005 Mechanical testing of metals - Tensile testing (third revision) 2643:2005 Pipe threads where pressure-tight joint are not made on the threads -

Dimensions, tolerances and designation (third revision) 3745:2006 Yoke type valve connection for small medical gas cylinders - Specification

(second revision) 6912:1985 Copper and copper alloy forging stock and forgings (first revision) 7202:1974 Specification for inspection gauges for checking threads of gas cylinder valves

for use with breathing apparatus 7302:1974 Specification for valve fittings for gas cylinder valves for use with breathing

apparatus 8737:1995 Valve fittings for use with liquefied petroleum gas (LPG) cylinders of more than

5 litre water capacity - Specification (first revision) 8775:1978 Filling pressure and corresponding developed pressure for permanent gases

contained in gas cylinders 8866:1978 Filling ratios and corresponding developed pressure for high pressure liquefiable

gases contained in gas cylinder 8867:1978 Saturated vapour pressure and test pressure for low pressure liquefiable gases

contained in gas cylinders 9122:2008 Inspection gauges for checking type 2 Taper threads of gas cylinder valves,

Taper 3 in 25 - Specification (first revision) 12300:1988 Valve fittings for refrigerant cylinders - Specification 15984:2011 Inspection gauges for checking type 1 (sizes 1, 2 and 3) taper threads of gas

cylinder valves and cylinder necks - Taper 1 in 16 on diameter - Specification

Documents

Dear Sirs, Please find enclosed the following documentsbis.org.in/sf/med/MED16-1212.pdf · Please find enclosed the following documents: Doc. No ... 0.3This Indian Standard also covers