draft for comments only draft indian standard low …0980-0981).pdf · 1 draft for comments only...

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Draft for Comments Only

Draft Indian Standard LOW PRESSURE REGULATORS FOR USE WITH LIQUEFIED PETROLEUM

GAS (LPG) – SPECIFICATION (Second Revision of IS 9798)

ICS 23.060.40; 75.160.30

_________________________________________________________________________ Not to be reproduced without the permission of Last date for receipt of BIS or used as a STANDARD comments is: 31 October 2008 _________________________________________________________________________ FOREWORD Adoption clause will be added later on. This Indian standard was first published in 1981 and revised in 1995. Since then many suggestions were received for its improvement and with the result Amendments No.1 to 3 were issued. This standard is revised to incorporate the amendments issued and the suggestions received from time to time. In this revision following modification has been incorporated:

i) Figures for outlet threaded connection incorporated; ii) Material clause has been modified, and iii) Number of cycles in cycle test modified iv) Requirements for excess flow valve incorporated; v) Strength test incorporated;

In the preparation of this standard considerable assistance has been derived from EN 12864:2001 “Low pressure non adjustable regulators having a maximum pressure of less than or equal to 200 m bar with a capacity of less than or equal to 4 kg/h and their associated safety devices for butane, propane or their mixtures” The quantities in this standard have been expressed in technical metric units. However, in view of the introduction of International System (SI) units in the country, the relevant SI units and corresponding conversion factors are given below for guidance: 1 kgf/cm2 = 98.066 5 kPa (kilopascal) = 10 m of Water column (WC)

= 0.980 665 MPa (megapascal) = 0.980 665 bar

1 Pa = 1 N/m2 Pressures indicated in the various requirements/clauses of this standard are gauge pressure unless otherwise stated. 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 IS 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.

Doc: ME 16(0980)c August 2008

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1 SCOPE This standard specifies materials, construction, performance and testing requirements for low pressure single or two stage regulators and automatic change-over devices for use with liquefied petroleum gas mixtures in vapour phase up to 4.903kN/m2 [50gf/ cm2 or 500mm water column (WC)] outlet pressure.

Note - Low pressure is considered to be any pressure below 6.894kN/m2 (70.3gf/cm2). Domestic and commercial appliances normally operate at gas pressure of 2.942 kN/m2 (30 gf/cm2 or 300mm water column).

2 REFERENCES The standards given in Annex A contain provisions, which through reference in this text, constitute provisions of this standard. At the time of publication, the editions indicted were valid. All standards are subject to revision and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated at Annex A. 3 TERMINOLOGY 3.1 Commercial Butane A hydrocarbon product composed predominantly of butanes (n and iso), butylenes or their mixtures of maximum vapour pressures 980 kPa (10 kgf/cm2 ). 3.2 Commercial Butane/Propane Mixture A hydrocarbon product composed predominantly of a mixture of butanes (n and iso) and/or butylenes with propane, and/or propylene of Max vapour pressure of 1653 kPa (16.87 kgf/cm2). 3.3 Commercial Propane A hydrocarbon product composed predominantly of a mixture of propane, propylene or their mixtures of maximum vapour pressure of 2548 kPa. (26 kgf/cm2). 3.4 Lock-up Pressure The outlet pressure of the regulator under ‘no-flow’ conditions, which shall be achieved within 60 s after cessation of flow, with the inlet pressure to the regulator remaining on. 3.5 Nominal outlet pressure The basic rated outlet pressure desirable in a regulator set at 50 percent rated capacity at a specific inlet pressure. The nominal outlet pressure rating for domestic regulator is 2.942 kN/m2 (30gf/cm2 or 300 mm water column). 3.6 Rated capacity The standard rated capacity for LPG regulators for domestic use is up to 500l/h of LPG vapour. For purpose other than domestic, higher capacity regulators could be used. For

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purposes of performance tests, the flows are rated in terms of percentages of rated capacity, so as to cover all low pressure whatever the rated capacity. 3.7 Single Stage Regulator Regulator in which the reduction of inlet pressure down to the desired regulated outlet pressure is achieved in one stage only. 3.8 Two Stage Regulators In this configuration, the inlet pressure is reduced to the desired outlet pressure is two stages by an arrangement in the same regulator only. The first stage regulation governs the reduction of the inlet pressure to an intermediate pressure and the second stage regulation governs the reduction of this intermediate pressure to the desired outlet pressure. Both stages may be incorporated in one body. 3.9 Automatic Changeover Device A device to ensure continuity of gas supply where a reserve gas supply is brought into use automatically when the ‘service’ gas supply is exhausted. This may or may not incorporate a second stage regulation. Note – A typical automatic changer over device is illustrated in Fig. 1A. 3.9.1 Indicators An indicator shall be fitted to show when the supply cylinder(s) or vessel(s) is empty and the reserve supply is being used. 3.9.2 Non return valve shall be fitted to the inlet of automatic changeover device to prevent possible discharge of gas when changing cylinders. The arrangement shall be such that it cannot readily be disconnected from the device when changing cylinders. When pressure tested against the direction of flow, maximum leakage rates shall not exceed 4N mm3/s at standard temperature and pressure. The test shall be carried out at the following pressures:

a) at 0.350 kgf/cm2 minimum pressure; and b) at 20 kgf/cm2 maximum pressure.

4 MATERIAL 4.1 All component parts shall be manufactured from or be treated with materials compatible with LPG as well as be unaffected by chemical or thermal influences that may be encountered in normal use. 4.1.1 Brass parts shall not be susceptible to season cracking. The susceptibility to season cracking shall be determined by the method in IS 2305. 4.2 The body for all regulators of rated capacity 1000 l/h shall be manufactured from alloys of zinc by pressure die-casting. Chemical composition of material shall conform to IS 742.


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4.2.1 Finish The body and the cover of the regulator shall be electroplated or chemically treated (surface passivated) and painted or powder coated so as to resist the effect of atmospheric conditions to which the pressure regulator is exposed during its working life. The type of finish shall be as agreed between the manufacturer and the customer. The surface finished components shall be subjected to test for corrosion resistance as per IS 9844. The criteria of acceptance after the test shall be the rating number as given in 6 of IS 6009. The painted or powder coated surfaces shall be tested for adhesion of paint by the method described in Annex H. 4.3 Diaphragm Material The material of diaphragm shall be of synthetic rubber or other material equally suitable for the application and shall satisfy the following requirements. 4.3.1 The material shall be free from porosity, pits and foreign particles and shall have a smooth, non-tacky surface with minimum talc or bloom. 4.3.2 The material shall not show changes of more than 10 IRHD when subjected to ageing of 72 h at 70oC in accordance with the method prescribed in 3 or 4 of IS 3400 (Part 4).

Note – For guidance purpose, comparison of Shore A and IRHD hardness are given below:

Shore A 30 40 50 60 70 80 90 100 IRHD 28.9 39.5 50 60.5 70 80 89.5 100 4.3.3 The material shall be compatible of withstanding a clamping pressure of 490 kPa (5 kgf/cm2) whereby the material itself or the substance with which the fabric layer has been impregnated shall not be pressed away, flowed away or be bruised of otherwise damaged. 4.3.4 The material shall be such that when an assembled regulator is subjected to the test as specified in Annex C, the diaphragm shall not pull out or burst at a pressure less than 275 kPa (2.8 kgf/cm2) 4.3.5 The material shall, after immersion In pentane of commercial LPG for 72 h, meet the appropriate requirements specified in Annex D. Changes in hardness, before and after the immersion shall not exceed 15 IRHD [see IS 3400 (Part 2)].

Note – The tests at 4.3.1 to 4.3.5 are work batch tests. On initial selection of a diaphragm material, it shall also be tested in commercial LPG in vapour phase for 72 h and shall not show a weight loss or volume change greater than 15 percent.

4.3.6 The material shall be such that the flexibility of the diaphragm shall not be impaired after the samples of the same have recovered completely to ambient temperatures from cooling to -20oC or heating to 65oC. For these tests, assembled regulators are cooled to -20oC or heated to 65oC and maintained at these temperatures for 10 min and then kept in atmosphere to recover completely to ambient temperature of its own (not by induced heating or cooling). After recovery, the setting and performance readings are taken. The readings shall be within the acceptable limits of performance as given in 8.9.

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4.4 Valve Pad Material Valve pad material shall be of synthetic rubber or other material equally suitable for the application and of a quality to satisfy the following minimum requirements. 4.4.1 The valve pad material shall be free from porosity, pits and foreign particles and shall have a smooth non-tacky surface with minimum talc or bloom. The material shall have low compression set, cold flow and creep characteristics. 4.4.2 The material shall, after immersion in pentane or commercial LPG for 72 h, meet the appropriate requirements tabulated in Annex D. After this test, change in hardness value from before and after the test shall not exceed 15 IRHD.

Note – The tests at 4.4.1 to 4.4.2 are work batch tests. On initial selection of a valve pad material, it shall also be tested in commercial LPG in vapour phase and shall not show any volumetric shrinkage or increase greater than 10 percent. The loss of plasticizers or other ingredients due to extraction shall not exceed 5 percent by weight.

4.4.3 The material shall not show change of more than 10 IRHD when subjected to ageing of 72 h at 70oC in accordance with the method prescribed under 3 or 4 of IS 3400 (Part 4). 4.4.4 The valve pad fitted in its housing shall be immersed in pentane or commercial LPG (see Annex E) in vapour phase for 72 h after which the valve pad shall not show evidence of being forced out of position due to swelling or other cause. 4.5 Seals O rings and rubber components other than diaphragm and valve pad shall withstand the requirement as laid down in 4.4.1 to 4.4.3.

NOTE – Rubber materials which come in contact with LPG shall be tested. 5 CONSTRUCTION AND WORKMANSHIP 5.1 A typical regulator to match self closing valve is shown in Fig. 1 for illustration purpose. 5.2 The regulator, including all the component parts, shall be mechanically strong, of sound construction and of high standard of workmanship and finish. 5.3 The components of a regulator shall be interchangeable with the corresponding components of any other regulator of the same model and size. 5.4 Screw Thread Except for the screw ends of regulators not fitted with inlet of outlet connectors, screw threads shall comply with the requirements of IS 554 or IS 2643 or IS 4218 (Part 1 to 4) or IS 14962 (Part 1 to 5).


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5.5 Inlet Connection Where screwed connections are not used, the inlet of the pressure regulator shall be cast integrally as an inseparable part of the body or so fixed which cannot be separated without damaging the body. The size and the profile of the inlet connection shall match the outlet end of the spring actuated self closing valve of LPG cylinder to achieve a leak proof coupled joint without use of a resilient packing or washer or gasket as a part of the regulator. However, the use of a gasket or packing shall be permitted so long as there is a leak proof joint with the valve, with the help of the gasket of packing as a part of the regulator. 5.5.1 The inlet connection shall be designed to withstand a minimum hydrostatic pressure of 1.5 times the saturated vapour pressure of the gas at 65oC subject to a minimum of 18 kgf/cm2 for 120 s. 5.5.2 The inlet connection shall also be capable to withstand a minimum pneumatic pressure of 1666 kPa (17 kgf/cm2) at ambient temperature. 5.5.3 Where screwed connections are used for inlet or outlet of regulator or cylinder changeover devices, the following shall apply:

a) Screwed Ends – Where inlet or outlet connections are not fitted, the inlet and outlet of a regulator with screwed ends shall comply with the requirements of IS 2643 or IS 4218 (Part 3).

b) Inlet Connections – Where used, any washer, connector and nut of a screwed inlet union shall comply with the applicable mating dimensions of IS 8737 or suitable for gas reticulated systems.

5.6 Outlet Connection 5.6.1 Non-threaded Outlet Connection For regulators for domestic service the outlet nozzle shall be horizontal cast integrally with the body. The nozzle shall be any of the two specified in Fig. 2A and 2B. The choice of type shall be as per the agreement between the manufacturer and the purchaser. 5.6.2 Threaded Outlet Connection Threaded outlet connection shall be any of the two as per Fig. 3A and 3B for regulations with threaded outlet. The choice of type shall be as per the agreement between the manufacturer and the purchaser. 5.6.3 Any other type of outlet connections may be permissible as per agreement between the manufacturer and the purchaser subject to approval from statutory authority. 5.7 Body 5.7.1 The body and cover shall be strong enough to withstand the stress of connecting the regulator to the cylinder valve or piping installation and to withstand normal stress imposed by service conditions, without developing leakage at joints, permanent deformation or other damage which might impair the serviceability of the regulator.

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5.7.2 After machining and before finishing treatment (for example painting) the body shall be pressure tested for porosity with gas or air at a pressure of not less than 98 kPa (1.0 kgf/cm2)

5.8 Vent The breather hole (air vent above diaphragm space) shall be of such size and at such location on the cover that:

a) Does not easily get clogged/blocked, b) The accidental entry of foreign matter is minimized, and c) It would be difficult for an instrument inserted through the air vent hole to

reach the diaphragm.

5.9 Pressure Relief Valve Where a pressure relief valve is incorporated in the design, it shall be set to discharge at a pressure not less than twice and not more than three times the outlet pressure setting of the regulator.

NOTE – Provision of a threaded insert screened hole may be as per agreement between purchaser and manufacturer, so that any discharge from the relief valve may be safely led away. This is applicable to low pressure regulators used for purposes other than domestic.

5.9.1 Excess Flow Valve The excess flow valve if provided shall meet the requirements given in Annex B. 5.10 Valve Pad Fitting 5.10.1 A valve pad (resilient) shall be so retained without the use of adhesive that it cannot loosen or work out of position under service conditions.

5.10.2 The inlet orifice and the valve pad of the pressure regulator shall be protected by provision of a filter of suitable material compatible with LPG, of appropriate size of perforations that does not hamper flow of vapour but is yet effective against ingress of contaminating agents in the gas. Any acceptable arrangement meeting this requirement, as agreed to between the manufacturer and the purchaser is permitted. 5.11 Strength of Connections 5.11.1 Strength of the Connection/Regulator Assembly Whether the fixing of the inlet connection onto the regulator body is of the threaded or non threaded type or in one piece, there shall no damage or distortion that could affect the safety of the regulator at the end of the tests in 8.11 carried out with the following values: a) A torque of at least 30 N.m in both directions (see Table 3);

b) A bending moment created by a force of 400 N directed upwards and whose application point is at the base of the outlet connection (see Table 5); and

c) A tensile strength test of 2 000 N (see Table 3).


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Whether the fixing of the outlet connection onto the regulator body is of the threaded or non threaded type or in one piece, there shall no damage or distortion that could affect the safety of the regulator at the end of the tests in 8.11 carried out with the following values: a) Non-threaded hose connections

1) a torque of at least 30 N.m in one direction (verification not required for one piece connection and for freely rotating connections);

2) a bending moment of 10 N.m; 3) a tensile strength test of 2 000 N (verification not required for one

piece connection). b) Threaded connections

4) a torque of at least 30 N.m in both directions (verification not required for freely rotating connections);

5) a bending moment of 10 N (not required for one piece connection); 6) a tensile strength test of 2 000 N (not required for one piece

connection). In addition, for freely rotating connections, the torque necessary for the rotation of the connection shall not be greater than 0.5 N.m at the end of all the tests carried out. 5.11.2 Strength of Regulator Assembly When Fitted Onto its Cylinder Valve Following the tests in 8.11, Table 5 carried out with the regulator fitted to the installation as indicated in the instructions with the following values, there shall be no damage or distortion that could affect the safety of the regulator:

a) a torque in both directions

1) of at least 20 N.m for non-threaded hose outlet connections (15 N.m for quick coupling connections);

2) of at least 30 N.m for threaded outlet connections. In addition, regulators with screwed unions vertically mounted onto the cylinder valve shall be subjected to a torque of at least 20 N.m in the regulator plane (15 N.m for quick coupling connections).

b) a bending moment created by a force of 400 N directed upwards and whose

application point is at the base of the outlet connection

c) a tensile strength test of 500 N (verification not required for inlet connections screwed onto the cylinder valve).

The mechanical strength required shall be ensured whatever the position of fixing of the regulator onto the installation.

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6 SOUNDNESS

6.1 A regulator shall be considered leak tight when tested in accordance with 6.2 and if the leakage rate does not exceed 4 N mm3/s (the symbol N indicates conversion to normal temperature and pressure conditions, NTP that is 760 mm of Hg and 0oC) .

6.2 The regulator shall be leak tight when tested pneumatically at a pressure of 0.490 kN/m2 (5 gf/cm2) below twice the nominal outlet pressure when fitted with a relief valve or 14.70 kN/m2 (150 gf/cm2) when not fitted with a relief valve, applied through the outlet connection of a fully assembled regulator and held for not less than 30 s and not more than 60 s after stability has been achieved. To get stability, adequate time is allowed between introduction of test medium and the start of observation, so that the internal parts have attained balanced positions.

6.3 Those parts of the regulator which are normally subjected to the full cylinder pressure shall be leak tight at a minimum hydrostatic pressure of 1.5 times the saturated vapour pressure of the gas at 65˚C subject to minimum of 18 kgf/cm2 for a period of 120 seconds. To ensure that the hydrostatic pressure and medium extends only in and up to the high pressure sections, a pneumatic back pressure not exceeding 14.70 kN/m2 (150gf/cm2) is applied to the outlet connection of the regulator before the start of the test and is kept on throughout the test. Any change in the back pressure shall be ignored for judging the result of the test. 6.4 Those parts of the regulator which are normally subjected to the full cylinder pressure shall also be tested for soundness at a pressure of 1666 kPa (17kgf/cm2) for a period of not less than 30 s and not more than 60 s, after stability has been achieved. To ensure that the hydrostatic pressure and medium extends only in and up to the high pressure sections, a pneumatic back pressure not exceeding 14.70 kN/m2 (150 gf/cm2) is applied to the outlet connection of the regulator before the start of the test and is kept on throughout the test. Any change in the back pressure shall be ignored for judging the result of the test. 7 RANGE OF PRESSURE ADJUSTMENT 7.1 The standard range of pressure adjustment, the range of inlet pressure and the range of outlet pressures is elaborated in 7.2 and 8.9.1. This does not preclude any specific requirement deviating from the standard, as may be agreed to between the manufacturer and the purchaser, provided the essentials of the standard ranges are maintained. 7.2 For the purpose of performance test of domestic service regulators, the standard range of inlet pressures for use with commercial butane, commercial butane/propane mixture and commercial propane shall be as per Table 1.


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Table 1 Performance Test

(Clauses 7.2 and 8.9.1)

Regulator for gas

Inlet pressure kgf/cm2

Flow in % of rated capacity

Range of outlet pressure mm of

W.C.

Commercial Butane

0.5 – 17 17.0

100 – 10 0

225 – 400 450 Max

Commercial butane/ propane mixture

0.5 – 17 17.0

100 – 10 0

225 – 400 450 Max

Commercial propane

0.5 – 20 20.0

100 – 10 0

225 – 450 500 Max

Note - LPG Regulator may be used for ‘Butane gas’ applications. 8 SETTING AND PERFORMANCE 8.1 Test Gases The performance tests shall be carried out using air, after making due provision for a factor of conversion representing the flow of appropriate gas for which the regulator is designed, that is, butane, propane, or mixture for the equivalent vapour condition The volume conversion factors for certain gases are given in Table 2:

Table 2 Volume Conversion Factors (Clause 8.1)

Multiply flow of By To obtain flow of Air 0.707 Butane 1.290 Natural gas 0.808 Propane 0.75 120 RVP Butane/ Propane mixture 120 RVP Butane/ Propane 1.333 Air mixture Butane 1.414 Air 1.826 Natural gas 1.140 Propane Natural gas 0.775 Air 0.547 Butane 0.625 Propane Propane 1.237 Air 0.874 Butane 1.598 Natural gas The above data serves as a guide also in cases where the percentage composition of constituents in an LPG mixture are known.

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8.2 Chatter A regulator using the gas for which it is designed shall not chatter or vibrate while being tested for performance

Note – It is improper to induce chatter by striking the regulator severely or by using an output in excess of the maximum rated capacity, conditions which may induce vibrations of the internal components and give a false impression of chatter.

8.3 Orientation A regulator when installed shall be capable of operating in al orientations. The standard performance tests shall be carried out with the regulator in its recommended orientation. 8.4 Outlet Pressure Measurement For measurement of outlet or delivery pressures of the regulator, a water-in-glass-tube-manometer shall be used. The pipe between the outlet of the regulator and the outlet pressure gauge or manometer shall be of the bore not less than the outlet of the regulator and of length not so long as to create a significant pressure drop. 8.5 Flow measurement shall be carried out using a direct indicating flow meter (rota -meter). Calibrated orifices may also be used. 8.6 Inlet Pressure Deviation During the tests for performance it may be noted that there is a slight deviation of the inlet pressure, especially at lower ranges, at varying outlet flows of the regulator under test. The inlet pressure should be readjusted appropriately when such deviation is experienced. 8.7 Lock up shall be achieved within 60 s after cessation of flow. 8.8 Unless otherwise specified, performance tests shall be carried out at ambient temperatures. 8.9 Performance 8.9.1 The regulators shall be set as given in Table 1. 8.9.2 A regulator shall not chatter or vibrate while being tested at any flow or inlet pressure in the range prescribed for the performance tests or under condition simulating normal service. If chattering or vibration occurs when using air or nitrogen or permitted medium, the test shall be repeated using the gas for which the regulator is designed. 8.10 The requirements of performance as given in 8.9 shall also be satisfied before and after subjecting the regulator to tests specified in 8.10.1, 8.10.2 and 8.10.3. Deviation in the initial setting, after these tests, is acceptable.


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8.10.1 Cycle Test When assessing a new design, a type approval test in accordance with Annex F shall be carried out. A fully assembled regulator shall withstand a minimum of 50 000 cycles of opening and closing operations, after which it shall be subjected to a soundness test as in 6.2, 6.3, 6.4 and performance as in 8.9. 8.10.2 Low Temperature Test The regulator is exposed to a temperature of -20oC for a minimum period of 10 minutes for the complete assembled unit to attain this temperature. It is then removed and left exposed to ambient conditions, after which it is tested. The method of carrying out the test is elaborated in Annex F. 8.10.2.1 Heating shall not be applied to reach the ambient temperature. 8.10.2.2 Care shall be taken to avoid intrusion of fluid or moisture into the regulator assembly during cooling and recovery. For this the outlet nozzle, the inlet and the breather hole may be plugged. 8.10.3 High Temperature Test The regulator is exposed to a temperature of 65oC for a minimum period of 10 minutes for the complete assembled unit to attain this temperature. It is then removed and left exposed to ambient conditions, after which it is tested. The method of carrying out the test is elaborated in Annex F. 8.10.3.1 Forced cooling shall not be applied to reach the ambient temperature. 8.10.3.2 Care shall be taken to avoid intrusion of fluid or moisture into the regulator assembly during heating and cooling. For this the outlet nozzle, the inlet and the breather hole may be plugged. 8.11 Mechanical Strength of Connections Tests for mechanical strength shall be carried out using a dynamometric device with an accuracy of ± 5 percent. For the torque test, a system which neutralizes bending moments shall be used (if a torque wrench is used, it is desirable that this is double handed). The regulator is fixed at the points indicated in the drawings in Tables 3, 4 and 5. The duration of application of the torques and forces shall be 1 min. For the test carried out in accordance with Table 5.

i) Regulators with threaded connections, the connection shall be mounted on its valve as indicated in the table 5;

ii) Regulators with quick couplings, if the inlet connection rotates, the tensile strength test of 15 N.m is not necessary; if the connection is locked in the original position, the regulator shall be tested as such.

In all cases the requirements of 5.11 shall be met.

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9 SEALING 9.1 If the regulator is permanently not crimped, the body and the cover of each regulator shall be sealed to discourage interference with the internal mechanism as well as the pressure setting. 9.1.1 The manner of sealing shall be as agreed to between the purchase and the manufacturer. 10 CLASSIFICATION OF TESTS 10.1 Type tests The following shall constitute type tests out of the various requirements:

a) Diaphragm material (4.3); b) Valve pad material (4.4); c) Hydrostatic test (6.3); d) Body (5.7.2);

e) Low and high temperature tests (8.10.2 and 8.10.3); and f) Mechanical strength of connection (8.11).

10.2 Routine tests The following shall be carried out as routine tests: a) Pneumatic test (6.2 and 6.4); and b) Chatter and performance test (8.9) 11 MARKING 11.1 A Regulator shall be clearly and permanently marked with the following: a) Manufacturer’s name or trade mark; b) Month and year of manufacture, for example 12-08 for December 2008; c) Rated capacity in m3/h of gas designed for; d) Number of this standard;

e) Any other markings agreed to between the purchaser and the manufacturer; and f) Name of the gas designed for.

11.2 BIS Certification Marking The regulators may also be marked with Standard Mark. 11.2.1 The use of Standard Mark is governed by the provisions of Bureau of Indian Standards Act, 1986 and the rules and Regulations made thereunder. The details of conditions under which the license for use of Standard Mark may be granted to manufacturers or producers may be obtained from the Bureau of Indian Standards. 11.3 The markings may be distributed over the body, cover and sealing plate/cap as found convenient and as agreed to between the purchaser and the manufacturer.


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ANNEX A (Clause 2)

LIST OF REFERRED INDIAN STANDARDS

IS No. Title

554: 1999 Pipe threads where pressure tight joints are made on the threads – dimensions, tolerances and designation (fourth revision)

IS 742 : 1981 Zinc base alloy die castings IS 2305 : 1988 Method for mercurous nitrate test for copper and copper alloys IS 2643 : 2005 Pipe Threads Where Pressure-Tight Joints are not Made on the

Threads - Dimensions, Tolerances and Designation 3400 (Part 2):

2003

Method of test for vulcanized rubbers : Part 2 : rubber, valcanized or thermoplastic – determination of hardness (hardness between 10 IHRD and 100 IHRD)

3400 (Part 4) : 1987

Method of test for vulcanized rubbers : Part 4 Accelerated ageing (second revision)

4218 (Part 1): 2001

ISO general purpose metric screw threads : Part 1 Basic profiles (second revision)

4218 (Part 2): 2001

ISO general purpose metric screw threads : Part 2 General plan (second revision)

4218 (Part 3): 1999

ISO general purpose metric screw threads : Part 3 Basic dimensions (second revision)

4218 (Part 4): 2001

ISO general purpose metric screw threads : Part 4 Selected sizes of screws, bolts and nuts (second revision)

5116: 1996 Domestic and commercial equipment for use with LPG – General requirements (third revision)

IS 6009 : 1970 Method for evaluation of results of accelerated corrosion test 8737:1995 Valve fittings for use with liquefied petroleum gas (LPG) cylinders of

more than 5-litre water capacity – Specification (first revision) IS 9844 : 1981 Methods of Testing Corrosion Resistance of Electroplated and

Anodized Aluminium Coatings by Neutral Salt Spray Test 14962 (Part 1):

2001 ISO general purpose screw threads – Tolerances : Part 1 Principles

and basic detail 14962 (Part 2):

2001 ISO general purpose screw threads – Tolerances : Part 2 Limits of

sizes for internal and external screw threads – medium quality 14962 (Part 3):

2001 ISO general purpose screw threads – Tolerances : Part 3 Deviations

for constructional screw threads 14962 (Part 4):

2001 ISO general purpose screw threads – Tolerances : Part 4 Limits of

sizes for hot-dip galvanized external screw threads with to mate with internal screw threads tapped with tolerance position H or G after galvanizing

14962 (Part 5): 2001

ISO general purpose screw threads – Tolerances : Part 5 Limits of sizes for hot-dip galvanized internal screw threads with to mate with hot dip galvanized external screw threads with maximum size of tolerance position ‘h’ before galvanizing

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ANNEX B

(Clause 5.9.1)

REGULATORS FITTED WITH AN EXCESS FLOW VALVE DEFINITION The excess flow valve is a device integral with the regulator which causes the shut off of the gas flow for values of rate greater than the guaranteed rate. In the case of a manual device the regulator device allowing the restoration of the flow can be a re-setting device or a valve generally appropriate for this type of regulator PERFORMANCE CHARACTERISTICS The excess flow valve shall shutoff the gas flow in all the cases of disconnection of the flexible hose or tube fitted down stream of the regulator. This device shall operate for an increase in the rate between 120% and 200% of the guaranteed rate at an angle of ±10° relative to its axis in the fixing position(s) of the regulator in the range and the rate obtained on hose or tube disconnections of minimum and maximum temperature conditions . The restoration of the gas flow shall only be possible by manual or automatic intervention when the conditions which caused the safety device to operate have disappeared. For automatic re-setting devices a maximum residual leak between 30g/h and 60g/h is permitted when the devise is in the zero flow position so as to allow re-setting. For manual re-setting devices a maximum residual leak between 15cm³/h and 200cm³/h is permitted, The presence of the device shall not modify the regulator performance. TEST METHODS Complementary tests for the regulator The performance test for the excess flow valve shall be carried out at the following operating temperatures:

iii) Max Temp : +60°±2°C ii) Min Temp : -20°±2°C

The closure caused by excess flow valve shall be obtained in the range defined between 120% and 200% of the guaranteed rate. For the endurance test the device shall be subjected to a series of 1000 cycles of opening / closing with out change in operating forces, sensitivity of positioning device and without apparent traces of pitting. This test shall be carried out at ambient temperature


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USER AND MAINTENANCE INSTRUCTIONS In addition to the regulator working instructions the manufacturer shall clearly indicate in the instructions the below information.

Do not move the cylinder during the use Close the cylinder valve in the event of operation of the excess flow valve. Only open the valve after having rectified the cause of the device operating.

For the purpose of routine test the regulator when checked the excess flow valve shall shut off the gas flow in all the cases of disconnection of the flexible hose fitted down stream of the regulator.

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ANNEX C (Clause 4.3.4)

BURSTING AND PULL OUT TEST OF DIAPHRAGM IN AN ASSEMBLED

REGULATOR C-1 GENERAL C-1.1 The test is designed to give a practical result on assembled regulator, and is intended as simple check method which may be applied by the regulator manufacturer to diaphragm material which will usually have been previously tested by some other method (for example, Mullins test) by the supplier. C-1.2 The test takes the form of a simple application of pressure (air or Nitrogen is suitable) through the outlet connection the underside of the diaphragm mounted in a regulator in fully assembled condition (that is, as it would be supplied by the manufacturer to a buyer). C-2 TEST RIG C-2.1 The outlet of the assembled regulator is connected to a supply of air or Nitrogen. C-2.2 A gauge is incorporated in the test rig between the air or Nitrogen supply and the regulator to indicate the applied pressure.

C-3 TEST METHOD The pressure is applied at approximately 78 kPa (0.8 kgf/cm2) per second up to the level specified in 4.3.4 and maintained for 120 s.


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ANNEX D (Clauses 4.3.5 and 4.4.2)

IMMERSION TEST (RESISTANCE TO HYDROCARBONS

D-1 GENERAL The test is designed to evaluate the rubber material vis-à-vis its resistance to hydrocarbons D-2 PROCEDURE Weigh the sample. Wo prior to test. Immerse the same in pentane or test gas (as defined in Annex D) maintained at a temperature of 20±5oC for 72 h. Remove the sample and expose it to atmosphere. After 5 min, weigh the sample W1. Next, let it stay exposed to atmosphere for 24 h and weigh W2 and calculate the following:

a) Percentage of test gas absorbed = ( W1 - W2 ) / Wo X 100, and

b) Percentage of matter extracted = (W0 – W2) / W0 X 100 D-3 The results of the above test shall be in accordance with values as given below:

Component Extractable PercentAbsorbed

Percent Diaphragm 10 10 Valve pad 5 10 Seal 20 20 Note – It is permitted to wipe clean the component after removal from immersion

ANNEX E (Clause 4.4.4)

TEST GAS COMPOSITION

E-1 The test gas is nominally 50 percent propane. In practice, this test gas shall conform to the following specification: a) The total content of propane shall not be less than 45 mols and not greater than 55 mols percent, b) The total content of C2 hydrocarbons shall not exceed one mol percent, and,

c) The total content of C4 hydro carbons shall not exceed 2 mols percent. E-2 Alternatively commercial liquefied petroleum gas (LPG) may be used as test gas.

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ANNEX F (Clause 8.10.1)

CYCLE TEST (ENDURANCE TEST)

F-1 The purpose of the test is to evaluate the quality of various flexibles, such as valve pad, diaphragm and spring, vis-à-vis retention of critical properties relevant to function, resistance to deformation/degradation, loss of flexibility under conditions of flexing and unflexing. This test does not purport to check any mechanical requirements of the construction /assembly and should not be taken as representative of actual service conditions and could introduce improper parameters of assessment of non-flexibles. The test should relate only to the flexibles referred to above. F-2 The regulator is mounted on a valve (whose outlet matches with the inlet of the regulator). The outlet of the regulator is connected to a system which will indicate flow or lack of it (that is, a burner, flow meter or orifice in parallel with a pressure indicating device such as a manometer column). Air/gas is introduced into the regulator at an appropriate pressure in such a manner that the diaphragm gets flexed and the valve pad is held on its seat for a minimum of one second, after which the inlet is shut off and the air/gas is vented via the outlet of the regulator to atmosphere. F-2.1 One example of a set up to carry out this test id to install quick acting valves upstream and downstream of the regulator, wherein the downstream valve exhausts to atmosphere. The valves are connected to a suitable time switch so that as one opens, the other closes; with a complete cycle time of approximately 5 seconds. F-2.2 Any other set up producing equivalent conditions and achieving the same objectives would be acceptable. F-3 After completion of the test mentioned above (see F-2), the regulator shall meet the requirements of soundness test as in 6.2, hydrostatic test as in 6.3 and performance as in 8.9.1. However, with the static (lock up) pressure not exceeding 110 percent of that allowable in relevant lock up clause. Note – If the tests are carried out using LPG vapour as test medium, sufficient precaution should be

ensured to vent inflammable gas to environments where there should be no danger of fire. Alternatively, the venting could be done via gas burning devices.


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ANNEX G

(Clauses 8.10.2 and 8.10.3)

LOW TEMPERATURE AND HIGH TEMPERATURE TESTS

G-1 LOW TEMPERATURE TEST G-1.1 A fully assembled regulator, set as in 8.9 is placed in a sealed container and this container is immersed in a bath of any convenient fluid (namely, methanol or any suitable freezing mixture like salt + ice + calcium carbide) cooled to a steady temperature of -20oC and maintained at this temperature by some reliable means (by additions of dry ice). It is kept immersed long enough for the complete assembly to attain -20oC (10 min) after which it is removed and exposed to the atmosphere so that the assemble returns to ambient conditions. It is then tested in accordance with 8.9 for performance.

Note – Care should be taken to prevent the cooling fluid entering the assembly or of moisture condensing inside. This may be avoided by ensuring that the sealed container lid opened only after the assembly attains ambient conditions.

G-2 HIGH TEMPARATURE TEST G-2.1 A fully assembled regulator set as in 8.9 is placed in a sealed container and this container if placed in a bath of water heated to a steady temperature of 65oC. It is kept immersed long enough for the complete assembly to attain 65oC (10 min) after which it is removed and exposed to atmosphere so that the assembly returns to ambient conditions. It is then tested in accordance with 8.9 for performance.

Note – Care should be taken to prevent the bath water from entering the assembly, or of moisture forming inside. This may be avoided by ensuring that the sealed container is opened only after the assembly attains ambient conditions. Also, air shall not be forced through the assembly in an attempt to accelerate cooling as this is likely to result in condensation of moisture inside the assembly.

ANNEX H (Clause 4.2.1)

METHOD OF TEST FOR ADHESION OF PAINT

A square measuring 12 to 15mm sides shall be marked on plain surface (not having raised or sunk markings) of randomly selected specimen from the lot of painted or powder coated components. Cross lines at a distance of 1 to 1.5mm and inched at approximately 120o angle with each other shall be described over the marked portion with a sharp pointed instrument. cellulose tape shall be applied over this portion and left for 2 min after which is shall be jerked free from the surface under test. If any portions of the matrix are found adhering to the tape, the specimen shall be deemed to have failed test.


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Draft For Comments Only

FLASH BACK ARRESTOR (FLAME ARRESTOR) – SPECIFICATION (Revision of IS 11006)

ICS 13.230; 23.040.80

________________________________________________________________________ Not to be reproduced without the permission of Last date for receipt of BIS or used as a STANDARD comments is: 31 Oct 2008 ________________________________________________________________________ FOREWORD Adoption clause will be added later on. The main purpose of the flash back arrestors or flame arrestors is to prevent the propagation of flame through it or any thing that is desired to be protected like storage tank, pipe line or generator. A flash back arrestor or flame arrestor in investigated for the installation for which it is designed and for a general application. This standard was first published in 1984. This revision is taken to include the following tests:

1) Flash back resistance; 2) Gas flow measurement. 3) Pressure cutout; 4) Pressure resistance; 5) Reverse flow; and 6) Temperature cutoff.

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 IS 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. 1 SCOPE This specification covers flash back arrestors for use in delivery pipe lines, acetylene generators, gas, petroleum, oil and gasoline or liquefied petroleum storage and or piping system and welding and cutting systems. 2 TERMINOLOGY 2.1 Flash Back Arrestor -It is a device to stop or arrest or prevent the return of the flame which can result in an explosion or of the blow back of the oxygenated gas from damaging whatever it is intended to protect. These are device which incorporates two or more of the safety functions.


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2.2 These are further divided into two categories

i) Hydraulic Back Pressure Valve Or Wet Type Flash Back Arrestor - It

is a flash back arrestor where the sealing is done by the help of liquid. ii) Dry Type Flash Back Arrestor – It is a device where the sealing is done

by help of sintered metal or perforated discs or ceramic cartridge or by any means other than employing a liquid to arrest the flame.

2.3 Safety Seals - The flame arrestors or flash back arrestors are at times also referred as safety seals.

2.4 Safety Relief Device – It is a device intended to prevent rupture of the flame arrestor due to sudden built in pressure which can be in a form of safety valve, bursting disc or liquid seals connected to atmosphere.

2.5 Deflagration - It is a flame that travels into the unburnt gas at almost any velocity less than sonic.

2.6 Detonation - It is a flame that travels into the unburnt gas at a rate that is above the speed of sound.

2.7 Flash Back - It is the return of the flame into an apparatus or line and its propagation against the flow of the gas.

2.8 Maximum Operating Pressure – Maximum Pressure to which the equipment may be put in service. 2.9 Non Return Valve - It prevents the flow to return from the down stream side . . 2.10 Pressure –Sensitive Cut – Off Valve - Device which stops the gas flow in the normal flow direction in the event of a back pressure wave from the downstream side.

2.11 Temperature – Sensitive Cut – Off Valve – Device which stops the gas flow in the normal flow direction when a predetermined temperature is exceeded. 2.12 Flame Arrestors - Devise which quenches a flame.

3 MATERIAL 3.1 The device shall be of a metal, resistant to corrosion or chemical reaction under condition of use. Where corrosion cannot be avoided suitable corrosion allowance shall be included in its thickness.

3.2 Gaskets shall be made of compressed asbestos fiber or metal spiral wound type or synthetic rubber which is compatible with the process gas.

4 CASING

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4.1 The casing or housing shall be of non-fragmenting type made of forged steel, carbon steel or alloy steel pipe tube or plates, cast stainless steel, forged or extruded non – ferrous material or equivalent.

The casing or housing shall withstand the internal hydraulic pressure which is equal to ten times its maximum working pressure or 60 bars which ever is higher, without any permanent deformation or leaks when applied for a minimum period of 5 min.

4.2 The casing and the flat joints in a device or a flat surface in the device shall be free from any burrs or irregular surface or defects and shall preferably be machined to a fine finish.

5 FLANGED OR THREADED CONNECTIONS The device shall have provisions for flanged or threaded connection to standard pipe which shall conform to relevant Standards for pressure rating to withstand the hydrostatic tests.

6 FLAME ARRESTOR SEALING MEDIUM 6.1 The sealing medium can be a liquid like water, or sintered or perforated metal or ceramic cartridge having good thermal conductivity, high porosity, large surface area and small pore size and shall be so constructed that, it quenches the flame as 6.1. 6.2 The sealing medium shall be such that it does not react with the gas with which it is intended to be used and is safe for use under the operation condition. 6.3 Where a device relies wholly or partly on liquid sealing medium, means shall be provided for readily filling, observing and adjusting the level of the medium without introducing air into the system during operation.

7 VENT PIPE Vent Pipe or blow of outlet when provided shall be designed and constructed to prevent any choking or obstruction which could interfere with adequate venting. The discharge shall be safely dispersed.

8 SAFETY VALVES / BURSTING DISCS If safety valves and bursting discs are provided they shall be designed for full flow type , and set at a pressure not more than 10 per cent of the working pressure.

9 INTERNAL PARTS The internal parts of the device shall be so constructed that the condition of the internal parts can be examined and maintained if any maintenance is required.

10 REQUIREMENTS 10.1 General


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Requirement of each safety device varies depending on its function and combination of these devices. A summary of requirements and tests are summarized in Table 2. 10.2 Internal Gas tightness

Where internal gas tightness is required in this standard the leakage rate shall not exceed 50 cm2/h for devices with a connection internal bore (diameter) less than 11mm or 0.41 d2 for larger diameters (see 11.5 ).

NOTE The value 0. 41 d2 is the flow in cm2 /h where d is the internal bore (diameter) in mm of the largest connection of the device. Alternatively at 10 percent of maximum operating pressure reverse flow it should have no leakage

10.3 Flame Arrestor

Flame arrestors shall quench flashbacks when tested in accordance with 11.6. 10.4 Flame Arrestor With Non-Return Valve

Flame arrestor with non-return valve shall quench flashbacks when tested in accordance with 11.6 and shall not allow the reverse flow of gases when tested in accordance with 11.5.2 both before and after the flashback test.

10.5 Flame Arrestor With Temperature Sensitive Cut-Off Valve

Flame arrestor with temperature-sensitive cut-off-valve shall quench flashbacks when tested in accordance with 11.6 and shall stop the gas flow before the upstream gas is ignited when tested in accordance with 11.7.

It shall not be possible to reset the temperature sensitive cut off valve If the temperature-sensitive cut-off valve operates before the fifth flashback in test and the flame is not transmitted upstream the unit shall be considered to meet the flashback test requirement, but test shall still be carried out on a new unit. 10.6 Gas Flow

The gas flow at maximum operating pressure for which the device with all its combinations shall operate should be the flow in Cubic meters per hour at a maximum pressure drop across the device by 10 percent of the maximum operating pressure.

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Fig. 1 Typical Wet Type Flash Back Arrestor With Non-Return Valve And

Flame Arrestor

Fig 2 Typical Flash Back Arrestor Having Non-Return Valve, Flame Arrestor, And Temperature Sensitive Cut Off Valve

10.7 Flame Arrestor With Pressure-Sensitive Cut-Off Valve

Flame arrestor with pressure-sensitive cut-off valve shall quench flashbacks when tested in accordance with 11.6 and the pressure-sensitive cut-off valve shall remain closed until manually reset.

The pressure-sensitive cut-off valve shall be reset after each flashback during test as per 11.6. Flame arrestor with pressure-sensitive cut-off valve shall also stop the gas flow when tested in accordance with 11.9 both before and after completing the flash back test. .


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Fig. 3 Typical Flash Back Arrestor Having Non-Return Valve, Flame Arrestor And

Pressure Sensitive Cut Off Valve

11 METHODS FOR TYPE TESTING 11.1 General

The test methods in this section are not intended as production inspection tests, but are to be applied to sample devices to be tested for compliance with this standard. Tests shall be carried on new devices with all safety functions operational as designed. 11.2 Accuracy of Pressure and Flow Measurements

The allowable total error of the measured values is as follows:

Flow + 10% Pressure + 3% All flows and pressures shall be expressed in standard atmospheric conditions in accordance with relevant Indian Standards. All pressure valves are given in gauge pressure, expressed in bars.

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11.3 Test Gases

Unless otherwise stated, tests shall be carried out at ambient pressure conditions and at (27 + 5)0C with air or nitrogen free from oil and grease.

Air is considered as oil-free if it comprises:

a) A mass fraction of oil vapour of less than 5 x 10-6; and b) Less than 1mg/m3 of suspended droplets.

In all cases, tests shall be carried out with dry gas with maximum moisture content corresponding to a dew point of 0oC.

Safety devices for hydrogen shall be tested with hydrogen or helium for the gas tightness test only.

11.4 Pressure Resistance Test

Conformity with the requirements of 4.1 shall be checked by means of a hydraulic pressure test on one sample. No other tests shall be carried out on the sample either before or after this test nor shall the sample tested be used for any other purposes. 11.5 Non-Return Valve Test 11.5.1 General

Conformity with the requirements of 10.4 shall be checked on five samples as follows. Before proceeding with this test, pass the test gas through the device in the normal direction of flow for 5 sec. to operate the valve. Connect the downstream side of the device under test to a gas source, with the upstream side at atmospheric pressure and connected to a leak detection device. Proceed to pressurize in the reverse direction according to 11.5.2. For the tests, the samples shall be installed in the most disadvantageous position (gravity acting to open the valve).

11.5.2 Tests with Reverse Flow of Gas

Pressurise the device in the reverse direction as follows:

a) Increase the back- pressure at a rate of 6mbar/min up to 10 percentage of

the maximum working pressure; b) Increase the back-pressure within 1 s from 0 to maximum operating pressure.

The maximum reverse flow during the period of reverse pressure application and for 1 min. afterwards shall meet the requirements of 10.2. When the device incorporates a pressure-sensitive cut-off valve, it is acceptable for the valve to operate during the non-return valve test.

11.6 Flame Arrestor Test

A diagram of the test equipment is shown in Fig. 5.


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The gas mixture and pressure for testing flame arrestors depend on the gas application and the maximum operating pressure specified by the manufacturer (see Table 2). Flame arrestors shall each be subjected to five flashbacks with a static mixture of fuel gas and oxygen given in Table 1.

Between two flash backs a sufficient delay is required to return to the initial conditions.

Each flame arrestor shall prevent the upstream gas igniting for all five flashbacks.

WARNING - All precautions shall be taken to protect personnel from the effect of fire and explosion.

TABLE -1

(Clause 11.6)

Gas application Test pressure

Test mixture volume fraction in (%) of fuel gas in oxygen.

Acetylene Oxygen Air

Maximum operating pressure

32 % to 35 % Acetylene.

LPG Maximum operating pressure

13 % to 15 % Propane.

Hydrogen Maximum operating pressure

40 % to 50 % Hydrogen

Other fuel gases Maximum operating pressure

80 % to 90 % of stochiometric mixture.

for connection internal diameter of pipe should be equal to outlet size of device

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Fig. 4 Test Equipment For Testing Efficiency Of Flame Arrestor 11.7 Temperature –Sensitive Cut- Off Valve Test A diagram of the test equipment is shone in Figure. This test is to be carried out on one new unit. The fuel gas used for the test shall be as given in Table 3. Adjust the fuel gas valve so that a flame at the outlet side of the steel tube is stable. Slowly open the oxygen valve until the flame retreats into the tube and device. The cut-off valve shall automatically cut off the gas flow before the upstream gas is ignited.. When the device incorporates a pressure sensitive cut-off valve which operates during the test, the pressure sensitive cut-off valve shall be disabled and the test repeated.

Fig. 5 Test Equipment For Testing Temperature Sensitive Cut- Off

Valve 11.8 Pressure-Sensitive Cut-Off Valve Test

The requirements specified in 10.6 shall be checked on five samples as follows. Connect the downstream side of the device under test to a gas source, with the upstream side open to the atmosphere. Progressively increase the downstream pressure to check that the device is actuated by a pressure less than or equal to 1200 mbar.

11.9 Gas Flow Measurement Test


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The gas flow characteristic for each device can be measured by means of a performance test using the circuit shown in Fig. 6. With the device discharging directly to the atmosphere, the upstream pressure should progressively be increased to the maximum operating pressure p max, and the gas flow rate and pressure drop measured at different intermediate pressure preferably at 0.25, 0.5, 0.75 of maximum operating pressure and at maximum operating pressure..

The gas to be used for this test can be dry air or the gas for which the device is intended. The average of the results obtained from 5 samples shall be considered to be the nominal value. The flow rates of the 5 samples should not diverge by more than 10 percent.

Fig. 6 Typical Example of Circuit for Gas Flow Measurement

TABLE -2 (Clause 10.1 and 11.6)

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Safety Device

function Requirements (Clause No.)

Tests (Clause No.)

Number of devises required for each test

Total number of devises required

Flame arrestor 4.1 10.3 10.6

11.6 Flame arrestor test 11.4Pressure resistance 11.9Gas flow measurement

5 1 5

7

Flame arrestor+ non-return valve

10.2 4.1 10.4 10.6

11.4Pressure resistance 11.5Reverse flow 11.6Flashback resistance 11.5Reverse flow 11.9Gas flow measurement

1 5 5 5 5

7

Flame arrestor + non-return valve+ temperature sensitive cut off valve

10.2 4.1 10.5 10.6

11.4Pressure resistance 11.6Flashback resistance 11.7Temperature cut-off 11.9Gas flow measurement

1 5 1a

5

8

Flame arrestor + non-return valve + pressure sensitive cut off valve

10.2 4.1 10.4 10.5 10.6

11.4Pressure resistance 11.5Reverse flow 11.6Flashback resistance 11.5Reverse flow 11.8Pressure cut off 11.9Gas flow measurement

1 5 5 5 5 5

8

Flame arrestor+ non-return valve+ temperature sensitive cut off valve+ pressure sensitive cut off valve

10.2 4.1 10.4 10.5. 10.7

11.4Pressure resistance 11.5Reverse flow 11.8Pressure cut – off 11.6Flashback resistance 11.5Reverse flow 11.8Pressure cut off 11.7Temperature cut-off

1 5 5 5 5 5 1a

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a Use a new device for this test. Do not use for any other test

12 MANUFACTURER’S TEST

The following test should be carried out by the manufacturer on flash back arrestors confirming to this standard:

a) Test with reverse flow of gas for each device; b) Pressure resistance test on one sample out of each lot of 100 samples; and c) Flame arrestor test on one sample out of each lot of 100 samples.

13 MANUFACTURERS INSTRUCTIONS When distributed, the safety device shall be accompanied by the manufacturers instructions which shall contain, as a minimum, the following information:


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a) The function of the safety device; b) Operational and performance data (maximum working pressure, gas flow

characteristics, see Annex A);

c) Permissible types of gas; d) An explanation of the abbreviations marked on the device ;

e) Instruction for installation of equipment - the method of installing these devices (types selected, order of installation, etc.) varies with operating conditions. It is essential to follow the manufacturers instructions regarding installation and operation to ensure that the overall pressure

drop due to the combination is as low as possible; f) Procedures to be carried out prior to operation; g) Procedure for safe operation; h) Instruction in case of malfunctioning; and i) Recommendation for inspection, testing and maintenance.

14 Marking 14.1 A flash back arrestor shall be clearly and permanently marked with the following:

a) Manufacturer’s name or trade-mark; b) Number of this standard; c) Serial number; d) Direction of nominal flow; e) Name of gas or its abbreviation as given in Annex A; f) Maximum operating pressure in bars; and g) Safety functions as given in Annex B.

14.2 BIS Certification Marking Each flash back arrestor may also be marked with the Standard Mark. 14.2.1 The use of the Standard Mark is governed by the provisions of Bureau of Indian Standards Act, 1986 and the Rules and Regulations made thereunder. The details of conditions under which a licence for the use of the Standard Mark may be granted to manufacturers or producers, may be obtained from the Bureau of Indian Standards.

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ANNEX A

(Clause 14.1)

For marking following abbreviation of gases shall be used.

Acetylene A Coal gas or Town gas C Compressed air D Ethylene E Hydrogen H Methane or natural gas M Oxygen O LPG or propane P

ANNEX B (Clause 14.1)

The safety functions shall be marked and enclosed in boxes as follows:

Wet or dry type W or D

Flame arrestor F

Non-return valve N

Pressure sensitive cut-off valve P Temperature sensitive cut-off valve T

In case of multiple function the number of boxes will be added to one another e.g.

Acetylene, Dry type, Flame arrestor, Non-return valve will be A DFN If, in addition, a colour coding band is used, red shall be used for fuel gases, blue for oxygen and for others black

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