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
BIS or used as a STANDARD
Last date for receipt of
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)
ii)
iii)
iv)
v)
Figures for outlet threaded connection incorporated;
Material clause has been modified, and
Number of cycles in cycle test modified
Requirements for excess flow valve incorporated;
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.
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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
2
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
IRHD
30
28.9
40
39.5
50
50
60
60.5
70
70
80
80
90
89.5
100
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.
4
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)
b)
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).
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.
6
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)
b)
c)
Does not easily get clogged/blocked,
The accidental entry of foreign matter is minimized, and
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)
2)
3)
b)
a torque of at least 30 N.m in one direction (verification not required
for one piece connection and for freely rotating connections);
a bending moment of 10 N.m;
a tensile strength test of 2 000 N (verification not required for one
piece connection).
Threaded connections
4)
5)
6)
a torque of at least 30 N.m in both directions (verification not required
for freely rotating connections);
a bending moment of 10 N (not required for one piece connection);
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)
2)
of at least 20 N.m for non-threaded hose outlet connections (15 N.m
for quick coupling connections);
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
Commercial
Butane
0.5 – 17
17.0
100 – 10
0
Range of outlet
pressure mm of
W.C.
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
Air
120 RVP Butane/ Propane
mixture
Butane
Natural gas
Propane
By
0.707
1.290
0.808
0.75
1.333
To obtain flow of
Butane
Natural gas
Propane
120 RVP Butane/ Propane mixture
Air
1.414
1.826
1.140
0.775
0.547
0.625
1.237
0.874
1.598
Air
Natural gas
Propane
Air
Butane
Propane
Air
Butane
Natural gas
The above data serves as a guide also in cases where the percentage composition of
constituents in an LPG mixture are known.
10
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-tubemanometer 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)
ii)
Regulators with threaded connections, the connection shall be mounted on its
valve as indicated in the table 5;
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)
b)
c)
d)
e)
f)
Diaphragm material (4.3);
Valve pad material (4.4);
Hydrostatic test (6.3);
Body (5.7.2);
Low and high temperature tests (8.10.2 and 8.10.3); and
Mechanical strength of connection (8.11).
10.2 Routine tests
The following shall be carried out as routine tests:
a)
b)
Pneumatic test (6.2 and 6.4); and
Chatter and performance test (8.9)
11 MARKING
11.1 A Regulator shall be clearly and permanently marked with the following:
a)
b)
c)
d)
Manufacturer’s name or trade mark;
Month and year of manufacture, for example 12-08 for December 2008;
Rated capacity in m3/h of gas designed for;
Number of this standard;
e)
f)
Any other markings agreed to between the purchaser and the manufacturer; and
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)
Zinc base alloy die castings
Method for mercurous nitrate test for copper and copper alloys
Pipe Threads Where Pressure-Tight Joints are not Made on the
Threads - Dimensions, Tolerances and Designation
Method of test for vulcanized rubbers : Part 2 : rubber, valcanized or
thermoplastic – determination of hardness (hardness between 10 IHRD
and 100 IHRD)
Method of test for vulcanized rubbers : Part 4 Accelerated ageing
(second revision)
ISO general purpose metric screw threads : Part 1 Basic profiles
(second revision)
ISO general purpose metric screw threads : Part 2 General plan
(second revision)
ISO general purpose metric screw threads : Part 3 Basic dimensions
(second revision)
ISO general purpose metric screw threads : Part 4 Selected sizes of
screws, bolts and nuts (second revision)
Domestic and commercial equipment for use with LPG – General
requirements (third revision)
Method for evaluation of results of accelerated corrosion test
Valve fittings for use with liquefied petroleum gas (LPG) cylinders of
more than 5-litre water capacity – Specification (first revision)
Methods of Testing Corrosion Resistance of Electroplated and
Anodized Aluminium Coatings by Neutral Salt Spray Test
ISO general purpose screw threads – Tolerances : Part 1 Principles
and basic detail
ISO general purpose screw threads – Tolerances : Part 2 Limits of
sizes for internal and external screw threads – medium quality
ISO general purpose screw threads – Tolerances : Part 3 Deviations
for constructional screw threads
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
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
IS 742 : 1981
IS 2305 : 1988
IS 2643 : 2005
3400 (Part 2):
2003
3400 (Part 4) :
1987
4218 (Part 1):
2001
4218 (Part 2):
2001
4218 (Part 3):
1999
4218 (Part 4):
2001
5116: 1996
IS 6009 : 1970
8737:1995
IS 9844 : 1981
14962 (Part 1):
2001
14962 (Part 2):
2001
14962 (Part 3):
2001
14962 (Part 4):
2001
14962 (Part 5):
2001
14
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)
ii)
Max Temp : +60°±2°C
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.
¾ Do not move the cylinder during the use
¾ Close the cylinder valve in the event of operation of the excess flow valve.
¾ 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.
16
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
Valve pad
Seal
10
5
20
10
10
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.
18
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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26
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)
2)
3)
4)
5)
6)
Flash back resistance;
Gas flow measurement.
Pressure cutout;
Pressure resistance;
Reverse flow; and
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
28
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 temperaturesensitive 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.
30
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.
32
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)
b)
A mass fraction of oil vapour of less than 5 x 10-6; and
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
Acetylene
Oxygen
Air
Test pressure
Test mixture volume
fraction in (%) of fuel
gas in oxygen.
Maximum operating
pressure
32 % to 35 %
Acetylene.
LPG
Maximum operating
pressure
13 % to 15 % Propane.
Hydrogen
Maximum operating
pressure
Maximum operating
pressure
40 % to 50 %
Hydrogen
80 % to 90 % of
stochiometric mixture.
Other fuel gases
for connection internal diameter of pipe should be equal to outlet size of device
34
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)
36
Safety Device
function
Requi
reme
nts
(Clau
se
No.)
Tests
(Clause No.)
Flame arrestor
4.1
10.3
10.6
11.6 Flame arrestor test
11.4Pressure resistance
11.9Gas flow measurement
Numbe
r of
devises
require
d for
each
test
5
1
5
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
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
7
a
Total
number of
devises
required
7
5
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)
b)
c)
Test with reverse flow of gas for each device;
Pressure resistance test on one sample out of each lot of 100 samples; and
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)
b)
c)
d)
e)
f)
g)
Manufacturer’s name or trade-mark;
Number of this standard;
Serial number;
Direction of nominal flow;
Name of gas or its abbreviation as given in Annex A;
Maximum operating pressure in bars; and
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.
38
ANNEX A
(Clause 14.1)
For marking following abbreviation of gases shall be used.
Acetylene
Coal gas or Town gas
Compressed air
Ethylene
Hydrogen
Methane or natural gas
Oxygen
LPG or propane
A
C
D
E
H
M
O
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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