CEN/TC 23/WG 20 - Cylinder design - Fittings

This document gives a list of FTSC (fire potential, i.e. “oxidizing power and flammability”, toxicity, state of the gas, and corrosiveness) codes determined according to the relevant properties of gases and of some liquids that are transported under pressure.
It does not cover material compatibility with gases which is covered by the ISO 11114 series.

No scope available

This document specifies design, type testing and marking requirements for:
a)       cylinder valves intended to be fitted to refillable transportable gas cylinders;
b)       main valves (excluding ball valves) for bundles of cylinders;
c)        cylinder valves or main valves with integrated pressure regulator (VIPR);
NOTE 1        This includes the following specific VIPR designs where:
1)  The pressure regulating system is acting as the primary valve operating mechanism (VIPR type B). This also includes designs where closure of the primary valve operating mechanism is obtained by closing the seat of the pressure regulating mechanism.
2)  The primary valve operating mechanism is located at the low-pressure side of the pressure regulating system (VIPR type C).
d)       valves for pressure drums and tubes;
which convey compressed, liquefied or dissolved gases.
NOTE 2        Where there is no risk of ambiguity, cylinder valves, main valves, VIPRs and valves for pressure drums and tubes are addressed with the collective term “valves” within this document.
This document does not apply to
—     valves for cryogenic equipment, portable fire extinguishers and liquefied petroleum gas (LPG);
—     quick-release cylinder valves (e.g. for fire-extinguishing, explosion protection and rescue applications) - requirements for quick-release cylinder valves are specified in ISO 17871 which contains normative references to this document;
—     self-closing cylinder valves and ball valves.
NOTE 3        Requirements for valves for cryogenic vessels are specified in ISO 21011 and at a regional level, e.g. in EN 1626. Requirements for LPG valves are specified in ISO 14245 or ISO 15995. Requirements for self-closing cylinder valves are specified in ISO 17879. Requirements for ball valves are specified in ISO 23826. Requirements for valves for portable fire extinguishers at a regional level are specified, for example, in the EN 3 series.
This document only covers the function of a valve as a closure. Other functions that are possibly integrated in the valve can be covered by other standards. Such standards do however not constitute requirements according to this document.
NOTE 4        Definition of and specific requirements for VIPRs in addition to those that are given in this document are specified in ISO 22435 for industrial applications or ISO 10524-3 for medical applications. Similarly, certain specific requirements for residual pressure valves (RPV) with or without a non-return function in addition to those that are given in this document are given in ISO 15996.
NOTE 5        Certain specific requirements for valves for breathing apparatus in addition to those that are given in this document are specified at a regional level, for example, in the EN 144 series. Certain specific requirements for quick-release valves for fixed fire-fighting systems in addition to those that are given in this document are specified in ISO 16003 and at a regional level, for example, in EN 12094–4.
NOTE 6        Requirements for manufacturing tests and examinations of valves covered by this document are given in ISO 14246.

This document specifies design, type test methods, marking and instruction requirements for cylinder valves with integrated pressure regulators (VIPRs) intended to be fitted to gas cylinders, pressure drums or tubes or used as a main valve for bundles of cylinders that convey compressed, liquefied or dissolved gases.
These are requirements for VIPRs that are in addition to those given in the relevant closure standard, for example, in ISO 10297 for cylinder valves, in ISO 17871 for quick-release cylinder valves, in ISO 17879 for self-closing cylinder valves or in ISO 23826 for ball valves. For ISO 17871, these requirements are only applicable to quick-release cylinder valves types B, C, D and E.
NOTE 1        If the pressure regulating system of a VIPR is acting as the primary valve operating mechanism, it is covered by the relevant closure standard, e.g. ISO 10297, ISO 17871, ISO 17879 and ISO 23826. This also includes designs where closure of the primary valve operating mechanism of a VIPR is obtained by closing the seat of the pressure regulating system.
NOTE 2        If the primary valve operating mechanism of a VIPR is located at the low-pressure side of the pressure regulating system, it is covered by the relevant closure standard, e.g. ISO 10297, ISO 17871, ISO 17879 and ISO 23826.
NOTE 3        The term “pressure receptacle” is used within this document to cover instances where no differentiation is necessary between gas cylinders, bundles of cylinders, pressure drums and tubes.
This document does not apply to VIPRs for
a)       medical applications (see ISO 10524-3);
b)       liquefied petroleum gas (LPG);
c)        cryogenic applications.
NOTE 4        Additional requirements for a VIPR with a residual pressure device (RPD) are specified in ISO 15996.
NOTE 5        Additional requirements for pressure relief valves can exist in international/regional regulations/ standards.

This document is applicable to pin-index yoke-type valve connections for medical gas cylinders, with a working pressure up to a maximum of 200 bar or test pressure up to a maximum of 300 bar, or both.
NOTE 1        This type of connection is primarily used for small cylinders (5 l or below).
NOTE 2        In this document the unit bar is used, due to its universal use in the field of technical gases. It should, however, be noted that bar is not an SI unit, and that the corresponding SI unit for pressure is Pa (1 bar = 105 Pa = 105 N/m2).
This document specifies:
—     basic dimensions;
—     requirements for alternative designs of the yoke-type valve connections;
—     dimensions and positions for the holes and pins for the outlet connections.
It also specifies the dimensions and positions for the holes and pins for the outlet connections for gases and gas mixtures.

This document specifies the following, in order to determine the corrosiveness of gases and gas mixtures so that a suitable outlet connection can be assigned to each of them:
—    for pure gases and some liquids, a complete list indicating their corrosiveness;
—    for gas mixtures, a calculation method, in the absence of experimental data, relating to the corrosiveness of each of their components.

This document specifies requirements for the inspection and maintenance of valves [including ball valves and valves with integrated pressure regulator (VIPRs)] for:
a) refillable transportable gas cylinders;
b) cylinder bundles;
c) pressure drums and tubes;
which convey compressed, liquefied or dissolved gases.
This document does not apply to valves for liquefied petroleum gas (LPG).
NOTE       Where there is no risk of ambiguity, gas cylinders, cylinder bundles, pressure drums and tubes are addressed with the collective term “gas cylinders” within this document.
This document is applicable to valves reused at the time of the periodic inspection of gas cylinders, cylinder bundles, pressure drums and tubes, and can be applied at any other time, e.g. at a change of gas service (see ISO 11621).
This document does not apply to the routine inspection of valves, e.g. carried out at the time of a gas cylinder filling.

This document lists the best available acute-toxicity data of gases taken from a search of the current literature to allow the classification of gases and gas mixtures for toxicity by inhalation.
Scope of amendment
Changes to formula in clause 4.3

This document specifies requirements for the test apparatus and test procedure in order to apply oxygen pressure surges consistently to devices being tested for resistance to ignition by adiabatic compression and to materials for oxygen compatibility.

This document specifies the procedures and acceptance criteria for manufacturing tests and examinations (sometimes called "initial inspection and tests") of valves designed and type tested in accordance with ISO 10297.
This document is applicable to:
a) cylinder valves intended to be fitted to refillable transportable gas cylinders;
b) main valves (excluding ball valves) for cylinder bundles;
c) cylinder valves or main valves with integrated pressure regulator (VIPR);
d) valves for pressure drums and tubes.
NOTE       Where there is no risk of ambiguity, cylinder valves, main valves, VIPR and valves for pressure drums and tubes are addressed with the collective term “valves” within this document.
The principles of these manufacturing tests and examinations can be beneficially applied to cylinder valves type tested to national or International Standards other than ISO 10297.

This document specifies some gas compatibility test methods to evaluate plastic materials suitable for use in the manufacture of composite gas cylinder liners. It is also applicable to the evaluation of the suitability of plastic matrix materials used for Type 5 cylinders.
Some fluids like water, used for cylinders testing, can react positively or negatively when in contact with plastic liners. This compatibility issue is not covered by this document.

This document gives guidance on the selection and evaluation of compatibility between non-metallic materials for gas cylinders and valves and the gas contents. It is also applicable to tubes, pressure drums and bundles of cylinders.
This document covers composite and laminated materials used for gas cylinders. It does not include ceramics, glasses and adhesives.
This document considers the influence of the gas in changing the material and mechanical properties (e.g. chemical reaction or change in physical state). The basic properties of the materials, such as mechanical properties required for design purposes (normally available from the materials supplier), are not considered. Other aspects, such as quality of delivered gas, are not considered.
The compatibility data given are related to single component gases but can be applicable to gas mixtures.
This document does not apply to cryogenic fluids (this is covered in ISO 21010).

This document specifies design, type testing, marking, manufacturing tests and examinations requirements for ball valves used as:
closures of refillable transportable gas cylinders, pressure drums and tubes;
main valves for cylinder bundles;
valves for cargo transport units [e.g. trailers, battery vehicles, multi-element gas containers (MEGCs)];
which convey compressed gases, liquefied gases and dissolved gases.
NOTE 1      In this document, the term “valve” is used with the meaning of “ball valve”.
This document does not apply to ball valves for:
oxidizing gases as defined in ISO 10156;
toxic gases (i.e. gases listed in ISO 10298 having an LC50 value ≤ 5 000 ppm
acetylene for single gas cylinders, pressure drums and tubes.
NOTE 2      The reason for the exclusion of oxidizing gases is that the use of ball valves as closures of high-pressure cylinders for oxidizing gases is known to lead to specific ignition hazards that cannot reasonably be mitigated through the ball valve design or type testing. Safety hazards concern both the ball valve itself and any downstream equipment.
NOTE 3      The reason for the exclusion of acetylene for single gas cylinders, pressure drums and tubes is that the risk of an acetylene decomposition cannot reasonably be mitigated through the ball valve design or type testing.
This document does not apply to ball valves for liquefied petroleum gas (LPG), cryogenic equipment, portable fire extinguishers and cylinders for breathing apparatus.
NOTE 4      Requirements for valves for cryogenic vessels are specified in ISO 21011.
NOTE 5      Certain specific requirements for quick-release valves for fixed fire-fighting systems in addition to those that are given in this document are specified in ISO 16003.

This document specifies definitions, dimensions and tolerances of parallel screw threads of M30 x 2, M25 x 2 and M18 x 1,5, for the connection of valves to medical and industrial gas cylinders.
This document does not contain the connection requirements for:
—    mechanical strength;
—    gas tightness;
—    capability of repeated assembly and dismounting operations (this aspect is covered in ISO 13341).

ISO 10298:2018 lists the best available acute-toxicity data of gases taken from a search of the current literature to allow the classification of gases and gas mixtures for toxicity by inhalation.

This document, in conjunction with ISO 10297 and ISO 14246, specifies design, type testing, marking and manufacturing tests, and examinations requirements for quick-release cylinder valves intended to be fitted to refillable transportable gas cylinders, pressure drums and tubes which convey:
—     non-toxic;
—     non-oxidizing;
—     non-flammable; and
—     non-corrosive;
compressed or liquefied gases or extinguishing agents charged with compressed gases to be used for fire-extinguishing, explosion protection, and rescue applications.
NOTE 1  The main application of such quick-release cylinder valves is in the fire-fighting industry. However, there are other applications such as avalanche airbags, life raft inflation and similar applications.
NOTE 2  Where there is no risk of ambiguity, gas cylinders, pressure drums and tubes are addressed with the collective term "cylinders" within this document.
This document covers the function of a quick-release cylinder valve as a closure.
This document does not apply to quick-release cylinder valves for cryogenic equipment and for liquefied petroleum gas (LPG).
This document does not apply to quick-release cylinder valves if used as the main closure of portable fire extinguishers because portable fire extinguishers are not covered by transport regulation.
Quick-release cylinder valves of auxiliary refillable propellant gas cylinders used within or as part of portable fire extinguishers are covered by this document, if these cylinders are transported separately, e.g. for filling (see UN Model Regulations, Chapter 3.3, Special Provision 225, second note[1]).

This document provides requirements for the selection of safe combinations of metallic cylinder and valve materials and cylinder gas content.
The compatibility data given is related to single gases and to gas mixtures.
Seamless metallic, welded metallic and composite gas cylinders and their valves, used to contain compressed, liquefied and dissolved gases are considered.
NOTE       In this document the term "cylinder" refers to transportable pressure receptacles, which also include tubes and pressure drums.
Aspects such as the quality of delivered gas product are not considered.

This document provides specification and testing requirements for high pressure flexible hose assemblies intended to be connected to gas cylinders, bundles of cylinders or trailers (battery vehicles), and MEGCs for use when filling and emptying gas at production sites and also for customer use. This document applies to flexible hose assemblies with rated pressures up to 1 000 bar for use in the temperature range of −40 °C to +65 °C.
This document is not applicable to:
—          rubber and plastics flexible hose assemblies for welding, cutting and related processes up to 45 MPa (450 bar) for customer use (see ISO 14113);
—          high pressure flexible hose assemblies for use with medical gas systems for customer use (see ISO 21969);
—          low pressure hose assemblies for use with medical gases for customer use (see ISO 5359);
—          rubber and thermoplastic low pressure hose assemblies for welding, cutting and related processes for customer use (see ISO 3821 or ISO 12170);
—          flexible hose assemblies for cryogenic applications (see ISO 21012);
—          flexible hose assemblies for liquid petroleum gas (LPG).
NOTE       Flexible hose assembly designs which pass the type test approval described in this document can have a lower ratio of burst pressure to rated pressure than stated in other standards.

This document specifies the requirements for valve protection caps and valve guards used on cylinders for liquefied, dissolved or compressed gases.
Valve protection caps and valve guards are some of the options available to protect cylinder valves, including valves with integral pressure regulators (VIPRs) during transport.
This document is applicable to valve protection caps and valve guards which inherently provide the primary protection of a cylinder valve. It can also be used to test other equipment (e.g., handling devices) attached to cylinder packages, even in cases where the cylinder valve is inherently able to withstand damage without release of the content.
This document excludes protection devices for cylinders with a water capacity of 5 l or less and cylinders whereby the protection device is fixed by means of lugs welded or brazed to the cylinder, or is welded or brazed directly to the cylinder. This document does not cover valve protection for breathing apparatus cylinders.
NOTE    Small cylinders (e.g., medical cylinders) are commonly transported in an outer-packaging (e.g., pallet) to meet transport regulations.
This document does not specify requirements that could be necessary to enable the valve protection device to be used for lifting the cylinder.

ISO 15996:2017 specifies design, type testing and marking requirements for cylinder valves incorporating residual pressure devices, hereinafter referred to as residual pressure valves (RPVs). This document applies to the following types of RPVs:
a)    cylinder valves intended to be fitted to refillable transportable gas cylinders;
b)    main valves (excluding ball valves) for cylinder bundles;
c)    cylinder valves or main valves with integrated pressure regulator (VIPR);
d)    valves for pressure drums and tubes;
which convey compressed or liquefied gases.
NOTE          Where there is no risk of ambiguity, cylinders, pressure drums, tubes and cylinder bundles are addressed with the collective term "cylinder" within this document.
These requirements are in addition to those in ISO 10297.
For RPD stand-alone devices this document can also be applied.
ISO 15996:2017 does not apply to RPVs for portable fire extinguishers, cryogenic equipment, low pressure refrigerant gases (cylinder test pressure less than 50 bar), dissolved gases or liquefied petroleum gas (LPG).

ISO 10156:2017 specifies methods for determining whether or not a gas or gas mixture is flammable in air and whether a gas or gas mixture is more or less oxidizing than air under atmospheric conditions.
ISO 10156:2017 is intended to be used for the classification of gases and gas mixtures including the selection of gas cylinder valve outlets.
ISO 10156:2017 does not cover the safe preparation of these mixtures under pressure and at temperatures other than ambient.

ISO 17879:2017 specifies the design, type testing, marking and manufacturing tests and examinations requirements for self-closing cylinder valves intended to be fitted to refillable transportable gas cylinders which convey compressed, liquefied or dissolved gases.
NOTE 1       The main applications for such self-closing cylinder valves are in the calibration gas and beverage industries.
ISO 17879:2017 covers the function of a self-closing cylinder valve as a closure.
NOTE 2       Requirements for standard cylinder valves are given in ISO 10297. Requirements for quick-release cylinder valves are given in ISO 17871.
ISO 17879:2017 is not applicable to self-closing cylinder valves for cryogenic equipment, for portable fire extinguishers, or for liquefied petroleum gas (LPG).
NOTE 3       Requirements for valves for cryogenic vessels are specified in ISO 21011 and at a regional level, for example, in EN 1626. Requirements for valves for portable fire extinguishers at a regional level are specified, for example, in EN 3 series. Requirements for self-closing LPG cylinder valves are specified in ISO 14245.
NOTE 4       Additional requirements for pressure-relief devices might be specified in international/regional regulations/standards.

2014-04-17 GVN: Draft for // vote received in ISO/CS (see notification of 2014-04-10 in dataservice).
2013-02-22 EMA: Draft for // ENQ received in ISO/CS (see notification of 2013-02-22 in dataservice).

ISO 12209:2013 specifies the characteristics of outlet connections for gas cylinder valves for compressed breathable air gas cylinders. It states the fundamental requirements for both; the connection and its components and includes basic dimensions. Included in ISO 12209:2013 the following connections:
a) yoke type outlet connection for SCUBA use up to a maximum cylinder working pressure of 232 bar;
b) threaded type outlet connections up to a maximum cylinder working pressure of 232 bar and 300 bar; and
c) threaded type outlet connection for SCUBA use up to a maximum cylinder working pressure of 232 bar including adaptor for users to convert into a yoke type outlet.
Annex A gives the outlet connection type test procedures.
Requirements for cylinder valves (see ISO 10297) are not covered by ISO 12209:2013.
Requirements for material specifications and gas/material compatibility (see ISO 11114‑1 and ISO 11114‑2) are not covered by ISO 12209:2013.

ISO 11114-3:2010 specifies a test method to determine the autogenous ignition temperature of non-metallic materials in pressurized gaseous oxygen.
The autogenous ignition temperature is one criterion for ranking materials, and can be used to assist with the choice of materials used in the presence of gaseous oxygen.
A comprehensive bibliography of the published material on which ISO 11114-3:2010 is based is included.
It is intended that ISO 11114-3:2010 be used for the selection of non-metallic materials for gas cylinders and accessories, for example to select the materials in order to meet the requirement for type testing for oxygen compatibility of all cylinder valves for highly oxidizing gases as specified in ISO 10297.

ISO 13341:2010 specifies the procedures to be followed when connecting cylinder valves to gas cylinders. It specifically applies to all valve and cylinder combinations connected with ISO screw threads as specified in ISO 10920 and ISO 11363-1. It defines routines for inspection and preparation prior to valving for both taper and parallel screw threads.
Torque values are given for steel and aluminium gas cylinders including composite cylinders with steel or aluminium boss.
The procedures and practices specified in ISO 13341:2010 can be beneficially applied to other valve to cylinder screw thread connection systems.

This standard specifies requirements for design, manufacture and testing of safety devices to prevent over-pressurization. It does not specify where such safety devices are required, or the sizing of devices.

Selection of valve outlets for cylinders specific to pure gases for special applications.

Performance testing procedures for the connections for gas cylinder valves for use in ultra high purity service inlet connections.

This International Standard specifies types, dimensions and principles of use of gauges to be used in conjunction with the sealing systems of the parallel threads specified in Part 1. The threads themselves are gauged using GO and NOT GO gauges as described in ISO 1502.

The purpose of this part of EN 720 is to define the properties of gases on the basis of four main physical - chemical criteria, i.e. fire potential, toxicity, state of gas and corrosiveness for the purpose of the selection of suitable valve outlets.

ISO 13341:2010 specifies the procedures to be followed when connecting cylinder valves to gas cylinders. It specifically applies to all valve and cylinder combinations connected with ISO screw threads as specified in ISO 10920 and ISO 11363-1. It defines routines for inspection and preparation prior to valving for both taper and parallel screw threads.
Torque values are given for steel and aluminium gas cylinders including composite cylinders with steel or aluminium boss.
The procedures and practices specified in ISO 13341:2010 can be beneficially applied to other valve to cylinder screw thread connection systems.

ISO 14456:2015 gives a list of FTSC (fire potential, i.e. "oxidizing potential and flammability", toxicity, state of the gas, and corrosiveness) codes determined according to the relevant properties of gases and of some liquids that are transported under pressure.

ISO 10297:2014 specifies design, type testing and marking requirements for:
a)    cylinder valves intended to be fitted to refillable transportable gas cylinders;
b)    main valves (excluding ball valves) for cylinder bundles;
c)    cylinder valves or main valves with integrated pressure regulator (VIPR);
which convey compressed, liquefied or dissolved gases.
ISO 10297:2014 covers the function of a valve as a closure. It does not apply to valves for cryogenic equipment, portable fire extinguishers and liquefied petroleum gas (LPG) and quick-release valves (e.g. for fire-extinguishing, explosion protection and rescue applications), non-return valves or ball valves.

2012-06-19 EMA: Draft for // vote received in ISO/CS (see 2012-06-15 notification in dataservice).
2011-02-21 EMA: // ENQ draft received in ISO/CS (see notification from 2011-02-18 in dataservice).

ISO 22435:2007 applies to cylinder valves with integrated pressure regulators (VIPR) intended to be fitted to gas cylinders that convey compressed, liquefied or dissolved gases.

This document is applicable to pin-index yoke-type valve connections for medical gas cylinders, with a working pressure up to a maximum of 200 bar or test pressure up to a maximum of 300 bar, or both.
NOTE 1    This type of connection is primarily used for small cylinders (5 l or below).
NOTE 2    In this document the unit bar is used, due to its universal use in the field of technical gases. It should, however, be noted that bar is not an SI unit, and that the corresponding SI unit for pressure is Pa (1 bar = 105 Pa = 105 N/m2).
This document specifies:
—    basic dimensions;
—    requirements for alternative designs of the yoke-type valve connections;
—    dimensions and positions for the holes and pins for the outlet connections.
It also specifies the dimensions and positions for the holes and pins for the outlet connections for gases and gas mixtures.

ISO 13338:2017 provides:
-      for pure gases and some liquids, a complete list indicating their corrosiveness;
-      for gas mixtures, a calculation method, in the absence of experimental data, relating to the corrosiveness of each of their components;
in order to determine the corrosiveness of gases and gas mixtures on tissue so that a suitable outlet connection can be assigned to each of them.

ISO 22434:2006 specifies the requirements for the inspection and maintenance of cylinder valves, including valves with integrated pressure regulators (VIPR) (see ISO 22435).
ISO 22434:2006 may be applied to cylinder valves at the time of the periodic inspection of gas cylinders, bundles, drums and trailers, and at any other time, e.g. at change of gas service (see ISO 11621). It does not apply to routine inspection of cylinder valves carried out at the time of cylinder filling.

ISO 14246:2014 specifies the procedures and acceptance criteria for manufacturing testing and examination of cylinder valves that have been manufactured to achieve type approval.
ISO 14246:2014 is applicable to cylinder valves intended to be fitted to refillable transportable gas cylinders, main valves (excluding ball valves) for cylinder bundles and cylinder valves or main valves with integrated pressure regulator (VIPR) designed and type tested according to ISO 10297.

ISO 11114-2:2013 gives guidance in the selection and evaluation of compatibility between non-metallic materials for gas cylinders and valves and the gas contents. It also covers bundles, tubes and pressure drums.
ISO 11114-2:2013 can be helpful for composite and laminated materials used for gas cylinders.
It does not cover the subject completely and is intended to give guidance only in evaluating the compatibility of gas/material combinations.
Only the influence of the gas in changing the material and mechanical properties is considered (for example chemical reaction or change in physical state). The basic properties of the materials, such as mechanical properties, required for design purposes are normally available from the materials' supplier and are not considered.
The compatibility data given are related to single component gases but can be used to some extent for gas mixtures. Ceramics, glasses, and adhesives are not covered.
Other aspects such as quality of delivered gas are not considered.
ISO 11114-2:2013 is not intended to be used for cryogenic fluids (see ISO 21010).

2012-11-30 GVN: Draft for // vote received at ISO/CS (see notification in dataservice on 2012-11-29).

This International Standard specifies definitions, dimensions and tolerances of parallel screw threads of nominal diameter 30 mm (designated M30), 25 mm (designated M25) and 18 mm (designated M18), for the connection of valves to medical and industrial gas cylinders. This standard does not cover the connection requirements for: - mechanical tightness; - gas tightness; - capability of repeated assembly and dismounting operation. Note: This aspect is covered in ISO 13341.

ISO 17871:2015 in conjunction with ISO 10297:2014 and ISO 14246:2014 specifies design, type testing, marking and manufacturing tests, and examinations requirements for quick-release cylinder valves intended to be fitted to refillable transportable gas cylinders which convey non-toxic, non-oxidizing, and non-corrosive compressed or liquefied gases or extinguishing agents charged with compressed gases to be used for fire-extinguishing, explosion protection, and rescue applications.
ISO 17871:2015 covers the function of a quick-release cylinder valve as a closure.
ISO 17871:2015 does not apply to quick-release cylinder valves for cryogenic equipment, for portable fire extinguishers, or for liquefied petroleum gas (LPG).