GB/T 33215-2025Pressure relief devices for gas cylinders

Foreword

This document was drafted in accordance with the provisions of GB/T 1.1-2020 “Directives for standardization - Part 1: Rules for the structure and drafting of standardizing documents”.

This document replaces GB/T 33215-2016, “Pressure relief devices for gas cylinders.” Compared with GB/T 33215-2016, in addition to structural adjustments and editorial changes, the main technical changes are as follows:

a) ADD the terms and definitions of “thermally activated pressure relief device” and “vent area” (see 3.1.4 and 3.1.5 of this document);

b) ADD the description of fusible alloy activated devices (see 4.2 of this document);

c) ADD the description of glass bulb activated devices (see 4.3 of this document);

d) MODIFY the provisions that the pressure relief device shall be installed (see 5.1

of this document; 5.1 of the 2016 edition);

e) MODIFY the provisions that the pressure relief device may be exempted (see f) ADD the requirement that oxygen, nitrogen and inert gas cylinders are not equipped with pressure relief devices (see 5.5 of this document);

cryogenic insulated gas cylinders (see 6.4 of this document; 6.4 of the 2016 edition);

h) ADD the requirements for the selection of pressure relief devices for liquefied petroleum gas cylinders for vehicles, liquefied dimethyl ether cylinders for vehicles, compressed natural gas cylinders for vehicles, compressed hydrogen cylinders for vehicles, non-refillable steel welded cylinders, fiber-wound gas cylinders for breathing apparatus, seamless steel gas cylinder bundles containing liquefied gas, and other types of gas cylinders (see 6.5 ~ 6.11 of this document);

i) ADD the requirements for TPRDs installed on compressed hydrogen cylinders for vehicles (see 7.1.6 of this document);

refillable steel welded cylinders (see 7.3.2 of this document; 7.3.3 of the 2016 edition);

k) ADD the requirements for the installation of pressure relief devices for acetylene cylinders, large-volume gas cylinders for tube trailers and tube bundle containers, cryogenic insulated gas cylinders, and cylinders for metal hydride reversible hydrogen storage and release systems (see 7.3.3, 7.3.4, 7.3.5, 7.3.7, and 7.3.8 of this document).

l) ADD the requirements for the installation of bursting discs in bursting disc-fusible plug composite devices (see 7.3.9 of this document).

m) ADD the requirements for the installation of pressure relief devices for longer gas cylinders (see 7.3.10 of this document).

n) MODIFY the provisions for the value of the discharge coefficient K (see 8.2 of

this document; 8.2 of the 2016 edition).

o) ADD the provisions for the calculation of the rated capacity of pressure relief devices for compressed hydrogen cylinders for vehicles (see 8.4 of this document).

p) ADD the provisions for the calculation of the rated capacity of pressure relief devices for cylinders for tube trailers and tube bundle containers containing compressed hydrogen (see 8.5 of this document).

r) ADD the provisions for the operating temperature of TPRDs (see 9.3 of this document);

s) ADD the provisions for the marking of pressure relief devices (see 10.1 of this document).

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing authority of this document shall not be held responsible for identifying any or all such patent rights.

This document was proposed by and shall be under the jurisdiction of National Technical Committee on Gas Cylinders of Standardization Administration of China (SAC/TC 31).

Drafting organizations of this document: Dalian Boiler and Pressure Vessel Inspection and Testing Institute Co., Ltd., China Special Equipment Inspection and Research Institute, Dalian University of Technology, Beijing Tianhai Industry Co., Ltd., Sinoma Science & Technology (Suzhou) Co., Ltd., Zhejiang University, Dalian Duta Technology Safety System Co., Ltd., Shanghai Special Equipment Supervision and Inspection Technology Research Institute, Shijiazhuang Enric Gas Equipment Co., Ltd.

Main drafters of this document: Han Bing, Hu Jun, Li Bei, Huang Qianghua, Yan Xingqing, Wang Yanhui, Zhang Baoguo, Yang Minggao, Ma Xin, Li Qinan, Song Xuesi, Yu Youliang, Sun Li, Wang Hongxia, Zhu Yongjiang.

This document was first published in 2016. This is the first revision.

1 Scope

This document specifies the types and structural types, installation requirements, selection requirements, basic requirements, calculation of minimum flow capacity for safety and rated capacity, requirements for the determination of operating pressure or operating temperature, as well as marking, installation, and maintenance of pressure relief devices for gas cylinders.

This document applies to gas cylinders of various structures and types containing various gases.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

GB/T 17268 Non-refillable steel welded cylinders for industrial use GB

18428 Glass bulbs used for automatic fire extinguishing systems GB/T 42536 Assembly valve on high pressure hydrogen storage cylinder for vehicles

3 Terms, definitions, and symbols

3.1 Terms and definitions 3.1.1

A pressure relief device installed on a gas cylinder to automatically and rapidly release gas and relieve pressure in unexpectedly high-temperature environments to protect the cylinder shell from explosion.

NOTE: This includes thermally activated or pressure activated pressure relief devices.

Minimum flow rate that needs to be released, to ensure that the gas pressure inside the cylinder does not continue to rise after reaching the gas cylinder’s permissible pressure under unexpectedly high temperature conditions.

Mass of gas that can be released per unit time by a pressure relief device under specified discharge conditions.

A temperature activated pressure relief device.

NOTE: This includes fusible plug devices, fusible alloy activated devices, and glass bulb activated devices.

Geometric flow area of the minimum cross-section of a pressure relief device for discharging the medium.

3.2 Symbols

NOTE: For bursting disc devices, this is the design bursting pressure; for TPRDs, when the medium in the cylinder is liquefied gas, this is the saturated vapor pressure of the medium contained at its operating temperature; when the medium in the cylinder is compressed gas, this is the ideal pressure at its operating temperature; for safety valves, this is the rated discharge pressure.

4 Types and structural types of pressure relief devices

4.1 Fusible plug device

It is composed of a fusible alloy and a plug seat. The plug seat is directly connected to the shell or valve body. […]

4.3 Glass bulb activated device

It is composed of a glass bulb (also called a glass ball), a support, and an actuator. The actuator is connected to the valve body. When the temperature reaches a predetermined value, the glass bulb shatters, triggering the actuator to activate and release the gas within the cylinder.

4.4 Bursting disc device

It is composed of a bursting disc, a clamping ring, and fasteners (for non-refillable steel welded cylinders, the disc can be welded directly to the opening in the shell). When the gas pressure in the cylinder reaches a predetermined value, the disc ruptures, releasing the gas within the cylinder. The bursting disc device shall comply with the requirements of GB/T 16918.

4.5 Safety valve

A reversible pressure control device consisting of a valve boss, a valve disc, and a spring. […]

4.6 Bursting disc-fusible plug composite device

A pressure relief device consisting of a bursting disc and a fusible plug connected in series. The fusible plug is positioned on the discharge side of the bursting disc. When the temperature reaches a predetermined value, the gas pressure in the cylinder also reaches a predetermined value, the fusible alloy melts and the bursting disc ruptures, releasing the gas within the cylinder.

4.7 Bursting disc-safety valve composite device

A pressure relief device consisting of a bursting disc and a safety valve connected in series. When the gas pressure in the cylinder reaches a predetermined value, the bursting disc ruptures first, and the released gas opens the safety valve, releasing the gas within the cylinder.

5 Requirements for the installation of pressure relief devices

a) cylinders for on-board storage of fuel for automotive vehicle;

b) cylinders for metal hydride reversible hydrogen storage and release systems;

g) large-volume gas cylinders for tube trailers and tube bundle containers;

5.2 Gas cylinders containing pyrophoric gases (the first digit of the FTSC code in GB/T 16163 is “3”) or highly toxic gases (the second digit of the FTSC code in GB/T 16163 is “3”) shall not be equipped with pressure relief devices.

5.3 Gas cylinders containing acidic corrosive gases that form hydrohalic acids (the fourth digit of the FTSC code in GB/T 16163 is “3”) may not be equipped with pressure relief devices.

5.4 Civilian liquefied petroleum gas cylinders and civilian liquefied dimethyl ether cylinders shall not be equipped with pressure relief devices.

5.5 Nitrogen, inert gas, and oxygen cylinders (excluding fiber-wound gas cylinders) are generally not equipped with pressure relief devices.

5.6 Whether or not to install pressure relief devices on gas cylinders other than those specified above shall be proposed by the user unit and determined through consultation between the gas cylinder manufacturer and the safety accessory manufacturer.

6 Requirements for the selection of pressure relief devices

6.1 Gas cylinders containing toxic gases (the second digit of the FTSC code in GB/T 16163 is “2”) shall not be equipped with separate safety valves; gas cylinders containing low-pressure toxic gases may be equipped with fusible plug devices; gas cylinders containing high-pressure toxic gases shall use bursting disc-fusible plug composite devices. 6.2 Gas cylinders containing flammable and combustible low-pressure liquefied gases (the first digit of the FTSC code in GB/T 16163 is “2”) should be equipped with safety valves or composite devices with a safety valve. 6.3 Gas cylinders containing combustible gases that are easily decomposed or polymerized (the first digit of the FTSC code in GB/T 16163 is “5”) shall be equipped with fusible plug devices. 6.4 Cryogenic insulated gas cylinders containing liquefied natural gas and other flammable gases shall be equipped with at least two parallel safety valves; welded insulated cylinders containing other cryogenic liquefied gases shall be equipped with parallel bursting disc devices and safety valves. The bursting disc device is used to prevent the shell (liner) from bursting due to pressure buildup caused by high temperatures in a fire environment; the safety valve is used to prevent explosion caused by pressure buildup due to complete failure of the gas cylinder’s insulation. 6.5 Liquefied petroleum gas cylinders for vehicles and liquefied dimethyl ether cylinders for vehicles shall be equipped with a combination valve with a safety valve or a separate safety valve. 6.6 Compressed natural gas cylinders for vehicles with seamless steel structures and metal liner fiber-wound structures shall be equipped with bursting disc-fusible plug composite devices. 6.7 Compressed hydrogen cylinders for vehicles shall be equipped with TPRDs. 6.8 Non-refillable steel welded cylinders shall be equipped with bursting discs. 6.9 Fiber-wound gas cylinders for breathing apparatus shall be equipped with bursting discs. 6. […]

7 Basic requirements for pressure relief devices

7.1 Design requirements

7.1.4 For gas cylinders containing flammable gases, the structure and installation of the device shall ensure that the exhausted gas is discharged directly into the atmosphere, minimizing unnecessary obstruction or impact on other equipment.

7.1.6 The TPRD installed in compressed hydrogen cylinders for vehicles shall comply with the requirements of GB/T 42536, and the glass bulb shall use the products manufactured in accordance with GB 18428.

7.3 Installation requirements

7.3.5 The pressure relief device of cryogenic insulated gas cylinders shall be installed in the cylinder piping system, and its inlet pipe joint shall be directly connected to the gas phase space at the top of the inner liner. 7.3. […]