Standard No.:	GB 35208-2025
English Name:	Overflow cutoff valves for liquefied petroleum gas cylinders
Chinese Name:	液化石油气瓶过流切断阀
Professional Classification:	GB    National Standard
Source Content Issued by:	SAMR;SAC
Issued on:	2025-12-02
Implemented on:	2026-7-1
Status:	to be valid
Superseding:	GB/T 35208-2017 Self-closing valves for LPG cylinders
Target Language:	English
File Format:	PDF
Word Count:	12000 words
Translation Price(USD):	360.0
Delivery:	via email in 1~5 business day

GB 35208-2025 Overflow cutoff valves for liquefied petroleum gas cylinders English, Anglais, Englisch, Inglés, えいご This is a draft translation for reference among interesting stakeholders. The finalized translation (passing through draft translation, self-check, revision and verification) will be delivered upon being ordered. ICS CCS H National Standard of the People's Republic of China ‌GB 35208-2025 Replaces GB 35208-2017 Overflow cutoff valves for liquefied petroleum gas cylinders 液化石油气瓶过流切断阀 Issue date: 2025-12-02 Implementation date: 2027-01-01 Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China the Standardization Administration of the People's Republic of China Contents Foreword 1 Scope 2 Normative References 3 Terms and Definitions 4 Model Designation 5 Design Requirements 6 Technical Requirements 6.1 Material Requirements 6.2 Process Requirements 6.3 Performance Requirements 7 Test and Inspection Methods 7.1 General Rules 7.2 Mechanical Property Testing and Chemical Composition Analysis Methods for Valve Body Metal Materials 7.3 Performance Testing of Non-metallic Seal Materials 7.4 Dimensional Inspection 7.5 Appearance Inspection 7.6 Inlet/Outlet Thread Inspection 7.7 Weight Inspection 7.8 Temperature Resistance Test 7.9 Cut-off Performance Test of Excess Flow Shut-off Device 7.10 Durability Test of Excess Flow Shut-off Device 7.11 Sealing Performance Test (Closing) 7.12 Opening and Closing Performance Test 7.13 Vacuum Resistance Test 7.14 Durability Test of Straight Valve Outlet 7.15 Disassembly Inspection 8 Inspection Rules 8.1 Material Inspection 8.2 Factory Inspection 8.3 Type Testing 8.4 Inspection Items 9 Marking, Packaging, Storage and Transport 9.1 Marking 9.2 Packaging 9.3 Public Website and Factory Documentation 9.4 Storage and Transport 10 Implementation of the Standard Appendix A (Normative) Basic Dimensions of Straight Valves, Outlet Structure, and Dimensions of Connector Fittings A.1 Basic Dimensions of Straight Valves A.2 Structure Type and Dimensions of Straight Valve Outlet A.3 Type and Dimensions of Rubber Sealing Ring for Straight Valves A.4 Structure Type and Dimensions of Straight Valve Outlet Connector Fitting Bibliography 1 Scope This document specifies the model designation, design requirements, technical requirements, inspection and test methods, inspection rules, marking, packaging, storage and transport for angle valves and straight valves for liquefied petroleum gas cylinders with excess flow shut-off function (hereinafter referred to as "valves"). This document applies to cylinder valves used within an ambient temperature range of -40℃ to 60℃, with a nominal working pressure not exceeding 2.5 MPa, a volume not exceeding 150 L, and media conforming to GB 11174. This document does not apply to vehicle liquefied petroleum gas cylinder valves. 2 Normative References The following documents contain provisions that, through normative reference in this text, constitute essential provisions of this document. For dated references, only the edition corresponding to that date applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 197 General purpose metric screw threads — Tolerances GB/T 1184 Geometrical tolerancing — Tolerances of form, orientation, runout and location for features without individual tolerance indications GB/T 1804 General tolerances — Tolerances for linear and angular dimensions without individual tolerance indications GB/T 3934 Gauges for general purpose metric screw threads — Technical requirements GB 7512 Valves for liquefied petroleum gas cylinders GB/T 8335 Special threads for gas cylinders GB/T 8336 Gauges for special threads for gas cylinders GB/T 13005 Terminology for gas cylinders GB/T 45439 Technical specification for traceability QR code application for gas cylinders and gas cylinder valves GB/T 46086 Liquefied petroleum gas cylinders — Fully-wrapped composite cylinders with high density polyethylene inner liner and glass fiber reinforcement 3 Terms and Definitions For the purposes of this document, the terms and definitions given in GB 7512, GB/T 13005, and the following apply. 3.1 reference state Dry gas state at a temperature of 15℃ and an absolute pressure of 101.325 kPa. [SOURCE: GB/T 16411—2023, 3.1] 3.2 rated cut-off flow The maximum volume flow rate, converted to the reference state of 20Y reference gas, passing through the outlet port of the valve under a pressure of 0.05 MPa. Note 1: 20Y reference gas refers to liquefied petroleum gas 20Y specification standard gas conforming to GB/T 13611. Note 2: The unit is cubic meters per hour (m³/h). 4 Model Designation The model designation and representation method for the valve are as follows: 5 Design Requirements 5.1The basic dimensions of angle valves shall comply with the provisions of GB 7512. The basic dimensions of straight valves shall comply with the provisions of Appendix A. 5.2The structural design of the valve shall ensure its safety within the design service life. 5.3The excess flow shut-off device shall be designed as an integral part of the valve body and shall not be externally connected outside the valve body. 5.4The closing mechanism of the excess flow shut-off device shall be designed to be either fully open or fully closed state, with no intermediate states allowed. 5.5The excess flow shut-off device shall be designed with a manually operated mechanical reset mechanism. The reset mechanism shall be designed as an integral part of the valve body. Reset mechanisms with independent reset buttons shall be protected. 5.6For valves used on liquefied petroleum gas steel cylinders, the inlet threads shall be tapered threads. The thread for vapor phase cylinder valves shall be PZ27.8, and for liquid phase valves shall be PZ39.0. Their thread dimensions and manufacturing accuracy shall conform to GB/T 8335. For valves used on liquefied petroleum gas fully-wrapped composite cylinders with plastic inner liner, the inlet threads shall be straight threads. The thread for vapor phase cylinder valves shall be M26×1.5. Its thread dimensions and manufacturing accuracy shall conform to GB/T 197. 5.7The outlet threads of angle valves shall comply with the provisions of GB 7512. 5.8The outlet diameter of straight valves shall be φ20 mm. The outlet type, connection fittings, and the type, dimensions, and accuracy of seals shall comply with the requirements in Appendix A. 5.9The tail of liquid phase cylinder valves shall have threads for connecting the liquid phase pipe. The connection thread is M22×1.5, and its dimensions and manufacturing accuracy shall conform to GB/T 197. 5.10The structural design requirements for smart valves shall also comply with the provisions of GB 7512. 5.11The design service life of the valve shall be not less than 5 years. For fully-wrapped composite cylinders with plastic inner liner, valves with a design service life of not less than 13 years may be selected. The selected valves shall meet the requirements of GB/T 46086. 6 Technical Requirements 6.1 Material Requirements 6.1.1 General Requirements 6.1.1.1 Materials of the valve in contact with liquefied petroleum gas under specified operating conditions shall meet media compatibility requirements. 6.1.1.2 Materials for the valve body and main metal components shall comply with the provisions of GB 7512.