GB 46770-2025 Safety specification for explosion isolation of combustible dust English, Anglais, Englisch, Inglés, えいご
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ICS 13.230
CCS H 57
National Standard of the People's Republic of China
GB/T 46770-2025
Safety specification for explosion isolation of combustible dust
可燃性粉尘隔爆安全规范
Issue date: 2025-10-31 Implementation date: 2026-05-01
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
Preface
1 Scope
2 Normative References
3 Terms and Definitions
4 Technical Requirements
4.1 Basic Requirements
4.2 Design and Selection
4.3 Explosion Isolation System Requirements
5 Installation, Use, and Maintenance
5.1 Installation and Use
5.2 Maintenance
6 Verification Methods
Appendix A (Informative) Installation and Commissioning Record Template
Appendix B (Informative) Maintenance and Care Record Template
1 Scope
This document specifies the technical requirements, installation, use, and maintenance requirements for explosion isolation of combustible dust, and describes the corresponding verification methods.
This document applies to the design, selection, installation, commissioning, and use and maintenance of explosion isolation for combustible dust.
This document does not apply to places with coal mine underground, fireworks, explosives, strong oxidants, and toxic or corrosive dust.
2 Normative References
The contents of the following documents constitute the essential clauses of this document through normative references in the text. Among them, for normative references with a specified date, only the version corresponding to that date applies to this document; for normative references without a specified date, the latest version (including all amendments) applies to this document.
GB/T 15604-2024 Terms for Dust Explosion Prevention
GB 50058 Design Code for Electrical Equipment in Explosive Hazardous Environments
3 Terms and Definitions
The terms and definitions defined in GB/T 15604-2024 and the following terms and definitions apply to this document.
3.1 Explosion Isolation
A technology that, after an explosion occurs, extinguishes the flame through physical and chemical actions, stops the propagation of the explosion, and blocks the explosion within a certain range.
[Source: GB/T 15604-2024, 6.32]
3.2 Explosion Isolation System
An explosion protection system that realizes explosion isolation by starting an explosion isolation device through a certain method.
3.3 Explosion Isolation Device
A component that directly acts on the flame and pressure wave to realize explosion isolation.
Note: The explosion isolation device is a component of the explosion isolation system.
3.4 Active Explosion Isolation System
An explosion isolation system that stops the propagation of the explosion and blocks the explosion within a certain range by triggering the explosion isolation device through a detector and a controller.
Note: The detector generally uses optical sensors and/or pressure sensors.
3.5 Passive Explosion Isolation System
An explosion isolation system that stops the propagation of the explosion and blocks the explosion within a certain range by relying on the power of the dust explosion shock wave to trigger the explosion isolation device.
3.6 Explosion Isolation Flap Valve
A valve that can close by its own gravity when the airflow in the pipeline is affected by the dust explosion, thus preventing the propagation of the explosion.
3.7 Explosion Diverter
A mechanical device generally installed on the pipeline that diverts the explosion to a safe area to prevent flame ejection ignition, pressure superposition, and reduce the probability of flame propagation to adjacent equipment.
3.8 Maximum Experimental Safe Gap; MESG
The maximum gap width that can prevent the flame of a dust explosion from propagating from the interior of the enclosure to the exterior.
4 Technical Requirements
4.1 Basic Requirements
4.1.1 Before adopting explosion isolation measures, the risk of dust explosion propagation in the process system should be identified and assessed. According to the process safety requirements, a suitable explosion isolation system should be selected.
4.1.2 The manufacturer of the explosion isolation system should provide product safety performance and usage instructions, and be responsible for the functional integrity of the product.
4.1.3 The enterprise should establish systems for the installation, use, maintenance, and maintenance of the explosion isolation system, and carry out periodic maintenance, maintenance, regular testing, or inspection of the explosion isolation system to ensure normal operation and keep relevant records.
4.1.4 The explosion isolation system should be able to prevent the propagation of the flame in the pipeline, between equipment, and between equipment and the workshop after the explosion occurs.
4.1.5 The manufacturer of the explosion isolation system should clearly state the design principle of the explosion isolation system, that is, to prevent the propagation of the flame and explosion shock wave or only to prevent the propagation of the flame.
4.1.6 The explosion isolation system should be used in combination with one or more explosion protection measures such as anti - explosion, explosion suppression, and explosion venting, and should not be used alone.
4.1.7 When the active explosion isolation system is used in combination with the explosion suppression system, the monitoring equipment of the two should be interlocked to trigger.
4.1.8 The explosion isolation device and the pipeline and container it protects should be able to withstand the maximum pressure and highest temperature that may occur, and ensure the integrity of the explosion isolation system.
4.2 Design and Selection
4.2.1 When selecting the explosion isolation system, it should be confirmed whether the applicable dust type, pipe diameter, and wind speed range of the explosion isolation system are suitable for the protected process.
4.2.2 Before designing explosion isolation measures, the basic information of the protected process and materials should be obtained, including but not limited to the following information.
a) Process information:
Process flow diagram;
Gas flow direction, wind speed, and pipe diameter in the pipeline;
Explosion protection measures already taken by the connected equipment;
Maximum controlled explosion pressure of the connected equipment.
b) Material information:
Type of dust;
Explosion grade;
Minimum ignition energy of the dust cloud;
Lowest ignition temperature of the dust cloud;
