In-depth analysis of lsoh cables What are the differences between the civilian standard GB/T and the military standard GJB?

While both civilian low-smoke halogen-free cable standards (such as the GB/T series) and military low-smoke halogen-free cable standards (GJB national military standards) focus on the three core characteristics of “low smoke, halogen-free, and flame retardant,” they differ significantly in terms of application scope, performance requirements, testing rigor, environmental adaptability, and certification systems. TST CABLE Nico will guide you through a comparison of these two standards :

I. Different Standards and Applicable Objects

✅ Key difference: GJB is a mandatory entry threshold for military industry, while GB/T is mostly recommended and is only cited as a mandatory requirement in fire protection acceptance or specific projects.

II. Comparison of Core Performance Indicators

1. Low smoke density

GB/T / GB 31247:

Minimum transmittance required: ≥ 60% (corresponding to S1 grade).

GJB (e.g., GJB 773A):

The same requirement applies to light transmittance ≥ 60%, but the testing conditions are more stringent (such as higher flame temperature and longer burning time), and the test must still meet the standard after salt spray and damp heat pretreatment.

2. Halogen-free

GB/T:

The release of halogen acid gas is ≤ 5 mg/g (according to IEC 60754-1 or GB/T 17650).

GJB:

While maintaining the same level of ≤ 5 mg/g, we added dual control of the corrosive gas pH value and conductivity (e.g., pH ≥ 4.3, conductivity ≤ 10 μS/mm) to ensure no corrosion to precision electronic equipment.

3. Flame Retardancy

GB/T:

It is divided into four levels: A, B, C, and D. Level B1 requires passing the bundle combustion test (IEC 60332-3 Category C).

GJB:

Not only is compliance with IEC 60332-3 required, but also vertical combustion self-extinguishing time ≤ 5 seconds and flame spread distance shorter (e.g. ≤ 1.5 meters vs. 2.5 meters for civil use).

III. Environmental adaptability requirements (GJB standards far exceed those for civilian use)

This is the most crucial difference. Military cables must operate reliably in extreme environments:

�� For example: A GJB low-smoke halogen-free cable used in the J-20 fighter jet needs to not crack when starting at -55°C, operate for a long time at a high temperature of 125°C in the engine compartment, and withstand the violent vibrations during takeoff—these are things that civilian cables do not need to consider at all.

IV. Differences in Materials and Structures

V. Certification and Quality Control

Civilian use:

Products can be marketed once they pass CCC certification (mandatory from July 2025) and have a test report.

The main method is random sampling, and the requirements for batch consistency are relatively lenient.

military:

Military industry certification qualifications must be obtained (such as national military standard certification, equipment manufacturing qualification).

Implement full batch inspection + sample retention for traceability;

The production process must comply with the GJB 9001C quality management system.

Suppliers must pass a rigorous on-site audit.

In short, distinguish them in one sentence .

Civilian low-smoke halogen-free cables = safe and environmentally friendly + fire protection compliant;
Military low-smoke halogen-free cables = extremely reliable + battlefield survivability + zero failure tolerance.

Although both are called “low-smoke halogen-free,” military products far surpass civilian-grade products in reliability, environmental adaptability, lifespan, and consistency, and their cost is often 3–10 times that of civilian products. Ordinary engineering projects do not require the use of military cables, while military projects strictly prohibit the use of civilian products that only meet GB/T standards.

✅ Tip: In “quasi-military” fields such as rail transit, nuclear power, and aerospace, enterprise or industry standards are often formulated with reference to some requirements of GJB to form “high-end civilian” solutions. This is also an important market direction for TST CABLE ‘s high-end LSZH cables.

TST CABLE is one of the few high-tech enterprises in China with the full R&D and manufacturing capabilities for both civilian and military low-smoke halogen-free cables. Its products comprehensively cover civilian standards such as GB/T 19666 and GB 31247, as well as national military specifications such as GJB 773A and GJB 1916, and are widely used in nuclear power, hydropower, wind power, rail transportation, data centers, and defense equipment such as ships and aviation. TST CABLE possesses independent high-performance halogen-free flame-retardant material formulations, irradiation cross-linking production lines, and military-grade testing laboratories. It has passed CCC certification, national military standard certification, and equipment manufacturing qualifications, achieving full-chain independent control from materials to finished products, and its technological strength is industry-leading. With its superior sealing performance and stringent quality control, TST’s modular perforation sealing system has not only passed the EU Marine Equipment Directive (MED) certification, but has also obtained certifications from six major global classification societies: CCS, ABS, DNV, BV, RS, and RINA. This makes it one of the very few domestic companies to achieve this breakthrough, signifying that its products fully meet the highest international standards in terms of reliability, safety, and consistency. It has also successfully achieved domestic substitution in key areas such as ship decks, providing comprehensive perforation sealing protection for cables and pipes, and becoming a trusted safety barrier for shipyards and ship owners.

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