The Chinese fire classification system
China classifies building materials under GB 8624, which grades a product from A to B3:
- A (A1 and A2): non-combustible. Stone, steel, glass, mineral wool.
- B1: difficult to ignite, limited flame spread and limited heat release. This is the grade most interior acoustic panels are specified to.
- B2: combustible but acceptable in lower-risk locations with a lower occupant load.
- B3: easily combustible - not permitted as a building material.
The tests behind the grade are GB/T 5464 (non-combustibility), GB/T 8626 (ignitability), and GB/T 8627 (smoke density), read alongside heat release data.
B1 versus B2 in practice
B1 materials resist ignition, slow the spread of flame across the surface, and release a limited amount of heat. B2 materials are flammable but slow-burning enough to be tolerated in lower-risk positions. The practical consequence is where each is allowed.
Where B1 is normally required
- High-rise public buildings and their lobbies and lift areas.
- Underground spaces, including car parks and metro concourses.
- Cinemas, KTV rooms, theatres and other assembly occupancies.
- Corridors and evacuation routes in almost any public building.
- Hotel guest rooms and upper-floor commercial fit-outs.
Do not confuse GB 8624 B1 with ASTM E84 Class A
They are different tests with different scales and they are not interchangeable. ASTM E84 Class A describes flame spread and smoke developed in a Steiner tunnel test used in North America; EN 13501-1 uses a European scale running from A1 to F; GB 8624 is the Chinese system. Export projects need the standard the destination authority recognises - if you are shipping to the United States, you need Class A per ASTM E84, even if the factory holds a B1 report for domestic sales.
What to ask the factory for
- A test report issued by a CNAS-accredited laboratory, with a traceable report number and a date appropriate to the current formulation.
- Confirmation of which component was tested - the whole assembly, not just the surface film.
- The declared grade on the production label, matched to the report number.
- A retained sample from your production batch if the project has an inspection regime.
Which part of the panel burns?
Two components matter. The substrate - usually MDF for slat panels - is treated with flame retardant to achieve B1. The PET felt contains a flame-retardant additive; without it, polyester felt behaves like a B2 material. PVC wall panels rely on formulated compounds and fillers. When a supplier claims B1, ask which of these three was tested.
Fire safety on site
Material grade is only half the story. Fire stops must be maintained where panels cross a rated wall or ceiling, ceiling panels must be mechanically fixed as well as bonded, and panels should never be used to conceal a missing fire-stopping detail. Grade the material, then build it correctly.
Every OEM batch we ship can be supplied with the fire documentation your project requires. Tell us your destination market and we will confirm which certificate applies.