In simple terms, the extent of fire-retardant materials divided into four categories:
1.A grade, non-burning materials.
2.B1 level, difficult to burn materials.
3.B2 grade, combustible materials.
4.B3 level, flammable materials.
Achieve the following requirements of the material, its combustion performance as B1 level.
 
a) according to GB / T 8626 test, the combustion performance indicators should meet GB / T 8626 and is not permitted under the drip burning paper ignited the phenomenon;
b) according to GB / T 8625 test, the average remaining length ≥375px each set of specimens (including any remaining length of a specimen of> 0), and each test average flue gas temperature peaks ≤200 ℃.
c) according to GB / T 8627 to test their smoke density rating (SDR) ≤75.
 
This criterion is burning material grades were strictly divided, its flame retardant B1 level standard has three major indicators:
(1) Oxygen Index: ≥32.0%;
(2) vertical combustion performance: burning time ≤30S, burning highly ≤250mm;
(3) smoke density rating: ≤75SDR
Interior decoration materials, the fire protection requirements, the total level on points A, B1 level, B2 level! In terms of fire safety requirements, the top surface decorative material must be Class A fire, wall, floor decoration materials must be B1 level fire! For example, you say light steel keel plasterboard, tiles, metal blinds, etc. is a Class A fire retardant carpet and the best can only belong to B1 level fire!