1. Fireproof grade an is a flame retardant material without ignition point and thermal insulation effect. At present, it mainly involves glass beads, closed hole expanded perlite, rock wool, mineral wool, glass wool, phenolic board, cement-based or gypsum based inorganic thermal insulation mortar and light self thermal insulation system.

2.耐火级B1是根据材料的耐火等级限度确定的耐火隔热材料。此外，不同部位的材料划分也不同!燃烧性能：指材料和(或)产品在燃烧时发生的所有物理和/或化学变化，即对火的反应特性。

2. Fire resistance grade B1 is a fire-resistant and thermal insulation material determined according to the fire resistance rating limit of the material. In addition, the material division of different parts is also different! Combustion performance: refers to all physical and / or chemical changes of materials and / or products during combustion, i.e. reaction characteristics to fire.

3.B2级是一种可燃保温材料，又称阻燃材料，主要是隔热材料，添加适量的阻燃剂。它们大多是EPS膨胀聚苯乙烯板和XPS挤塑聚苯乙烯板，我们通常称之为通用板。这种材料的燃点低，燃烧过程中释放大量有害气体。

3. Class B2 is a combustible thermal insulation material, also known as flame retardant material. It is mainly thermal insulation material, and an appropriate amount of flame retardant is added. Most of them are EPS expanded polystyrene board and XPS extruded polystyrene board, which we usually call general board. This material has a low ignition point and releases a large amount of harmful gases during combustion.

4.防火级B3武汉泡沫板是一种易燃保温材料，常用作聚苯乙烯泡沫塑料的主要材料，由于该材料易烧，目前已从外墙保温材料中淘汰。

4. fire grade B3 Wuhan foam board is a kind of flammable and thermal insulation material. It is commonly used as the main material of styrofoam, because it is easy to burn, it has been eliminated from external wall insulation materials.