Fire resistance rating: “Non-combustible 1.5h””

That time period is known as the fire resistance limit. Article 2.1.10 of the revised Code for Fire Protection Design provides a specific definition: under standard fire testing conditions, it is the time, expressed in hours, that passes from the moment a building component, fitting, or structure is exposed to fire until it loses its stability, integrity, or thermal insulation properties. Flame resistance refers to all the physical and chemical changes that occur when building materials burn or are exposed to fire. This property is determined by characteristics such as the ignition behavior and flame spread of the material’s surface, heat generation, smoke production, carbonization, weight loss, and the formation of toxic substances. Classification of combustion ratings: China’s standard GB8624-97 classifies the combustion performance of building materials into the following categories. Grade A: Non-flammable building materials; Grade B1: Slightly flammable building materials; Grade B2: Flammable building materials; Grade B3: Highly flammable building materials. The new national standard \"Classification of Combustibility of Building Materials and Products\" (GB8624-2006) came into effect on March 1, 2007, and it classifies the combustibility of building materials and products into seven grades: A1, A2, B, C, D, E, and F. To ensure a smooth transition between the old and new standards, Document No. 182 issued by the Ministry of Public Security outlines the classification of combustion performance standards under both systems: New Standard grades A1 and A2 correspond to Old Standard grade A, New Standard grades B and C correspond to Old Standard grade B1, and New Standard grades D and E correspond to Old Standard grade B2.

Indeed, there are indeed differences between the old and new standards!