The correct definition of flame retardant EPS foam material is actually a self-extinguishing material, that is, the material will be burned and melted quickly when exposed to open flames, but it will extinguish itself when it leaves the source of fire. Now, some of our users and related departments have an ambiguity in understanding the flame retardant EPS foam indicator standards and combustion performance. Based on this, we will provide references to the flame retardant EPS foam products' relevant indicator concepts and standard performance. .
First, several concepts involved in the application of flame retardant EPS foam
1. Oxygen index
The concept of oxygen index refers to the limit oxygen index, which is the maximum oxygen concentration obtained under specified test conditions. Generally, the higher the oxygen index, the better the flame retardancy of the material.
The limit oxygen index test method of flame retardant EPS is specified in GB / T10801.1-2002: the size of the sample is 150mm & # 215; 12.5mm & # 215; 12.5mm, the sample is aged for 28 days, and the oxygen index is not less than 30% ( The oxygen content in the air is 21%), so the concept of oxygen index must be related to two national standards: GB / T2406-93 (analysis method) and GB / T10801.1-2002 (determination basis).
2. Combustion classification
The concept originates from GB8624-1997 (Classification Method for Combustion Performance of Building Materials), and is divided into two major categories: non-combustible materials (grade A) and combustible materials (grade B). Class B is further divided into B1 / B2 / B3 according to the degree of flammability.
The B1 level is determined to meet three indicators at the same time: oxygen index ≥32 (GB / T2406); average burning time ≤30s, average burning height ≤250mm (GB / T8333); smoke density level (SDR) ≤75 (GB / T8627 ).
The B2 level is determined to meet two indicators at the same time: oxygen index ≥ 26 (GB / T2406); average burning time ≤ 90s, and average burning range ≤ 50mm (GB / T8332).
Second, conceptual misunderstanding
1. Intuitive test and flame retardancy
Press a corner from a freshly made or cut sheet and test it with a lighter. The surface flashes and the foam block melts. This phenomenon is that the sheet is too fresh, has not been treated in the oven and the storage period is too short, that is, it has not reached Aging requirements.
2.Insufficient oxygen index
Take a sample from the construction site and send it to the fire department for testing soon. It is said that the oxygen index is not enough to reach 30 after a few days, because the concept of oxygen index is not understood, and it should be in accordance with GB / T2406-93 Way to test (sample aging 28 days before testing).
3. Can B1 level be achieved?
So far, no national standards or regulations require EPS to reach B1 level. The actual test index of the oxygen index is closely related to the product density, the processing method of the plate, and the testing equipment