Fire hazard classification of polyethylene and polypropylene

Both polyethylene and polypropylene belong to flammable materials, and both belong to serious danger level in fire hazard level.

1. polyethylene: polyethylene is flammable, and its oxygen index is 17.4. When burning, there is low smoke, a small amount of molten drops, and the flame is yellow-blue, with paraffin smell. Polyethylene is prone to photooxidation, thermal oxidation and ozone decomposition, and is easily degraded under the action of ultraviolet rays. Carbon black has a good shading effect on polyethylene. After irradiation, crosslinking, chain breakage and the formation of unsaturated groups will occur.

2. Polypropylene: easy to burn, and the product is easy to be aged by light, heat and oxygen in use. Non-toxic, tasteless, low density, strength, stiffness, hardness and heat resistance are superior to those of low-pressure polyethylene, and it can be used at about 100℃.

Good dielectric properties, high-frequency insulation, not affected by humidity, but brittle at low temperature, not wear-resistant, easy to age. Suitable for manufacturing general mechanical parts, corrosion-resistant parts and insulating parts. Common organic solvents such as acid and alkali have little effect on it and can be used for tableware.

Extended data:

Fire hazard level:

1, light hazard level: hotels and office buildings with a building height of 24m or less. Only the buildings in the closed system are set in the walkways.

2. Medium risk level: high-rise civil buildings: hotels, office buildings, comprehensive buildings, postal buildings, financial and telecommunications buildings, command and dispatch buildings, radio and television buildings (towers), etc.

(1) public buildings (including single-storey and multi-storey buildings): hospitals, sanatoriums, libraries (except stacks), archives, exhibition halls (halls), theaters, concert halls, auditoriums (except stages) and other entertainment places, railway stations, airports, docks, shopping malls with a total construction area of less than 5,000 ㎡ and a total construction area of less than 6,000 ㎡.

(2) Cultural heritage buildings: ancient wooden buildings and national cultural relics protection units.

(3) Industrial buildings: building components such as preparation workshops, cold storage and steel roof trusses in food, household appliances and glass products factories.

(4) Civil buildings: stacks, stages (except grape racks), parking lots and shopping malls with a total construction area of 5,000 ㎡, and underground shopping malls with a total construction area of 1 1,000 ㎡.

(5) Industrial buildings: material preparation and production workshops of cotton, wool, hemp, chemical fiber textiles, fabrics and products, wood, wood and plywood, grain processing, tobacco and products, drinking wine (except beer), leather and products, paper and paper products, pharmaceuticals and other factories.

3. Serious danger level: the material preparation workshops of printing plants, alcoholic products, flammable liquid products and other factories. Flammable liquid spraying operation area, solid flammable materials, flammable aerosol products, solvents, paints, asphalt products and other factory materials and the lower part of the production workshop, studio and stage "grape trellis".

4. Warehouse risk level: food, tobacco and alcohol, incombustible articles packed in wooden cases and cartons, shelf areas of warehouse-type shopping malls, etc.

(1) Wood, paper, leather, grain and its products, cotton, wool, hemp, chemical fiber and its products, household appliances, cables, Class B plastics and rubber and its products, steel-plastic mixed materials products, all kinds of incombustible articles packed in plastic bottles and warehouses where all kinds of articles are mixed.

(2) Group A plastics and rubber and their products, asphalt products, etc.

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