Fire prevention of steel structure

According to the Code for Fire Protection Design of High-rise Civil Buildings, when the fire protection level is Grade I, the fire resistance time requirements of members are: column: 3 hours, beam: 2 hours, floor: 1.5 hours; When the fire protection level is Grade II, the fire resistance time requirements of members are: column: 2.5 hours, beam: 1.5 hours, floor: 1 hour. Fire retardant coatings, thin fire retardant coatings should not exceed 1.5 hours, and thick fire retardant coatings should be used if it exceeds 1.5 hours.

Fire protection of steel members can be achieved by wrapping concrete (or building bricks), fire-retardant coating, fire-retardant board wrapping, composite structure and other methods. Fire boards can be divided into thick fire boards and thin fire boards with a thickness of 20 ~ 50 mm, mainly including calcium silicate fire boards and expanded stone fire boards, and the main varieties are KB boards and CF boards. The thickness of fireproof board is 6 ~ 15 mm, and the main varieties are short fiber reinforced cement pressure board, fiber reinforced ordinary calcium silicate board and glass cloth reinforced inorganic board.

As we all know, steel structures usually lose their bearing capacity in the temperature range of 450℃ ~ 650℃ and undergo great deformation, which leads to the bending of steel columns and beams. As a result, due to excessive deformation, they can no longer be used. Generally, the fire resistance limit of unprotected steel structures is about 15 minutes.

Therefore, when the fire protection grade of steel structure is Grade II, the fire resistance time requirements of members are: column: 2.5 hours, beam: 1.5 hours, floor: 1 hour. The steel structure can be wrapped with concrete (or brick), fire retardant coating, fire retardant coating and composite structure to reach the required fire resistance limit time.

The above content comes from China Refractory Brick Trading Network.