How to remember the fire resistance rating and classification of buildings?

Fire resistance rating is divided into one, two, three and four levels:

The first grade is the highest, the fire resistance is the strongest, the fourth grade is the lowest and the fire resistance is the weakest. The so-called building components refer to a series of basic components such as walls, foundations, beams, columns, floors, stairs and ceilings.

1, the combustion performance of building components refers to the reaction of building component materials in case of fire, which is divided into three categories: incombustible, fire-resistant and combustible, and incombustible for building components, such as wall columns and foundations; Refractory objects, such as hangers, ceilings and internal pipes; Burners such as doors and windows, ceilings and decorative materials.

2. Fire resistance limit of building components: any building component is tested according to the time-temperature standard curve, and the time from the beginning of fire to the loss of supporting capacity or integrity or fire prevention function is called fire resistance limit, which is expressed as "h" in hours. Time-temperature standard curve refers to an idealized test curve showing the development of on-site fire under standard laboratory conditions according to a specific heating method. This curve was adopted by the International Organization for Standardization (ISO) in order to have a unified test standard for the ultimate fire resistance time of building components.