Building classification and fire resistance level?

Building classification is to determine the basis of fire safety requirements, mainly based on the use of the building function, fire danger, evacuation and fighting the difficulty of categorization, different categories of buildings to take different fire prevention measures to achieve both the protection of the building's fire safety, but also to save the investment purpose. The selection and determination of the building fire resistance level, is one of the most basic measures in the building fire safety technical measures, and the nature of the building use, the size of the fire danger, the design of the building of the number of floors, etc., closely linked to the building must be classified with the building to adapt.

I, building classification

There are many ways to classify buildings, according to the building fire code: industrial buildings, including single-story, multi-storey and high-rise factories and warehouses, of which the fire hazard category is divided into categories of A, B, C, D, E; civil buildings, including single-story, multi-storey and high-rise residential buildings and public **** building, of which, high-rise civil buildings are divided into one category and two categories. Fire inspection, mainly through the height of the building, the number of floors, fire danger, the nature of the use of the inspection, to verify that the classification of the building (industrial buildings including fire danger classification) is in line with the requirements of the current national engineering and construction fire technical standards.

(a) check the content

1. building height

Building height is to define whether the building is a high-rise basis, building height greater than 27m residential buildings and other buildings with a height greater than 24m non-single-storey building is a high-rise building. When checking the building height, it is necessary to note:

(1) When the building roof is a sloping roof, the building height is the average height from the outdoor design ground of the building to the gable end and the ridge of the roof.

(2) When the building roof is flat roof (including flat roof with daughter wall), the building height is the height from the outdoor design ground of the building to the roof surface.

(3) the same building has a variety of forms of roofing, building height according to the above method of calculation, take the maximum.

(4) for step floor, when located on different elevations of the floor of the same building is separated by a firewall, each has a safety exit in accordance with the provisions of the code, and can be set up along the two long sides of the building through or at the end of the type of fire truck lanes, you can determine the height of the respective building. Otherwise, the building height shall be determined according to the one with the largest building height.

(5) partially protruding from the roof of the watchtower, cooling towers, water tanks, microwave antenna rooms or facilities, elevator machine rooms, exhaust and smoke machine rooms and stairway exit cubicles and other auxiliary rooms accounted for the roof area of not more than 1/4, do not need to be included in the building height.

(6) For residential buildings, set at the bottom and the indoor height is not greater than 2.2m of the bicycle garage, storage room, open space, indoor and outdoor height difference or the building's underground or semi-basement of the top surface of the surface of the floor is not greater than 1.5m above the outdoor design of the ground level of the building is not included in the height.

2. The number of building floors

The number of building floors is determined by the natural number of floors of the building. When checking the number of building floors, it should be noted that:

(1) the building's basement, semi-basement roof surface height above the outdoor design of the ground is less than or equal to 1.5m, the height of the bottom of the building does not exceed 2.2m of the bicycle garage, storage room, open space, and building roof protruding from the local equipment room, out of the roof of the stairwells, etc., do not count as part of the building floors.

(2) When a residential building or a residential building with other functional spaces has 1 layer or several layers with a height of more than 3m, these layers shall first be converted into layers by dividing the sum of their heights by 3m, and when the remainder is less than 1.5m, the excess shall not be counted in the number of floors of the building; when the remainder is greater than or equal to 1.5m, the excess shall be counted in the number of floors of the building by 1 layer.

3. Production of fire hazards

The fire hazards of the plant is based on the production of the nature of the substances used or produced and the number of factors to determine the main categories of A, B, C, D, E and other five categories, the specific classification of the "fire safety technology practice" Chapter II, Chapter II of the relevant content. Plant fire hazard category inspection, need to pay attention to:

(1) the same plant or plant within any fire protection sub-area of different fire hazard production, plant or fire protection sub-area of the production of fire hazard category according to the fire hazard of the larger part of the determination; when the production process uses or produces a small amount of flammable, combustible material, not enough to constitute an explosion or fire hazard, according to the actual situation Determination. For example, machinery workshop or repair workshop, although a small amount of gasoline and other Class A solvents are used to clean the parts, but because of its small amount, when all the gas escapes or all the gasification of combustible liquids will not be in the same time, so that the gas mixture in any part of the plant is within the explosion limit. Therefore, the fire hazard of the plant can still be considered as Category E.

(2) the fire danger of the production part of the floor or the proportion of the area of the fire partition is less than 5% or D, E class plant painting section is less than 10%, and the occurrence of a fire accident is not enough to spread to other parts of the production part of the fire danger or fire danger of the production part of the effective fire prevention measures, according to the fire danger of the lesser part of the determination.

(3) D, E class plant paint section, when the closed paint process, closed paint space to maintain negative pressure, paint section set up combustible gas detection and alarm system or automatic explosion suppression system, and paint section of the area of the fire protection zone is not more than 20% of the proportion of the section, according to the fire hazard is smaller part of the determination. For example, in an automobile assembly plant, painting section accounts for less than 20% of the area of the assembly plant, and will be painted section of the use of fire separation and automatic fire extinguishing facilities to protect, the production of the plant fire hazard category can still be classified according to Category E.

4. Fire hazard of stored goods

The fire hazard of the warehouse is based on the nature of stored goods and the number of combustibles in the stored goods and other factors to determine the main categories of A, B, C, D, E and other five categories, the specific classification of the "Fire Safety Technical Practice" Chapter 2, Chapter II of the relevant content. Warehouse fire hazard category inspection, need to pay attention to:

(1) the same warehouse or warehouse of any fire protection sub-district storage of different fire hazardous items, the warehouse or fire protection sub-district of the fire hazard according to the fire hazard of the largest items to determine. For example, the same warehouse storage of A, B, C three categories of goods, the warehouse needs to be divided into A storage goods warehouse.

(2) D, E items itself is difficult to burn or non-combustible substances, but there are many items of packaging is combustible wooden boxes, cardboard boxes, Styrofoam and so on. Therefore, these two types of warehouses, in addition to considering the combustion properties of the items themselves, but also consider the number of combustible packaging, fire prevention requirements should be more stringent than the d, e warehouse. When the weight of combustible packaging is greater than the weight of the item itself 1/4 or combustible packaging (such as Styrofoam, etc.) volume is greater than 1/2 of the volume of the item itself, according to the C category to determine the fire hazard of the warehouse.

5. Civil building categories

Civil building categories are based on building height, functionality, fire danger and ease of fighting to determine the main residential buildings and public **** building two categories. For residential buildings, the building height of 27m to distinguish between multi-storey and high-rise residential, high-rise residential buildings and 54m to divide a class and the second class of high-rise residential buildings; for the public **** building, the building height of 24m to distinguish between multi-storey and high-rise public **** building, high-rise buildings and the nature of the important, fire danger, evacuation and rescue of buildings difficult to be divided into a class of high-rise public **** building. Specific categorization see "fire safety technical practice" Chapter 3 of the second chapter of the relevant content. Civil building category inspection, need to pay attention to:

(1) dormitories, apartments and other non-residential residential buildings, according to the relevant requirements of the public **** building to determine its category.

(2) For single-story public **** building with a building height of more than 24m, the situation is more complicated in the actual building fire inspection, which needs to be based on the number of floors of the main use function part of the building and the height of the building to determine whether it is a multi- or high-rise building or a single-story building. When it is difficult to distinguish between the main functions of the building, and the single-story part of the building and the multi-story or high-rise part of the building and do not use firewalls to separate, the building will be determined as a multi-story or high-rise building.

(3) in the actual building fire inspection, such as encountered in the specification is not listed in the building, the need for building function according to the specific circumstances, through the analogous division of standards to determine the building category. For example, high-rise medical buildings, taking into account the building there are a number of people with limited mobility, evacuation difficulties, fire in the building is prone to casualties, so it will be divided into a class of high-rise **** building.

6. Garage, garage, parking lot categories

Garage, garage, parking lot categories are based on the number of parking (spaces) and the total floor area to determine, mainly divided into Ⅰ, Ⅱ, Ⅲ, Ⅳ and other four categories. Specific categorization of the "fire safety technology practice," the fourth chapter of the eighth chapter of the relevant content.

(B) inspection method

By reviewing the fire design documents, building plans, sectional drawings and other relevant information, to understand the fire design to determine the number of floors of the building, building height, fire risk and other basic data to determine the building category to carry out on-site inspection. Field check the number of building floors, measure the building height, check the function and layout of each floor, the nature and quantity of substances used or produced in production or the nature of the stored goods and the number of combustibles, etc., to check the accuracy of the building classification.

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