General: Fire Safety Technology (II) Building Fire Inspection

Chapter One   General layout and layout inspection

The first section   Building classification and fire rating

First, building classification

There are many ways of building classification, according to the building fire protection design code: industrial buildings include single-storey, multi-storey and high-rise factory buildings and warehouses, of which, fire hazard categories are divided into A, B, C, D, E; civil buildings Including single-storey, multi-storey and high-rise residential buildings and public buildings, among them, the categories of high-rise civil buildings are divided into one type and two types. In the fire inspection, the inspection of the height, number of layers, fire risk, and the nature of use of the building is mainly conducted to verify whether the building classification (including fire hazard classification for industrial buildings) complies with the requirements of the current national engineering construction fire protection technical standards.

(a) check the contents

1 . building height

The building height is the basis for defining whether a building is a high-rise building . Residential buildings with a building height of more than 27m and other non-single- store buildings with a building height of more than 24m are high-rise buildings. When checking the building height, you need to pay attention:

( 3 ) When the same building has multiple types of roofing, the building height is calculated according to the above method and the maximum value is taken.

( 4 ) For stepped floors, there are firewall partitions between the same buildings on different heights and floors, each with safety exits that comply with the regulations, and through-the-fire or end-fires along the two long sides of the building. In the lane, the respective building heights can be determined separately. Otherwise, the height of the building is determined by the height of the building.

( 5 ) When the roof area of ​​the observation tower, cooling tower, water tank room, microwave antenna room or facility, elevator machine room, ventilation and smoke extraction room and staircase exit room, etc., occupy a roof area of ​​not more than 1/4 , It does not need to be included in the building height.

( 6 ) For residential buildings, set at the bottom and indoor height is not more than 2.2m The height of the bicycle storage, storage room, open space, indoor and outdoor height difference or the top or bottom basement of the building above the height of the outdoor design floor is not more than 1.5m The portion is not included in the building height.

2 . Building layers

The number of building layers is determined by the number of natural layers of the building. When checking the number of building layers, you need to pay attention:

( 1 ) The height of the top floor of the basement and semi-basement of a building is less than or equal to 1.5m above the height of the outdoor design floor, and the bicycle storage, storage room, open space with a height of no more than 2.2m is set at the bottom of the building, and the roof of the building protrudes. Local equipment rooms, stairwells out of the house, etc. are not included in the number of building floors.

( 2 ) When a residential building or a residential building provided with other functional space has a floor height of more than 3m in one or several floors , these floors are first converted by their total height divided by 3m , and the remainder is less than 1.5m . , more than part of the building is not included in the number of floors; when the remainder is greater than or equal to 1.5m , more than part of the building layer counted by 1 floor.

3. Fire risk of production

When checking the fire risk category of a factory, you need to pay attention to:

( 1 ) When there is a risk of fire in any of the fire prevention zones within the same factory building or plant, the production fire hazard category within the plant or fire zone shall be determined based on the portion of the fire hazard that is greater; when used or produced in the production process If the amount of flammable and flammable substances is small enough to constitute an explosion or fire hazard, it shall be determined according to the actual situation. For example, a mechanical repair shop or repair shop, although using a small amount of gasoline and other Class A solvents to clean parts, but because of its small number, when all the gas escapes or the gasification of combustible liquids will not make any part of the plant at the same time The gas mixture is within the explosion limit. Therefore, the fire risk of the plant can still be considered in the category of E.

( 2 ) The proportion of the production area where the fire hazard is relatively high is less than 5% of the area of ​​this floor or this fireproof partition, or the paintwork area within the D, E-type factory building is less than 10% , and the fire accident is not sufficient to spread to other sites or If the part of the fire that has a high risk of fire has taken effective fire protection measures, it shall be determined according to the part where the fire risk is low.

( 3 ) For the paintworks in the D and E buildings, when the closed spray painting process is used, negative pressure shall be maintained in the closed spray paint space, and a flammable gas detection alarm system or automatic explosion suppression system shall be installed in the paintwork section, and the paintwork section shall occupy the fireproof partition area where it is located. When the proportion is not more than 20% , it is determined according to the less dangerous part of the fire. For example, in a car assembly plant, the spray painting workshop accounts for less than 20% of the area of ​​the assembly plant , and when the paint spraying section is protected by fire separation and automatic fire extinguishing facilities, the production fire risk category of the factory can still be classified by category E.

4. Fire risk of stored items

When checking the warehouse fire hazard category, you need to pay attention to:

( 1 ) When storing fire hazards in any of the fire compartments of the same warehouse or warehouse, the fire risk of the warehouse or fire compartment is determined by the item with the highest fire risk. For example, if the same warehouse stores items A, B, and C, the warehouse will need to be classified according to the A storage warehouse.

( 2 ) D and E materials are difficult to burn or burn, but there are many items that are flammable wooden boxes, cartons, foam plastics, etc. When the weight of flammable packaging is greater than 1/4 of the weight of the article itself or the volume of flammable packaging (such as foam, etc.) is greater than 1/2 of the volume of the article itself , class C shall be used to determine the fire hazard of the warehouse.

5. Civil Building Category

When checking civil building categories, you need to pay attention to:

( 1 ) Non-residential residential buildings such as dormitories and apartments are classified according to the relevant requirements of public buildings.

( 2 ) In the actual building fire inspection, the situation is more complicated. It is necessary to determine whether there are many buildings, high-rise buildings or single-storey buildings according to the number of floors and the building height of the main functional parts of the building. When it is difficult to distinguish the main function of a building and the single-layer part is not separated from the multi-layer or high-level part by a firewall, the building is determined as a multi-storey or high-rise building.

( 3 ) In the actual building fire inspection, if there are any buildings that are not listed in the specification, the building category must be determined by analogy based on the specific conditions of the building function. For example, in a high-rise medical building, taking into account the fact that many people in the building are inconvenient for mobility and difficult to evacuate, a fire in the building is prone to causing casualties. Therefore, it is divided into a group of high-rise buildings.

(b) Inspection methods

Through on-line inspection of fire control design documents, building plans, section drawings, and other relevant data to understand the fire protection design identified building layers, building heights, fire hazards and other basic data to determine the type of building after the on-site inspection. Check the floor number of the building, measure the height of the building, check the function and layout of each floor, the nature and quantity of the substances used or produced in the production, or the nature of the stored goods and the quantity of combustibles, etc., and check the accuracy of the building classification.

Second, the building fire rating

(a) check the contents

1. Burning performance and fire resistance of building components

The combustion performance and fire resistance of the main components of the building shall not be lower than the requirements of the corresponding fire rating of the building. The main inspection requirements: The main components of Class 1 fire-resistant building are non-combustion bodies; the main building components of Grade II fire-resistance, except that the ceiling is difficult to burn, the rest of the components are non-burning bodies; And the partition wall is difficult to burn outside the body, the rest of the components are non-burning body; four fire-rated building components, in addition to the rest of the firewall outside the body can be used to burn or burn body. The fire resistance rating of a building with wooden pillars and non-combustible materials as a wall is determined in four stages.

2 . Consistency of fire rating and building classification

The required fire rating is different and the inspection requirements are:

( 1 ) Factory and warehouse

1 When using or storing equipment or items such as special valuable machines, instruments, instruments, etc., the fire resistance rating of the building shall not be lower than one class.

2 High-rise factory buildings, Class A and B plants, workshops that use or produce Class C liquids, and D plants with sparks, red hot surfaces, and open flames, oil-immersed transformer rooms, high-voltage distribution equipment rooms, boiler rooms, elevated warehouses, and high-rise buildings. Warehouses, Class A warehouses, and multi-storey Class B warehouses, grain silos, and buildings are rated not less than Class II.

3 single and multi-layer C type workshops, multi-layer D and E type workshops, single-layer B type warehouses, single and multi-layer C type warehouses and multi-layer D and E type warehouses, and grain warehouses, and the fire resistance rating of the buildings shall not be lower than Three levels.

4 Independent Class A and B single-storey factory buildings with a building area of ​​not more than 300 m2 , single-storey C-type factory buildings with a building area of ​​not more than 500m2 , or single-layer D-plants with a building area of ​​not more than 1,000m2 , and total evaporation of coal-fired boiler rooms and boilers. When not more than 4 t/h , three-grade fire-resistant buildings can be used.

( 2 ) Civil Buildings

The fire resistance rating of underground or semi-underground buildings (Rooms) and one type of high-rise buildings shall be no less than one level; the fire resistance rating of single, multi-storey important public buildings and Class II high-rise buildings shall be no less than Grade II. Important public buildings here refer mainly to Public buildings that have a great influence on the political, economic and productive activities of a certain area and the normal life of residents, such as telecommunications, medical care, and power dispatching.

( 3 ) Car garage, repair garage

The fire resistance rating of the garages, repair garages, and Class I garages and garages of underground, semi-underground and high-level garages, and A and B category goods transport vehicles shall be no less than one class. The fire resistance rating of Class II and III garages and garages shall not be lower than Class II. The fire resistance rating of Class IV garages and garages shall not be lower than Class III.

3. Consistency of fire resistance rating and number of building layers

Buildings with different fire resistance levels may have different building layers. The inspection requirements are:

( a ) factory building

The Class B factory building with Class II fire resistance can have a maximum of 6 floors; Class 3 Class III fire-resistant buildings can have a maximum of 2 floors, and the D and E buildings can have a maximum of 3 floors.

( 2 ) Civil buildings with special facilities such as children's houses, children's activity venues, and activities for the elderly

1 When a children's play area such as a nursery or kindergarten, an activity site for the elderly, or a children's play hall is set in a Class I or Class II fire-resistant building, the floor of the place must not exceed 3 stories.

2 Children's houses in shops, nurseries, and kindergartens, children's activity places such as elderly activity sites and children's play halls, hospitalizations in hospitals and nursing homes, teaching buildings, canteens, food markets, theaters, cinemas, and auditoriums, when set at the third level In fire-resistant construction, the site should not exceed 2 floors.

3 Children's houses in shops, nurseries, and kindergartens, children's activity places for elderly people's activities and children's playrooms, hospitalizations in hospitals and nursing homes, teaching buildings, cafeterias, vegetable markets, when installed in four-grade fire-resistant buildings, Places are only allowed on the ground floor.

(b) Inspection methods

Conduct on-the-spot inspections to view the structural forms of buildings, types of various basic building components, comparison of firefighting design documents and construction and supervision records, and item-by-item measures of the cross-sectional dimensions of construction components, the thickness of protective layers, and the fire protection of metal components. Conduct measurements, analysis and judgment to verify whether the fire resistance rating of the building complies with the current national fire safety technical standards. Among them, when inspecting fire protection coatings for steel structures, the following operations are mainly performed:

1. Compare samples. Indoor exposed steel structures, steel structures with light roofs and steel structures with decorative requirements, when the fire-resistance limit is specified at 1.5 h and below, thin-coated steel structure fire-retardant coatings are preferred . For indoor concealed steel structures, high-rise all-steel structures and multi-storey factory steel structures, when the fire-resistance limit is specified to be more than 1.5 h, the fire-retardant coating for steel structures shall be thick-coated. For open-air steel structures, steel fireproof coatings suitable for outdoor use are selected.

2. Check the coating base. Check the construction inspection records. The surface rust and anti-corrosion paint of the steel surface prior to the application of the fire retardant coating meets the design requirements and the relevant national standards. The base layer of the fire retardant coating is free of oil, dirt, dirt, and dirt.

4. Check the coating thickness. The thickness of the coating is measured with a stylus (thickness meter). The coating thickness of the thin-coat fire-retardant coating meets the design requirements for fire resistance; the coating thickness of the thick-coat fire-retardant coating, 80% or more, meets the fire endurance limit. Design requirements, and the thinnest thickness is not less than 85% of the design requirements .

5. Check the surface cracks. The surface crack width of the thin coating type fireproof coating is not more than 0.5mm ; the surface crack width of the thick coating type fireproof coating is not more than 1mm .

  Chapter two   General layout

First, the overall layout of the city's fire safety

7. The dedicated terminals and stations for the shipment of liquefied petroleum gas and other flammable and explosive chemicals are located in independent safety zones in cities or port areas. The distance between a dedicated terminal for the shipment of liquefied petroleum gas and other flammable and explosive chemicals and the distance between the terminal and other goods shall not be less than twice the length of the largest ship, and the distance from the main navigation channel shall not be less than twice the length of the largest ship.

8. The layout of urban fire stations is rationally combined with urban traffic conditions and fire hazards in each area; street layout and layout of municipal fire hydrants can meet the needs of fire fighting and rescue; the distance between street center lines is generally within 160m , and the municipal fire hydrant is The layout of roads that can pass through fire engines shall not exceed 120m .

It should be noted that for enterprises in the old urban areas that seriously affect urban fire safety, they must be promptly included in the renovation plan and take measures to relocate or change the nature of production use within a limited period of time. For the construction-intensive areas and shanty towns with low fire-resistance grades, we must combine the renovation project with the removal of some old houses to build first- and second-grade fire-resistant buildings; for those that cannot be dismantled and rebuilt, the fire-resisting area with a floor area of ​​not more than 2500 can be divided . Partitions, set aside no less than 6m of fire protection between partitions or set up a firewall not less than 50cm above the building roof . For areas where there are no municipal fire hydrants or firefighting water shortages or firefighting vehicles, the water supply pipe diameters and fire hydrants must be added in conjunction with the reconstruction of the water supply pipes in the area, or firefighting cisterns with a capacity of 100m3 to 200 m3 should be constructed according to specific conditions. .

Second, the layout of common corporate general plane

Common enterprises mainly check the following contents in terms of general layout:

(I) Petrochemical Enterprises

1. Regional planning of the company

According to the production process of the plant and the production characteristics and fire risk of each component, and combined with terrain, wind direction and other conditions, check the general layout of the company's functional zoning, centralized layout of buildings and devices. Facilities, tanks, loading and unloading areas, or plant-wide sewage treatment plants that may emit flammable gases, and may be placed on the upwind side of the annual minimum frequency wind direction in places of personnel concentration, open flames or sparks; in mountainous or hilly areas , need to avoid being placed in the nest zone.

2. The main entrance

There are not less than two major entrances and exits in the factory, set in different directions. The roads in the production area should adopt two lanes. The process equipment area, the liquefied hydrocarbon storage tank area, the flammable liquid storage tank area, the loading and unloading area, and the chemical dangerous goods warehouse area are provided with circular fire lanes as required.

3. Corporate fire station

The location of the fire station is convenient for the fire truck to quickly reach the process plant area and the tank area, and it should be located on the downwind side of the production area with the minimum frequency wind direction throughout the year and avoid the main pedestrian flow path of the plant.

(b) Thermal Power Plant

1. Site selection

The site is located on the low-lying edge of the plant area. When security facilities are provided, they can also be placed on the high-margin frontier. In the ignition tank area located in the plant area, the height of the fence is not to be less than 1.5m ; when the fence of the plant area is used as the fence of the ignition tank area, the height of the physical fence is not less than 2.5m .

2. The main entrance

There are no less than two entrances and exits in the factory, and its location is convenient for fire trucks to enter and exit. A circular fire lane is set around the main plant, ignition tank area and coal storage yard.

Third, the fire spacing

The fire prevention distance is the distance between fire prevention buildings that prevents the ignition of adjacent buildings within a certain period of time and facilitates fire fighting. In the fire inspection, the on-site inspections are carried out after consulting the fire design instructions, master plans, and other information to understand the fire separation distances that the building category needs to meet. The inspection contents mainly include the fire separation between buildings of different types of buildings, between the two wings of a U -shaped or mountain-type building, and between groups of buildings; for refueling and filling stations, petrochemical enterprises, oil and gas projects, oil depots, etc. In the construction project, it is necessary to simultaneously check the fire prevention distance between the construction project and the surrounding residential areas, neighboring factories and mines, facilities, and internal constructions, structures, and facilities of the construction project.

(a) Measurement of fire separation

The requirements for the setting of common building fire prevention spacing can be found in the relevant contents in Chapter 4 of the second chapter of "Fire Safety Technical Practice". When measuring the fire separation distance, choose a relatively close measurement interval along the perimeter of the building. The allowable negative deviation of the measured value shall not exceed 5% of the specified value . Specific measurement method:

( II ) Treatment when the fire separation distance is insufficient

When the fireproof spacing is insufficient, it is necessary to check whether the building adopts the reinforced measures that meet the requirements of the current national engineering construction firefighting technology standards. The specific contents of Chapter 4 of the second chapter of “Fire Safety Technical Practice” can be seen. If you cannot meet the requirements due to various reasons such as the venue, you can take some corresponding measures according to the specific circumstances:

1. Change the nature of production or use within the building to minimize the fire risk of the building; change the fire resistance of the structure of the house and improve the fire resistance rating of the building.

2. Adjust the part of the process flow in the production plant and the quantity of stored goods in the warehouse; adjust the fire resistance and combustion performance of some components.

3. Change the normal exterior wall of the building to a firewall.

4. Remove old obsolete buildings that have low fire resistance, small floor space, and poor applicability and are adjacent to new buildings.

5. Set up an independent firewall and so on.

Fourth, the fire lane

(a) check the contents

1. Fire lane form

Common forms of fire lanes include circular fire lanes, end-type fire lanes, fire lanes that run through buildings, and intermediate fire lanes that connect to circular fire lanes. For different types of buildings, open storage yards and storage tanks, the specific inspection requirements are:

( 1 ) Factory and warehouse. Fire lanes are set in factories and warehouses. When the plant level, greater than the area of 3000m2 A, B, and Class C plant area greater than 1500m2 of B, Class C warehouse fire provided in the form of an annular channel, it is really difficult, along the length of the building can be two Set fire lanes.

( 2 ) Civil construction. High-rise civil buildings, stadiums with more than 3,000 seats, auditoriums with more than 2,000 seats, exhibition halls with an area of ​​more than 3,000 square meters , single-storey and multi-storey public buildings, and fire-fighting lanes in the form of a ring. When there are difficulties, they can be along the building. The two long sides set the fire lane. For residential buildings and high-rise buildings built on hillsides or riversides, fire lanes can be located along one long side of the building, but the facade of the building where the long side is located is the fire truck climbing operation surface.

( 3 ) Buildings along the street and buildings with closed inner courtyards or patios. For buildings with a length of more than 150m along the street or a total length of more than 220m , a fire lane is set through the building. When there are difficulties, an annular fire lane can be set along the perimeter of the building. For buildings with an inner courtyard or patio with a short side length greater than 24m , a fire lane into the inner courtyard or patio should be provided. No facilities affecting the passage of fire trucks or the safe evacuation of personnel shall be allowed on either side of the fire lane that passes through the building or into the courtyard of the building.

( 4 ) Car garage, repair garage. The garage, garage, and fire lanes are all set in a ring shape. When there are difficulties, fire lanes can be set along the two long sides of the building. Fire lanes can also use traffic lanes.

( 5 ) Open storage area and storage tank area. Combustible materials open storage area, liquefied petroleum gas storage tank area, A, B, C liquid storage tank area and combustible gas storage tank area, set fire lanes. For the flammable material yard with an area of ​​more than 30,000m2 , the LPG storage tank area, the liquid storage tank area of ​​Class A, B, and C, and the combustible gas storage tank area, an intermediate fire lane that communicates with the circular fire lane is set.

2. Fire lane setting

The main inspection fire lane's net width and clearance height are not less than 4.0m , and its slope should not be greater than 8% ; its turning point meets the requirements of the turning radius of the fire truck, that is, the front-wheel outer-circumferential curve of the fire truck when the fire engine is turning. The radius of the general light series of fire engines is greater than or equal to 7m , the middle series of fire engines is greater than or equal to 9m , and the heavy series is greater than or equal to 12m ;

3. Fire lane return yard

The return lane or return yard set at the end of the fire lane, the area of ​​the return yard is not less than 12.0m × 12.0m , and the return yard area of ​​the high-rise civil building is not less than 15.0m × 15.0m for use by large-scale fire engines. Not less than 18.0m × 18.0m .

4. Fire lane bearing capacity

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