2017 Fire Safety Case Analysis Final Exam Paper Three (including answers)

Question 1 (20 points)

A nightclub has 3 floors above ground, with a building area of ??18mx60m=1080m2 on each floor, and a brick-concrete structure. The first floor is the lobby (190m2), disco (810m2) and fire control room (80m2), and the second and third floors are KTV private rooms (the construction area of ??each private room is not more than 200m2). The total building height is 12m. There is one outdoor above-ground fire hydrant 50m away from the gables on both sides of the nightclub. There are 3 DN65 fire hydrants on each floor of the building, using 25m fire hoses and 19mm fire water guns. The distance between the fire hydrants is 30m, and they are ring-shaped indoors. The fire water supply pipes are connected; the building is also equipped with a wet automatic sprinkler fire extinguishing system, using standard sprinkler heads. The distance between sprinklers should not be greater than 3.60m and the distance from the wall should not be greater than 1.80m. Indoor and outdoor fire water supply is taken from the municipal DN200 branch pipe network, and the water pressure is not less than 0.35MPa. The walkways on the 2nd to 3rd floors (width 2m, length 60m) and the disco on the first floor of the building do not have natural smoke exhaust conditions. They are equipped with a mechanical smoke exhaust system and a smoke exhaust machine room on the roof. The air volume of the smoke exhaust fan is 50000m3/h. . The disco is divided into two smoke-proof zones, with an area of ??410m2; emergency lighting and evacuation indicator lights are installed in each KTV room, disco room, walkway, stairwell, foyer and other places; fire hydrants on each floor are installed Set up two 5kg ABC dry powder fire extinguishers.

Based on the above scenario, answer the following questions.

1. What method should be used to connect the eccentric and large ends of the horizontal section of the water pump suction pipe and why?

2. How should fire water supply pipes be arranged when they pass through walls or floors?

3. What requirements should be met for the positional relationship between the air outlet of the smoke exhauster and the air inlet of the blower?

4. After the construction of the fire water supply pipe network is completed, pressure testing and flushing must be carried out. In what order should the flushing be carried out?

5. What is the spray intensity and area of ??effect of the wet automatic sprinkler system installed in this building?

Question 2 (20 points)

On the ground of a high-rise commercial complex** *10 floors, ***3 floors underground, the building height is 53.80m, and the total construction area is 67137.48m2. Among them, the underground part has a construction area of ??27922.30m2. It is used as a parking garage and equipment room. A total of 474 cars can be parked. The above-ground construction area is 39215.18m2. The usage of the 1st to 5th floors above ground is retail business. 6 above ground ~The 10th floor is used as a dining and leisure entertainment venue. The building is equipped with indoor and outdoor fire hydrant systems, automatic sprinkler systems, automatic fire alarm systems, fire emergency lighting, fire evacuation signs, fire extinguishers, fire elevators and other fire protection facilities; the fire control room is located on the first underground floor, and the fire pump room It is located on the 2nd floor underground. Electricity for fire protection is a primary load, and the power supply is introduced from two different regional substations; fire water supply is introduced from two DN300 water inlet pipes from the circular municipal water supply network, and a loop is formed within the plot.

Based on the above scenario, answer the following questions.

1. How should the number of outdoor fire hydrants in the building be determined?

2. Calculate technical parameters related to automatic sprinkler systems.

3. If the fire power supply is provided by a self-contained emergency generator set, what issues should be paid attention to?

4. What method should be used to prevent and exhaust smoke in this building?

5. How many fire elevators should be installed in this building? What requirements should the load capacity and driving speed of fire elevators meet?

Question 3 (20 points)

A garment factory, ***2 The floor height is 6m. The roof load-bearing components are flame-retardant components with a fire resistance limit of 0.5h. The columns are non-combustible components with a fire resistance limit of 2.5h. The building area of ??each floor is 4000m2, and each floor is divided into a fire protection zone. .

Directly to the north of the factory is a four-story aluminum powder factory with a fire-resistance rating of Level 2, with a floor height of 4.5m. To the south is a 3-story edible oil warehouse with a fire-resistance rating of Level 2, and to the west is a 2-story edible oil warehouse with a fire-resistance rating of Level 3. There is a 6-story printing and dyeing factory, and to the east is a 6-story packaging factory with a fire resistance level of Level 2. The garment factory has installed four smoke-proof stairwells that are not against the exterior walls and have a clear width of 1.10m for evacuation stairs. Except for the outer door on the first floor, which has a net width of 1.20m, the net width of other doors is 0.90m; the distance from any point in the factory to the nearest safety exit is not greater than 40m, and is configured in accordance with relevant national engineering construction fire protection technical standards. Fire-fighting facilities and equipment such as indoor and outdoor fire hydrant water supply systems and automatic sprinkler systems have been installed.

Based on the above scenario, answer the following questions.

1. Do the fire resistance levels and number of layers of the buildings and warehouses surrounding the garment factory meet the requirements? Why?

2. What is the fire resistance level of this garment factory? Is it appropriate to divide each floor into a fire protection zone?

3. If an office or rest room is set up in this garment factory, what requirements should be met?

4. What shape should the fire lane be installed in this garment factory? What requirements should the fire lane meet?

5. What requirements should be met for the fire protection distance between a garment factory and surrounding factories and warehouses?

6. If the clothing factory is subject to location constraints, the fire separation distance between the garment factory and the 4-story aluminum powder factory building with a 40-year-old fire resistance level of Class II is only 11m. Q: Under normal circumstances, the fire separation distance between the two should not be Less than how many meters? If the fire separation distance is insufficient, what measures can be taken to solve it and explain the reasons?

Question 4 (20 points)

A certain garage has a construction area of ??3999m2, underground* **1st floor, floor height 3.60m, the distance from the ground elevation of the underground garage to the outdoor ground shall not be greater than 10m. The garage can park 101 vehicles and is divided into 2 fire protection zones and 2 smoke protection zones. The garage is equipped with 2 evacuation exits for people and 2 evacuation exits for cars, and fireproof roller shutters are installed at the entrances and exits of the cars. The garage's fire power supply load is Level 2, and it is equipped with an automatic fire alarm system, automatic sprinkler system, indoor and outdoor fire hydrant water supply system, mechanical smoke exhaust system, emergency lighting and evacuation signs, smoke barrier and building fire extinguishers, etc. Fire protection facilities.

Based on the above scenario, answer the following questions.

1. What should the fire resistance level of this garage be?

2. What requirements should be met for the evacuation distance from any point in the garage to the nearest personnel safety exit? Can two adjacent fire protection zones in the garage use evacuation stairs, that is, two fire protection zones should be equipped with three stairs?

3. Briefly describe the method for determining the anti-fall performance of fire water guns.

4． What requirements should the garage emergency lighting and evacuation signs in the scenario description meet?

5. What installation requirements should the garage indoor fire hydrant system in the scenario description meet?

Question 5 (20 points)

In order to host the annual provincial college sports games, a university builds a new gymnasium. It consists of two parts: the main building and the auxiliary building. The main building is the competition hall and the auxiliary building is the training hall. The building height is 23m and the total construction area is 17,000m2. It adopts a frame and long-span steel roof truss structure system and has a fire resistance level of Level 2. The competition hall is a single-story large space building that can accommodate 4,446 spectator seats, including 3,514 fixed seats and 932 movable seats. The competition venue is equipped with 8 evacuation doors with a net width of 2.20m, two of which Two evacuation doors are connected to the outdoor foyer of the competition hall, and six evacuation doors are connected to the evacuation corridors of the ancillary buildings. The auditorium is equipped with 12 evacuation doors with a net width of 2.20m, including 6 evacuation doors. It is connected to the outdoor foyer of the competition venue, and the six evacuation doors are connected to the outdoor platform on the rooftop of the first floor of the annexed building; the distance from any point in the competition venue and auditorium to the evacuation exit shall not exceed 30m. The training hall has 2 floors above ground and part 1 floor. There are training rooms for basketball, swimming, table tennis, fitness, etc. There are two open evacuation stairwells with a net width of 1.40m.

The stadium is equipped with 6 fire protection zones; one of the fire protection zones is used as a competition venue and auditorium, with a construction area of ??5000m2; each fire protection zone is equipped with at least two safety exits. The gymnasium is equipped with indoor and outdoor fire hydrant water supply systems, automatic sprinkler systems and other fire-fighting facilities and equipment in accordance with relevant national engineering construction fire-fighting technical standards.

Based on the above scenario, answer the following questions.

1. What levels can sports buildings be divided into?

2. What requirements should the fire lane of the stadium meet?

3. What requirements should the evacuation door of the stadium meet?

4. In a certain competition, there were 4,400 people in the auditorium. Seven evacuation doors were designed and the width of each evacuation door was 2.2m. Does it meet the requirements? Why? Give countermeasures.

5． What requirements should the materials for making fixed seats in the stadium meet?

Question 6 (20 points)

A commercial complex has 26 floors above ground and 3 floors underground. The construction land area is 8.95x104m2, and the total construction area is 37.73×104m2, of which the above-ground construction area is 27.08x104m2 and the underground construction area is 10.65x104m2. The first to third floors above ground of the building are designed as indoor pedestrian streets, connected to each other through several atriums. The construction area of ??the pedestrian street is 43,411m2, of which the first floor construction area is 15,922m2. The net width of the pedestrian street is about 11~15m. The basement of the building is mainly used as a garage, mechanical and electrical equipment rooms, and property service rooms; the first floor is mainly used as department stores, anchor stores, indoor pedestrian streets, and street-facing shops; the second and third floors are mainly used as indoor pedestrian streets, department stores, Video games, restaurants, and dance halls; the 4th to 6th floors are mainly used for department stores, restaurants, and movie theaters; the 7th to 26th floors are mainly used for hotels. Except for the fire protection zoning of the indoor pedestrian street, safe evacuation, and the need to use the indoor pedestrian street for evacuation on the first floor of some evacuation stairwells, other fire protection designs of this building meet the current regulations on national engineering fire protection technical standards. In the fire performance-based design evaluation, the fire load inside the indoor pedestrian street is limited by isolating the commercial fire load in the indoor pedestrian street. Set up effective fire detection, automatic fire extinguishing, smoke prevention and exhaust and other fire protection measures, and set the pedestrian street as a "temporary safety zone" to solve problems such as the large area of ????the pedestrian street's fire protection zone and the use of pedestrian streets for evacuation.

Based on the above scenario, answer the following questions.

1. What are the categories of fire hazard sources? List 3 of them.

2. What are the four types of t2 fires? How long does it take for a rapid fire to reach a fire scale of 1MW?

3. For this type of commercial complex building, when conducting fire performance-based design and fire risk assessment, what should be considered in setting fire scenarios? Please list 4.

4. For some reasons, it is difficult to set up a firewall in the atrium. It is necessary to set up fireproof roller shutters in the atrium and floor walkways. How long can the fire resistance limit of the fireproof roller shutters be lower? What requirements should the width of the fireproof roller shutters meet?

5. What are the categories of fire risk sources?

6. Please briefly describe what fire protection measures should be taken to solve the fire protection problem of expanding the fire protection zone area of ??the indoor pedestrian street in this project and using the indoor pedestrian street for evacuation?

Analysis of the first question

1 ． The eccentric and large ends of the horizontal section of the water pump suction pipe should be connected flat on the top of the pipe to avoid air pockets and air leakage.

2. When the fire water supply pipe passes through the wall or floor, a casing must be installed. The length of the casing shall not be less than the thickness of the wall or 50 mm higher than the floor or ground. The gap between the casing and the pipe shall be filled with non-combustible materials. The interface of the pipe shall not be Should be located inside the casing.

3. When arranged vertically, the air inlet of the air blower should be set below the air outlet of the smoke exhauster, and the minimum vertical distance between the two edges should not be less than 3. OO m; when arranged horizontally, the minimum horizontal distance between the two edges should not be less than 10m.

4. Pipe network flushing should be carried out in sections after passing the pressure test. The order of flushing is outdoor first, then indoors; first underground, then above ground; flushing of indoor parts should be carried out in the order of water distribution main pipes, water distribution pipes, and water distribution branch pipes.

The test points come from pages 115 to 116 of the textbook "Comprehensive Ability in Fire Safety Technology".

5． The fire hazard level of the place where the automatic sprinkler system is installed should be medium hazard level I, the water spray intensity should not be less than 6L/min?m2, and the action area should not be less than 160m2.

Analysis of the second question

1. The number of outdoor fire hydrants should be calculated and determined based on the design flow rate and protection radius of the outdoor fire hydrant. The protection radius should not be greater than 150.0m, and the water consumption of each outdoor fire hydrant should be 10 to 151/s. The water consumption of the outdoor fire hydrant of this building is 301/s, so 2 to 3 outdoor fire hydrants should be installed. Outdoor fire hydrants should be evenly arranged around the high-rise building, and should not be concentrated on one side of the building; the number of outdoor fire hydrants on one side of the fire fighting surface of the building should not be less than 2.

2. The fire risk level of this high-rise commercial complex is medium risk level 1, but the fire risk level of its underground garage is medium risk level 11. Therefore, the design flow rate of the automatic sprinkler system of the building is determined according to medium risk level 11. Its sprinkler system The intensity is 8L/min?m2, and the action area is 160m2. The nozzle is a fast-response nozzle with flow coefficient K=80. The nominal operating temperature is 30°C higher than the ambient temperature, that is, a red nozzle of 68°C. A green nozzle of 93°C is selected for the kitchen area. Since the number of sprinklers controlled by each wet alarm valve does not exceed 800, the total construction area of ??the building is 67137.48m2, and the protection area of ??one sprinkler head at medium risk level 11 is 11.50m2. Preliminary calculations indicate that the building needs at least 67137.48/11. 5=5838.04, take 5839 nozzles, and wet alarm valves must be installed at least 5839/800=7.3, take 8. The height of the building is greater than 50m, and there are three floors of basements. When setting up the alarm valve group of the automatic sprinkler system, attention should be paid to the elevation difference between the water supply of each alarm valve group and the lowest position sprinkler nozzle. The height difference should not be greater than 50m.

3. If the fire power supply is provided by a self-contained emergency generator set, since the fire protection power of the building is a first-level load, automatic and manual starting devices must be set up and power supply must be provided within 30 seconds.

4.1) For public buildings with a building height exceeding 50m, the smoke-proof stairwells and fire elevator front rooms should adopt smoke-proof systems with mechanical pressurized air supply. The height of the building is 53.80m, so the smoke-proof stairwell and the front room of the fire elevator should be equipped with a smoke-proof system in the form of mechanical pressurized air supply. In addition to calculating the head loss of the most unfavorable ring pipe, the full pressure of the mechanical pressurized air blower should also have a residual pressure. The remaining pressure values ??should meet the pressure difference between the smoke-proof stairwell and the walkway of 40 to 50 Pa. The pressure difference between the room, the front room of the fire elevator room, the closed refuge floor (room) and the walkway is 25-30Pa.

2) The above-ground part of the building is a commercial complex where people often stay or there are many combustibles, so a mechanical smoke exhaust system should be installed. The underground garage of this building has a construction area of ??more than 1,000m2, so a mechanical smoke exhaust system should be installed.

5． Because the fire elevators should be set up in different fire protection zones, the above-ground construction area of ??the building is 39215.18m2, with 10 floors, and the average area of ??each floor is 3921.518m2. The building height is 53.8m, which is a first-class high-rise and fire-resistant The grade should not be lower than Level 1, then in a Class I high-rise building with an automatic sprinkler system and a fire resistance level of Level 1, the allowable building area of ??the fire protection zone is 3000m2, and 2 fire protection zones should be divided. Therefore, the building should be set 2 fire elevators. The load capacity of the fire elevator should not be less than 800kg, and the running speed from the first floor to the top floor should not exceed 60 seconds.

Analysis of the third question

1.1) The fire hazard category of aluminum powder factory production belongs to Category B. Because its fire resistance level is Level 2, the maximum number of floors allowed is 6. , thus meeting the requirements.

2) Because the edible oil warehouse actually stores liquids with flash points greater than 60°C, the fire hazard category of the stored items in this warehouse is Category C 1. Because its fire resistance level is Level 2, it is at most The allowed number of layers is 5, so it meets the requirements.

3) The fire hazard category produced by the printing and dyeing factory belongs to Category C. Because its fire resistance level is level three, the maximum allowed number of layers is 2, so it meets the requirements.

4) The fire hazard category produced by the packaging factory belongs to Category C. Because its fire resistance level is Level 2, the maximum number of layers allowed is unlimited, so it meets the requirements.

2. Because the load-bearing components of the roof of the clothing factory are flame-retardant components with a fire resistance limit of 0.5h, and the columns are non-combustible components with a fire resistance limit of 2.5h, the fire resistance level should be Level 3. The allowable building area of ??each fire protection zone is 2000m2, and because the factory is equipped with an automatic sprinkler system, the allowable building area of ??each fire protection zone can be doubled according to regulations. Therefore, the construction area of ??each floor of the garment factory is 4000m2, and each floor is divided into a fire protection zone, which meets the requirements.

3. Because the garment factory is a Category C factory, it should meet the requirements for offices and rest rooms in Category C factories. Therefore, offices and lounges set up in garment factories should meet the following conditions: Offices and lounges should be separated from other parts by fire partition walls with a fire resistance rating of not less than 2.50h and floor slabs of not less than 1.00h, and should be separated from other parts by at least Set up an independent safety exit. If interconnected doors need to be opened on the partition wall, Class B fire doors should be used.

4. The clothing factory covers an area of ??more than 3000m2, and a circular fire lane should be set up; when difficulties arise, fire lanes should be set up along the two long sides of the building. The clear width and clear height of the fire lane should not be less than 4m, and the slope of the fire lane should not be greater than 8%. There should be no obstacles between the fire lane and the factory building that would hinder the operation of fire trucks. The circular fire lane should be connected to other lanes at least at two places. If necessary, a middle lane connected to the circular lane should be set up, and the road setting should take into account the turning radius of large vehicles.

5． Because the fire hazard category of the garment factory belongs to Category C, and the fire resistance level is level three, the fire separation distance between the garment factory and the aluminum powder factory, edible oil warehouse, printing and dyeing factory, and packaging factory should not be less than 12m, respectively. 12m, 14m and 12m.

6. Under normal circumstances, the fire separation distance between the garment factory and the four-story aluminum powder factory building with a fire resistance level of Level 2 should not be less than 12m. The following measures can be taken to solve the problem of insufficient fire separation distance:

1) Improve After the fire resistance level of the clothing factory is not lower than Level 2, the minimum fire separation distance between the clothing factory and the aluminum powder factory is 10m.

2) Reduce the production fire risk of the garment factory, improve its fire resistance level, reduce the production fire risk category to Category E, and make its fire resistance level no less than Level 2, then the garment factory will be the same as Category E. The minimum fire separation distance between aluminum powder factories is 1om.

3) Change all the exterior walls adjacent to the aluminum powder factory and the clothing factory into fireproof walls, with no limit on the fireproof distance.

4) Renovate the two adjacent exterior walls of the aluminum powder factory and the garment factory into non-combustible walls, with no exposed combustible eaves. The total area of ??doors, windows and openings on each exterior wall Each is no more than 5% of the area of ??the exterior wall, and when doors, windows, and openings are not opened directly opposite each other, the fire separation distance can be reduced by 25% as required, and the fire separation distance can be 9m.

5) Set up an independent firewall and pay attention to ventilation, smoke exhaust and demolition and firefighting.

6) Demolish the aluminum powder factory building.

Analysis of the fourth question

1. Since the underground garage has a construction area of ??3999m2, is equipped with an automatic fire extinguishing system, and is divided into a fire protection zone, the fire resistance level of the garage should not be lower than Level 2.

2.1) Since the garage is equipped with an automatic fire extinguishing system, the evacuation distance from any point in the garage to the nearest safety exit should not be greater than 60m.

2) Evacuation stairs cannot be used between two adjacent fire protection zones in the garage. When the number of parking spaces is greater than 100 and less than or equal to 300 vehicles, no less than two stairwells should be set up and arranged dispersedly. However, the garage described in the scenario has 101 vehicles parked, so evacuation stairs cannot be used. Two stairwells should be used. Fire compartments must have at least 4 stairs.

3. Turn the water gun (the rotary switch is in the off position) into three positions with the nozzle pointing vertically upward, the nozzle pointing vertically downward, and the axis of the water gun horizontal (if there is a switch, the switch is below the axis of the water gun and in the off position), from the ground (2.0±0.02)m high (from the lowest point of the water gun) free fall to the concrete floor, the water gun falls twice at each position, and then check the water gun, if the fire interface breaks after falling Or if it cannot be operated and used normally, the product will be deemed to be unqualified.

4． Fire emergency lighting should be installed on the wall or shed, and the minimum horizontal illumination on the ground should not be less than 1.01x. Safety exit signs should be set on the top of evacuation exits; evacuation indication signs should be set on evacuation passages and their turns, on walls with a height less than 1m from the ground. The distance between indicator signs on the passage should not be greater than 20m. For fire emergency lighting and evacuation indication signs on evacuation corridors, batteries can be used as backup power sources, but their continuous power supply time should not be less than 30 minutes.

5.1) Since the garage belongs to Category III, its water consumption should not be less than 101/s. The pressure in the system pipeline should ensure that the water nozzles of two adjacent fire hydrants fill the water column and reach any room indoors at the same time. parts.

2) The water column of the fire hydrant nozzle in the garage should not be less than 10m, and the distance between adjacent indoor fire hydrants on the same floor should not be greater than 30m.

3) Indoor fire hydrants should be installed in a place that is obviously easy to access, so that users and fire brigade can find and use them in time. The hydrant should be 1.1m from the ground, and its water outlet direction should be downward or downward. Perpendicular to the wall where the fire hydrant is installed.

Analysis of Question 5

1. Sports buildings can be divided into four grades: special grade, grade A, grade B and grade C.

2. The fire lane setting of the stadium should meet the following requirements:

1) According to the "Sports Building Design Code", the fire lanes around the sports building should be connected; when fire trucks cannot approach according to regulations due to various reasons When building a building, one of the following measures should be taken to meet the need for fire fighting:

① The fire truck is close to the main body of the building in the lower space of the platform.

②The fire truck drives directly into the building.

③The fire truck reaches the upper part of the platform to approach the main body of the building.

④A fire hydrant is provided on the upper part of the platform.

2) Because the stadium can accommodate 4,446 spectator seats; 3,000 spectators, the stadium should be equipped with a circular fire lane. The clear width and clear height of the fire lane should not be less than 4m. The slope of the open space for fire trucks to stay should not be greater than 3%. There should be no obstacles that hinder the operation of fire trucks between fire lanes and civil buildings. The circular fire lane should be connected to other lanes at at least two places. The road surface of the fire lane, the firefighting operation site and the pipes and underground ditches below should be able to withstand the pressure of large fire trucks. Fire lanes can use traffic roads, but they should meet the requirements for the passage and parking of fire trucks.

3. Evacuation doors should be swing doors, and sliding doors, rolling shutter doors, hanging doors, and revolving doors should not be used. Evacuation doors in densely populated places that need to control the free entry and exit of people at ordinary times should ensure that they can be easily opened from the inside without using any tools such as keys in the event of a fire, and signs and usage tips should be set in prominent locations.

4． Not meeting the requirements.

The calculation process is as follows:

The number of people passing through each evacuation door: 4400/7=628.6, take 629 people.

The width of each evacuation door is 2.2m, which is the width required for four streams of people.

The evacuation time required to pass through each evacuation door is: 629/(37x4)=4.25min; 4min, because the time for people to evacuate from the auditorium is generally controlled at 3 to 4 minutes. Each evacuation door The average number of people evacuated generally does not exceed 400 to 700 people. If 8 doors are set up, the requirement is met, because 4400/8=550, 550/(37x4)=3.72minlt;4min.

5. Fixed seats should be made of refractory materials with a smoke density index of less than 50.

Analysis of Question 6

1. Fire hazard sources are divided into first-category hazard sources and second-category hazard sources. The first category of hazard sources includes combustibles, fire smoke and toxic and harmful gases produced by combustion. The second type of hazard sources includes automatic fire alarm systems, automatic fire extinguishing systems, emergency broadcasts, evacuation systems, etc.

2. T2 fires include slow fires, medium fires, fast fires and extremely fast fires, which respectively represent the fire scale that can reach 1MW within a certain period of time. The time required for fast fires to reach the fire scale of 1MW is 150s.

3. For this type of commercial complex building, when conducting fire performance-based design and fire risk assessment, the fire scene setting should consider the following:

1) Fire source location.

2) Fire growth model.

3) Whether the automatic sprinkler system is effective.

4) Whether the smoke prevention and exhaust system is effective.

4． For some reasons, it is difficult to set up a firewall in the atrium. It is necessary to set up fireproof roller shutters in the atrium and floor walkways. The fire resistance limit of the fireproof roller shutters cannot be less than 3h.

When the width of the fire separation part is not greater than 30m, the width of the fire prevention roller shutter shall not be greater than 10m; when the width of the fire separation part is greater than 30m, the width of the fire prevention roller shutter shall not be greater than the width of the fire separation part. 1/3, and should not be larger than 20m.

5. Fire risk sources are divided into objective factors and human factors.

(1) Objective factors:

1) Meteorological factors cause fires.

2) Electrical fires.

3) Inflammable and explosive items cause fire.

(2) Human factors

1) Fire caused by careless use of fire.

2) Unsafe smoking causes fires.

3) Man-made arson.

6.1) Solve the problem of excessively large fire protection zones.

① Remove the sources of danger and divide the two sides of the pedestrian street into shops with an area of ??no more than 300m2. The side facing the pedestrian street should be separated by a maintenance structure with a fire resistance rating of not less than 1.00h.

② Indoor pedestrian streets should not be equipped with combustible materials and should use non-combustible or flame-retardant materials.

③Indoor pedestrian streets should be equipped with effective smoke exhaust measures and automatic fire extinguishing measures.

2) Solve the problem of safe evacuation.

① Indoor pedestrian streets should take effective natural smoke exhaust measures, and the effective area of ??the natural smoke exhaust outlet should not be less than 25% of its ground area.

②The walking distance from the pedestrian street to the nearest outdoor safe location should not be greater than 60m.