Case Analysis of Class I Fire Engineer in 2020 Practice 4.24 times a day.

A complex building has three floors above ground, with a building height of 17m. Set a fire control room on the first floor of the building. The fire control room uses Class B fire doors to enter the lobby on the first floor. The fire control room is equipped with two fire alarm controllers, a fire linkage controller, a graphic display device, a user information transmission device and a fire emergency power supply. All the fire fighting equipment is in the fire control room? One? The lines are arranged in zigzag, with the operating distance of 2.5m from the wall in front of the equipment panel, and the channel of 1.2m behind the equipment, and the monitoring equipment of the comprehensive building is arranged on the other side of the channel.

The building area of the comprehensive building is about 150m? The height of the building is 4.5m, and each office is equipped with two point smoke detectors; the kitchen, dining room and Kara 0K hall are equipped with two point smoke detectors and 1 point temperature detector; the distance between the point temperature detector and the air supply outlet of the air conditioner is1m; A combustible gas detector is installed on the ground of the gas-fired boiler room in the basement to detect natural gas leakage.

The building is equipped with a fire emergency broadcast system and background music. The bottom of the broadcasting horn is 2.2m above the ground, and it will automatically switch to emergency broadcasting in case of fire. In case of fire, start the fire accident broadcast according to the evacuation order. When there is a fire on the first floor, first open the first and second floors. When there is a fire on the second and above floors, first open the fire floor and the upper and lower floors.

The building is equipped with ventilation, air conditioning, pressurized air supply and smoke control system and mechanical smoke control system. The blower and exhaust fan are set in a separate machine room, separated from other parts by a fire partition wall with a fire resistance limit of 2.00h, a floor of 1.50h and a Class B fire door. When two detectors on any floor of the building give an alarm, the air supply outlet, smoke exhaust outlet, fan and smoke exhaust fan of that floor will be started at the same time within 15s, and the ventilation and air conditioning system unrelated to smoke exhaust will be closed within 40s.

After receiving the action signals of any two independent smoke detectors in the fire area, the fire shutter of the evacuation passage descends to the floor.

According to the above materials, answer the following questions: (***20 points)

1. Point out the problems existing in the installation of fire alarm system facilities such as fire detectors and emergency broadcasting in this case, and explain the reasons.

2. Point out the problems existing in the linkage design of emergency broadcast and fire shutter in this case, and explain the reasons.

3. Point out the problems existing in the design of smoke control and fire control linkage in this case, and explain the reasons.

4. Point out the problems existing in the setting of fire control room, smoke control room and other rooms in this case, and explain the reasons.

Reference answer and analysis

1. Answer 1) Building area 150m? The installation of two smoke fire detectors in the office does not meet the requirements. Reason: The ground area exceeds 80m? When the room height is not more than 6m, the protection area of smoke detector is A=60m? , correction coefficient K= 1, each room should be set at least N=S/(K? A)=3 smoke fire detectors.

2) The installation of smoke fire detectors in the kitchen of the complex building does not meet the requirements. Reason: The kitchen should be equipped with a temperature-sensitive fire detector.

3) The combustible gas detector installed on the ground of the gas-fired boiler room detects natural gas leakage, which does not meet the requirements. Reason: The combustible gas detector with gas density less than air density should be set at the top of the protected space.

4) The distance between the point temperature-sensitive fire detector and the air supply outlet of the air conditioner is 1m, which does not meet the requirements. Reason: The horizontal distance between the point detector and the air supply outlet of air conditioner should not be less than1.5m..

5) The height of the bottom edge of the broadcast speaker from the ground is 2.2m, which does not meet the requirements. Reason: The height from the bottom of the wall-mounted speaker to the ground should be greater than 2.2m.

2. Answer 1) When there is a fire, turn on the fire accident broadcast according to the evacuation order, and turn on the first and second floor broadcasts when there is a fire on the first floor; When there is a fire on the second floor and above, the fire floor and the upper and lower floors should be broadcast first, which does not meet the requirements. Reason: The linkage control signal of the fire emergency broadcasting system should be sent by the fire linkage controller. When the fire is confirmed, it should be broadcast to the whole building at the same time.

2) After the fire shutter of the evacuation passage receives the action signal of any two independent smoke fire detectors in the fire partition, the shutter descends to the floor, which does not meet the requirements. Reason: The linkage control of the fire shutter installed on the evacuation passage should meet the requirement of controlling the fire shutter to descend to the ground 1.8m after receiving the alarm signal from any two independent smoke fire detectors or any smoke fire detector dedicated to the linkage of the fire shutter; The alarm signal of the temperature-sensitive fire detector dedicated to the linkage fire shutter should be linked to control the fire shutter to descend to the floor.

3. Answer: When two detectors on any floor of the building give an alarm, that is, the air supply outlet, smoke exhaust outlet, blower and smoke exhaust fan of that floor are started at the same time within 15s, and the ventilation and air conditioning system unrelated to smoke exhaust is turned off within 40s, which does not meet the requirements.

Reason: The linkage control design of smoke control system should meet the alarm signals of two independent fire detectors or a fire detector and a manual fire alarm button in the fire protection zone where the pressurized air supply outlet is located as the linkage trigger signal for opening the air supply outlet and starting the pressurized fan. The fire-fighting linkage controller shall control the opening of the pressurized air supply tuyere and the start of the pressurized fan in the front room of the relevant floor within 15s.

The linkage control design of smoke exhaust system should meet the following requirements: the alarm signals of two independent fire detectors in the same smoke prevention zone are used as linkage trigger signals for opening smoke exhaust ports, windows or valves, and the action signals for opening smoke exhaust ports, windows or valves are used as linkage trigger signals for starting smoke exhaust fans. All smoke exhaust valves, smoke exhaust ports, smoke exhaust fans and air supply facilities in the corresponding smoke prevention zone shall be opened together within 15s and automatically closed within 30s.

3) There is a 1.2m channel behind the equipment, and the monitoring equipment of the comprehensive building is arranged on the other side of the channel, which is not in conformity with the regulations. Reason: In the fire control room shared with other weak current systems in the building, the fire fighting equipment should be set centrally, and there should be obvious intervals between them.

4) The blower and exhaust fan are set in a separate machine room, and the fire partition with a fire resistance limit of 2.00h, the floor of 1.50h, and the Class B fire door are separated from other parts, which is not in conformity with the regulations. Reason: The special machine room should be equipped with a separate blower and smoke exhaust fan, and the doors on the partition wall should adopt Class A fire doors.