2. In the design of bus linkage system, the manual direct control of main fire extinguishing equipment is not considered in the fire control room. Such as a CO2 gas fire extinguishing system.
3. The fire hydrant button is not used to directly start the water pump.
4. In the fire fighting linkage, the feedback signal of non-fire power cut-off and elevator landing at last is not considered.
5. The alarm system only considers protective grounding, and working grounding is not designed.
6. The location of the fire control room is not suitable. (Part of the design is on the second floor)
7. Do not consider the fire power supply of the automatic fire alarm system in the fire control room.
8. Do not use alarm products with direct manual control function.
According to the specification, the fire-fighting linkage control equipment should be provided with direct manual control function for important fire-fighting linkage equipment, which can display the water pump start signal. while
The fire-fighting linkage control equipment adopts bus control mode and should have at least six groups of direct output contacts.
9. In some two-bus alarm systems, no short-circuit isolator is designed.
10, and spare power amplifiers are not considered in most projects.
1 1. In many engineering designs, some equipment rooms are not equipped with intercom phones.
12, fire linkage logic disorder.
Reason:
1) Some designers don't understand the fire linkage logic correctly. The performance is as follows: water flow indicator, fire detector, pressure switch and door alarm before starting the spray pump; Press the fire hydrant button, fire detector and door alarm to start the fire pump; Manual alarm button, fire detector and door alarm to start the shutter door and so on. The linkage logic relationship is described in detail in GB50 166-92 Code for Installation and Inspection of Automatic Fire Alarm System.
(1) alarm signals: detector alarm, water flow indicator alarm, etc.
(2) Alarm confirmation signal: The most reliable confirmation is manual confirmation, which can also be monitored by TV. In the system design, the AND gate signal after two groups of detectors or two different types of fire detectors alarm at the same time is generally used as the method of "fire confirmation". In this paper, "alarm after fire" refers to the alarm of detector or loop detector. "After the fire is confirmed" refers to the AND gate signal given by two detectors.
(3) Control of the shutter door
For the fire shutter on the evacuation passage, the descent shall be controlled according to the following procedures:
A) After the smoke detector moves, the roller shutter drops to1.8m; From the ground (floor);
B) After the temperature detector moves, the roller blind will descend to the end;
Fire shutter is used for fire separation. After the fire detector moves, the shutter should be lowered to the bottom.
2) The concept of connection mode of linkage control system is unclear.
There are two common wiring modes for fire alarm system and fire linkage system.
(1) is the combination of fire alarm system and fire linkage system, that is, there are both fire alarm detectors and output modules of linkage fire control facilities in the same loop;
(2) The two systems are independent. The alarm loop only has an alarm detector and an input module for receiving signals, and the linkage loop is an output module.
3) Do not understand "manual" in linkage control system.
Code for Design of Automatic Fire Alarm (GBJ-50 1 16-98) requires that fire-fighting facilities, such as fire pumps, spray pumps and smoke exhaust fans (including positive pressure fans) should be hardwired in addition to the above functions. That is, in addition to the fire linkage control bus, there should be a single non-coding control line between the fire control facilities and the fire control room.
4) The leader or chief engineer of the fire self-inspection team of each design institute failed to conduct a comprehensive review of the fire water, electricity and heating construction drawings.
Fire electrical system 1. In the primary load power supply system, if any of the two independent high-voltage unit circuits fails, the high-voltage side bus switches should be interlocked, and most of the switches are designed to be manual.
2. In a first-class load system with a high-voltage power supply and a self-contained generator, when the mains voltage fails, the self-contained generator can only be manually put into the low-voltage side bus for power supply, which delays the power supply time.
3. The power box of fire fighting equipment is powered by two channels. Only one route of the substation is powered by high voltage, and the other route is powered by its own generator, which is connected to the low voltage bus through the double-throw switch. The above three points are not only related to the understanding of the first-class load, but more importantly, the local power supply department is afraid of affecting the wiring of the distribution network, endangering the safety of the distribution network, and causing the self-contained generators to switch on in different periods.
4. A class of high-rise buildings should be equipped with automatic starting devices, which can supply power within 30s, but most generators are not equipped with voltage monitoring devices and can only be started manually. This is mainly because substations and generators are not designed with necessary automatic interlocking devices, and more importantly, some power supply departments do not agree to supply power by themselves.
5. Some control boxes are not designed with lead-out terminals and corresponding equipment that can be directly started manually in the fire control room. This is mainly because the designer has not designed the schematic diagram, and at the same time, he has not deeply understood the direct manual control device of important fire fighting equipment.
6. Some standby fire pumps are used in fire hydrant systems and automatic sprinkler systems, so that the standby pumps cannot be put into operation according to system failures. The lack of communication between these fire water supply professionals is related to the understanding of the code.
7. Some control boxes were not selected according to the standards recommended in Atlas of Building Electrical Installation Engineering, but the old XJ0 1- 1 control boxes were selected, which led to the failure of the main pump and forced to go to the pump room to start the standby pump.
8. The fire control room cannot monitor the power supply of important fire control facilities, because the fire control box is not designed with a power supply monitoring device.
9. Some important fire power supply circuit switches are not selective. When the fire pump is started, the automatic switch of the control box will not trip due to the large starting current, but will jump to the power supply side or the low-voltage bus side of the distribution room. When selecting the standard control box, the action current (or sensitivity) of the power supply system and the automatic switch is not well checked, which may easily cause the reverse action current of the load to be greater than the head-end current, leading to over-step tripping.
10. Fire-resistant cables are not used for power supply lines of water pumps, smoke control fans, fire elevators and other equipment.
1 1. The centralized power supply evacuation lighting in the stairwell cannot be automatically lit in case of fire.
12. The emergency lighting time is insufficient and the illumination is low in the places (such as power distribution room, water pump room, etc.) that continue to work in case of fire. ). Fire hydrant water supply system 1, fire pool
(1) The effective capacity of the fire pool is too small.
The duration of building fire and the water consumption of indoor fire hydrant are wrong. After the renovation of the old project, adding sprinkler system did not increase the capacity of the pool.
(2) There are no special fire-fighting technical measures for the shared pool.
In some projects, fire water is shared with production and living pools to prevent water quality from deteriorating; However, no special fire protection measures were designed. There are three common special measures for shared pools: technical measures for shared pools.
(3) Non-separation measures for large-capacity pools
If the fire pool exceeds 1000m3, the corresponding building is more dangerous or important. After the fire pool is divided into compartments, there is still half of the fire water source when cleaning the fire pool to ensure the safety of the building.
2. Fire pump
(1) The flow of fire pump is small.
The flow of fire pump is too small to meet the requirements of indoor fire water consumption.
(2) The lift of the fire pump is too large.
The fire pump has a large lift, which is not conducive to the work of the pipe network.
(3) A group of fire pumps has only one suction pipe.
In some projects, a group of fire pumps has only one suction pipe. When the suction pipe was overhauled, the whole system was paralyzed.
(4) A group of fire pumps has only one outlet pipe.
Just like the suction pipe of a fire pump, if a group of fire pumps has only one outlet pipe, the reliability of the fire protection system will be reduced.
(5) There is no pressure gauge, test drain valve and pressure relief valve on the outlet pipe of the water pump.
The outlet pipe of the fire pump is equipped with a pressure gauge and a test drain valve. When the fire pump is at the inspection station, the outlet water of the fire pump cannot enter the pipe network, so that the pipe network is protected from overpressure and water hammer. Because the pipe network will be overpressure after starting the fire pump in the initial fire, and the water hammer effect will occur, and the water hammer effect will also occur when stopping the pump. After the pressure relief valve is installed on the outlet pipe, the pressure can be relieved and the water hammer effect can be reduced.
(6) The water diversion device is set incorrectly
① There is a water separator on the suction pipe,
(2) The suction pipe is equipped with a bottom valve, and the high water tank is filled with water seepage. In the fire engineering inspection, we found that there are three kinds of non-fires.
(7) The diameter of the water pump suction pipe is small.
In some designs, the pipe diameter is too small, and the flow rate of the pump can not reach the design value.
3, pressurization facilities
(1) The flow of the booster pump is too large.
4. Water pump adapter
(1) The distance between the water pump adapter and the outdoor fire hydrant or the water inlet of the fire pool is more than 40m.
(2) The number of water pump adapters is small.
(3) The water pump adapter has no partition.
5. Setting of pressure reducing device
(1) There is no pressure relief device when the dynamic pressure at the bolt mouth is greater than 0.5Mpa.
(2) For some designs, such as office buildings, the pressure plate used is D/d=65/ 14 and B2-1f.. After starting the fire pump, the measured dynamic water pressure is 0. 12Mpa, which makes the water column < 10 m, which is not conducive to fire fighting.
6. Fire hydrant button
(1) The function of the fire hydrant button is not normal.
There are four types of common mistakes.
A, fire hydrant button can't directly pump water, only through the linkage controller to start the fire pump.
B there is no confirmation signal after the fire hydrant button is started.
C, fire hydrant button can't alarm, display position.
D, fire hydrant button adopts 220V high-pressure pump.
(2) The fire hydrant box of the temporary high-pressure water supply system is not provided with a direct pump start button.
7. Fire water tank
(1) The shared water tank on the roof is directly connected to the fire fighting pipe network without water pipes.
(2) The shared water tank has no special fire water measures.
(3) There is no one-way valve on the outlet pipe of the fire water tank.
8. There is no test fire hydrant for inspection on the roof.
Automatic sprinkler system
1, fire pool (see fire hydrant system)
2. Fire pump (see fire hydrant system)
3, voltage stabilizing system
(1) Selection of stabilized pump The flow of stabilized pump is too large in many projects.
(2) The position of the pressure stabilizing pump
Some designers set up a pressure-stabilizing pump at the high water tank, which is connected to the top of the riser of the nearby automatic sprinkler system. The problem is that when the nozzle is heated and exploded, the pressure behind the valve decreases. After the pressure stabilizing pump is started, it can only increase the pipe network pressure behind the wet alarm valve, so the valve disc can't be opened, so the pressure switch has no signal to start the spray pump.
4. Water pump adapter
(1) setting of water pump adapter
(2) The number of pump adapters is relatively small.
5, the setting of pressure relief device Some designers did not consider the design of automatic sprinkler system in high-rise buildings.
6. Wet alarm valve
(1) setting of wet alarm valve
Many projects are not fully considered when designing the position of alarm valve.
(2) Water supply control valve
Some projects are designed without water supply control valves.
7. Water flow indicator
A signal valve should be installed in front of the water flow indicator, and its distance from the water flow indicator should not be less than 300mm, and most projects do not design signal valves.
8. Terminal test equipment
The terminal test device includes a test valve, a pressure gauge and a drain pipe, and the test pipe diameter is not less than 25mm. In many projects, the terminal tests the diameter of the equipment.
9. After the system linkage test, open the test valve, and the reading of the pressure gauge should be no less than 0.049MPa. During the water discharge test at the most unfavorable point of many projects, the reading of the pressure gauge is less than 0.049MPa, which is because the hydrodynamic pressure at the most unfavorable point is not considered in the design.
10, nozzle
A nozzle should be set under the ventral surface of the air duct with a width greater than 1.2m, but most design units have omitted this item in the countersignature of work types. When designing the nozzle layout, designers should not only consider meeting the requirements of the above specifications, but also consider that the nozzle should not be too close to the high-power heating lamp and the tuyere of the ventilation pipe, so as to avoid misoperation and water spraying caused by the heat emitted by the high-power heating lamp after the system runs; When the nozzle is too close to the air supply outlet to extinguish the fire, the sprayed water is blown away from the normal spraying range by the wind from the air outlet of the ventilation pipe. Therefore, designers should consult other professional designers when designing nozzle layout.
1 1 fire water tank
See fire hydrant system in points (1), (2), (3) and (4).
(5) The vertical distance between the check valve on the outlet pipe of the fire-fighting water tank and the bottom of the water tank is too small (generally less than 1m), so the water flow indicator cannot give an alarm during the water discharge test.
12, pressure relief valve Some projects did not install a pressure relief valve on the water pump outlet pipe.
13, fixing bracket and fixing bracket
Designers calculate the load while designing the automatic sprinkler system, and design the special bearing bracket at the bottom of the water distribution riser according to this value. At the same time, they should check whether the building structural members can bear the load transmitted by this bracket together with the designers of building structure specialty.
14. Selection of dense packing between casing and pipeline. Designers should choose casing packing when designing automatic sprinkler system. It is best to choose glass fiber cloth instead of asbestos as the gap filling material of casing.
15, the hydraulic alarm bell of the pressure switch gives false alarm, and some false alarm problems are often caused by design reasons.
(1) is directly supervised by municipal water affairs. Because the pressure of municipal water fluctuates greatly, the wet alarm valve is essentially a check valve, which only allows water to flow in one direction. When the municipal water is at low pressure and the wet alarm valve is closed, then when the municipal water pressure rises, p1f1>; In P2F2, the wet alarm valve opened, causing false alarm.
(2) Stabilize the voltage with a stabilizing pump. If the water supply of the pressure stabilizing pump is gentle, and the disc always opens at a small angle to supply water to the pipe network, there will be no "false alarm". If the water replenishment rate is too high, the valve disc will open at a large angle at the beginning of water replenishment, that is, a false alarm will appear.
(3) The false alarm caused by setting the booster pump system booster pump is the same as that caused by the pressure stabilizing system.
The foam fire extinguishing system 1 and the foam mixed liquid branch control valve are close to the storage tank, so it is not easy to operate.
2. There is no foam plug on the mixed liquid pipeline.
3. The amount of mixed liquid is calculated without considering the amount of foam fire hydrant and the volume of pipeline.
4. There is no pressure relief device at the lowest part of the pipe network.
5. There is no automatic exhaust valve at the top of the road.
Gas fire extinguishing system
1, and the fire extinguishing intensity and dosage were not accurately calculated.
2. Less consideration is given to the compressive strength of surrounding structures.
3. Less consideration is given to the isolation requirements of protected areas.
For the protection zone set on the third floor, the protection zone above the ceiling and below the floor should be strictly separated according to the requirements of large space (below the ceiling). For single-layer sprinkler layout: the separation specification of the part above the ceiling is not clear, which depends on whether the space above the ceiling is considered in the design quantity of fire extinguishing dose.
4. Less consideration is given to the combined arrangement of detectors.
For the detector under the floor, due to the influence of air flow after air supply from air conditioner, the detector should be installed upward.
5. Linkage problem of gas fire extinguishing system
The corresponding functions such as linkage control, opening closing and fan stopping are not considered in the system design.
6, gas fire smoke linkage control.
The essence of gas fire extinguishing is to release fire extinguishing gas in the protected area, and put out the fire after the concentration reaches a certain value. Obviously, when a fire breaks out, the gas fire extinguishing place should be closed, and the smoke exhaust facilities should not be opened except doors, windows and ventilation facilities. This is different from the general fire. In modern architecture, there are many buildings with fixed window sashes such as glass curtain walls, some of which are closed buildings designed according to the functional requirements of cleanliness and protection, some are places with mechanical smoke exhaust facilities, and some are places with gas fire extinguishing devices. Obviously, gas fire extinguishing places have smoke exhaust facilities. If the code is not analyzed, it is required that the smoke exhaust facilities be linked and controlled to open in case of fire. From the point of view of fire fighting effectiveness, it is unreasonable to do so. Therefore, it is necessary to analyze the design of standardized use places in detail.
Fire separation system 1. Fire detectors and manual control buttons are not set on both sides of the fire shutter used in the evacuation passage.
2. The fire shutter doors on the evacuation passage did not automatically control the descent according to the following procedures (the fire shutter doors in the design generally descend to the end).
(1) When the smoke detector operates, the falling distance of each roller shutter from the ground (building) is1.5 ~1.8m..
(2) After the temperature detector is moved, the roller shutter drops to the bottom.
3. After the fire detector moves, the fire shutter used for fire separation does not drop to the end.
4. For the fire roller blinds used as fire separation in the same fire zone, there is no group drop of multiple roller blinds after the fire detector moves.
5. The fire shutter control device is not powered by the special fire power supply. The fire control room cannot display the feedback signal after the fire shutter action.
6. Integral roller shutter is not protected by water curtain. Smoke control and extraction system 1, mechanical smoke extraction system has a small smoke output, and mechanical smoke prevention system has a small positive pressure air supply.
2. There are no mechanical smoke prevention facilities in the smoke prevention stairwell and shared front room of high-rise buildings that do not have natural smoke exhaust conditions.
3. The stairwell and front room of a class of public buildings with a building height of more than 50m and residential buildings with a building height of more than 100m adopt natural smoke exhaust, without mechanical smoke prevention facilities.
4. The basement with mechanical smoke exhaust is not provided with an air supply system with an air supply volume not less than 50% of the smoke exhaust volume. 5. The smoke outlet and smoke outlet of mechanical smoke exhaust system in the basement cannot be switched in linkage. 6. When the smoke outlet and the air supply valve are opened, the fan cannot be linked to start.
7. The air duct of the ventilation and air-conditioning system passes through the partition walls and floors of fire-proof zones, ventilation and air-conditioning rooms and important or high-risk rooms, and there is no fire valve. 8, kitchen, bathroom, toilet and other vertical smoke exhaust pipes, did not take measures to prevent fire backflow, did not set fire dampers on the branch pipes. This is often overlooked by many designers. 9. The smoke exhaust fan can't be stopped by remote control, and there is no direct manual control. Most of the remote control of the exhaust fan can be started, but it can't be stopped remotely. 10, the feedback signals of several air supply valves (smoke outlets) on the same floor should not be connected in series. 1 1. There is no smoke exhaust fire damper at the inlet of the smoke exhaust fan and the smoke exhaust branch pipe. The smoke exhaust fire damper is not interlocked with the smoke exhaust fan and can be automatically closed. In addition, in order to prevent fireworks from spreading vertically and spreading to the floor where the smoke exhaust fan is located (generally on the top floor), an automatic closing smoke exhaust fire damper should be installed at the entrance of the smoke exhaust fan. 12. The air supply outlet is on the high side and the smoke exhaust outlet is on the low side. 13, Class I high-rise buildings and Class II high-rise buildings with building area exceeding 100m2 are not equipped with mechanical smoke exhaust system. 14, Class I and Class II high-rise buildings with a building height greater than 32m have no direct natural ventilation, and the inner walkways with a length greater than 20m or those with direct natural ventilation but a length greater than 60m have no mechanical smoke exhaust system.
15. The fresh air inlet of the positive pressure air supply system is set incorrectly. A section of air duct should be connected at the smoke outlet, so that the smoke outlet is higher than the fresh air inlet of the air supply system. In order to prevent accidents, it is necessary to set a smoke detector at the entrance of the blower to interlock with the blower. Once the smoke invades, the blower should stop running immediately.
16. Some forerooms (or shared forerooms) of podium buildings in high-rise buildings without natural smoke exhaust conditions should not be equipped with local mechanical smoke exhaust facilities, but with local positive pressure air supply system. 17, the positive pressure air supply system in the front room of the smoke prevention machine room should be provided with a check valve or an electric valve interlocked with the fan opening on the suction pipe of the booster fan; The mechanical smoke exhaust system in the atrium should also be provided with a check valve or a normally closed smoke exhaust valve (which will be opened when the smoke exhaust fire valve is linked) 18. The smoke-proof stairwell and the shared front room adopt the same pressurized air supply system, and there is no automatic pressure difference adjustment device on the branch air duct leading to the shared front room. 19. The design position of smoke control and exhaust fan is improper. 20. The suction port of the mechanical pressurized air supply system is not provided with a check valve or an electric valve interlocked with the fan.