【 Weak current College 】 several examples of fire design flaws---Power By 【 China power house network 】

Automatic fire alarm system
1, in the electrical construction drawing design description is not accurate in articulated linkage logical relationship.
2, in the bus system linkage system, fire control room did not consider the manual fire extinguishing equipment directly control key. For example, the CO2 gas fire extinguishing system.
3, fire hydrant button doesn't consider design direct cycle pump circuit.
4. in the fire, was not considered non-fire power of cutting and elevator landing end fankui signal.
5. alarm system only consider protection grounded, no design work grounded.
6, fire control rooms set location. (Some design on the second floor)
7, does not consider eliminating control room for automatic fire alarm system of fire power.
8, do not use direct manual control function of alarm products
Specification: fire control equipment should be provided on the important fire equipment directly hand control function, can display the pump start signal. When fire control equipment use bus control should also have at least six group directly output contacts
9. in some second bus alarm system, not design short circuit isolator.
10, the majority of the project at design time without considering setting up an alternate amplifiers.
11, in a number of engineering design in some of the device is not set on the phone.
12, fire logic programming chaos
Reason:
1) some designers to understand the logic of fire is not correct. Performance: flow indicator and fire detectors and alarm pressure switches and door before start spraying pump; fire hydrant button and fire detector and door alarm fire pump starts; manual alarm button and fire detector and door alarm after the shutter, and so on. While GB50166-92 the automatic fire alarm system installation inspection code provisions set out in detail in the notes to the combined logical relationship.
(1) alarm signals: a detector alarm, water flow meter and alarm, etc.
(2) alarm acknowledgement signal: the most reliable confirmation is artificial confirmation, or you can use the TV monitor. In system design, which may be of two sets of probes or two different types of fire detectors and alarm "and" door signal as confirmation of the "fire" method for clarity, after the fire alarm ", refers to a detector or a loop detector alarm. "Fire confirmed", refers to two detector alarm "and" door signal is issued.
(3) shutter control
For evacuation channel fire shutter, should use the following procedure to control:
A) smoke detector actions after the shutter down to distance (floor) surface 1.8m;
B) thermal detectors actions after the shutter down to the end;
Used for fireproofing fire shutter, fire detectors action, shutter should drop to the end.
2) coordinated control system wiring pattern concept is not clear
Fire alarm systems and fire protection systems, there are two common ways of connecting.
(1) the fire alarm system and fire protection systems into one, i.e. in the same loop of existing fire alarm detectors, linkage fire facilities action output module;
(2) are two separate systems, alarm circuit only alarm detector and signal input module linkage loop are output module.
3) coordinated control system "manual to understand the impervious
The automatic fire alarm design code (GBJ-50116-98), the requirements for fire-fighting facilities, such as fire pumps, spray pumps, smoke exhaust fan (including positive pressure ventilator) in addition to the above features should also have the hard wiring. That is, in fire-fighting and fire control rooms except fire linkage control bus, a single set of non-coded control cord.
4) Design Institute fire since the audit team leader or chief engineer on the fire-fighting water, electricity, warm drawings without comprehensive auditing.
Fire-electrical system
1. at the level of power supply system, 2-channel independent power supply of high-voltage units loop, either circuit failure, its high pressure side of the Bus Coupler switch should interlock input, but most of the design of this switch are manually.
2. when all the high-voltage power supply and the other way to bring their own generator powered level load system, when the power supply voltage failure, but their own generators often rely on manual inputs to the low voltage side of bus power supply, this power supply time delays.
3. fire-fighting equipment power supply unit for two ways power supply, power supply only one high-voltage substation, another way to bring their own generators, generator by DPSS knife switch access for low-voltage bus. The above three points in addition to the level of understanding about the load, more importantly, the impact of local power supply sector is afraid, threatening the distribution network of distribution power, and power generator non-synchronous switching, etc.
4. a class of high-rise building electric power generation, should be equipped with automatic start unit and power supply in the 30s, but most of the generator is not set voltage monitoring devices, it can only rely on manual start. This is mainly a substation and generators are not design the necessary automatic interlocking device for money, some of the electricity sector do not agree to the automatic switching power supply.
5. some of the control box is not design in fire control room leads directly to manually start the Terminal and the appropriate equipment. This is mainly because the designers did not design schematics, at the same time on the important direct fire-fighting equipment should be set manually control devices understand not deep.
6. preparation of a fire hydrant system and pump for spraying system shared by pump, under system failure, the choice may be put into operation. The lack of fire-fighting water supply professional communication and understanding of the specification.
7. some of the control box is not in accordance with the building electrical installation project Atlas of the recommended standard selection and selection of old-fashioned XJ01-1 control box, leaving the main pump failure, can only go to the pump house scene started by pump.
8. fire control rooms cannot monitor important fire facilities, power supply, because fire control box is not design power monitoring device.
9. the important fire power supply circuit switch does not have a choice when you start a fire pump, due to the startup current, control box automatically switch is not tripping, but leapfrog to skip to the power supply side and or distribution, low-voltage bus side. When you select a standard control box, is notVery good check of power supply system and automatically switches the current (or sensitive), very easy to load down current is greater than the first end-to-current, and the trip.
10. water pump, blower, fire smoke control equipment, its lift power supply line does not use fire-resistant type cable.
11. staircase centrally operated evacuation lighting, fire does not automatically light up.
12. continue to work in the fire place (such as distribution, a water pumping station, etc.) is not enough time for emergency lighting and illumination.
Fire hydrant to water system
1, fire water tank
(1) effective fire water tank capacity is small
The duration of the building, fire hydrant water selection error. Old renovation, addition of spray system, water tank capacity is not increased.
(2) combined with pool no fire dedicated technical measures
Some works of fire-fighting water and water production, life and to prevent the deterioration of water quality; but not design fire special measures. Combined pool of dedicated measures commonly used are the following picture shows three: shared pool of technical measures
(3) large capacity water tank without distinction that measures
Fire water tank fire more than 1000m3, corresponding to the importance of building hazard or greater, a fire water tank compartment measures, fire water tank cleaning during the half of the fire water to ensure the safety of the building.
2. fire-fighting pump
(1) small fire pump flow rate
Fire pump flow rate is small does not meet the requirements of the indoor fire water.
(2) fire pump lift too big
Fire pump lift large side adverse the pipeline work.
(3) a set of fire control pump suction pipe with only one root
There is a group of engineering fire pump only one suction pipe, when suction pipe inspection, the entire system crashes.
(4) a set of fire control pump only one outlet
And the fire pump's suction pipe, if a group of fire pumps only one outlet, you will reduce the fire protection system reliability.
(5) water pump outlet on the pressure gauge, no test on the water valve, pressure relief valves
The fire pump discharge pipe fitted with a manometer, test on the water valve, pump at checkpoints, you can make the fire pump effluent does not enter the supply pipe network against overpressure and water hammer. As a result of the initial fire started after the network will fire pumps, and produces water hammer effect, stop-time will also have the effect of water hammer. Outlet pressure can be set on the pressure and can reduce the water hammer effect.
(6) diversion device settings are not correct
① suction pipe set water tank,
② suction pipe on bottom valve, high water tank fill water seepage. In fire protection engineering inspection we find that there are three kinds of not
(7) the pump's suction pipe diameter is small
Some designs use pipe diameter is small, pump flow can not reach the design values.
3¡ ¢ working stroke facilities
(1) pump with flow larger
4. pump adapter
(1) pump adapter and the fire hydrant or water in the distance is greater than 40m intake
(2) pump adapter low number of
(3) pump adapter does not partition settings
5. vacuum unit settings
(1) for fire protection design of dynamic pressure greater than 0.5Mpa is not set and vacuum unit
(2) decompression orifice diameter is small and some design such as an office building, selection pressure plate for B2-1F D/d = 65/14, start a fire pump, hydrodynamic pressure measured as 0.12Mpa, full 10m column page〈, detrimental to the fire.
6, fire hydrant button
(1) fire hydrant button functionality not Qi
Common errors include 4 types.
A, fire hydrant button cannot directly open pump, only through the linkage controller started the fire pump.
B, fire hydrant button starts no confirmation signal.
C, fire hydrant button does not display the alert, where parts of the body.
D, fire hydrant button through strong electric cycle pump 220V.
(2) temporary part of high pressure water supply system is not set in the fire box direct cycle pump button
7, fire water tank
(1) the roof with tank water pipe network without express fire
(2) combined with water tanks without fire-fighting water special measures
(3) fire water tank outlet check valve is not set.
8, the roof is not set check test fire hydrant
Automatic sprinkler system
1, fire water tank (see fire hydrant system)
2, the fire pump (see fire hydrant system)
3. voltage system
(1) voltage pump selection many engineering voltage pump flow on the high side.
(2) the location of the regulators pumps
Some designers high set voltage pump water tank, the nearest access sprinkler system at the top of the stack, this way, the problem is: when the nozzle heated after explosion, after pressure reducing valves, regulators pumps starts, can only be made after wet alarm valve pipe pressure rise and cannot open the disc, so the pressure switch is no signals start spraying pump.
4. pump adapter
(1) pump adapter settings
(2) pump adapter design number low and more.
5. vacuum unit setting some designers in the design of high-rise buildings fire sprinkler system had not been taken into account.
6, wet alarm valve
(1) set of wet alarm valve
Many projects in the locations of design alarm valve, consider not comprehensive.
(2) water supply control valve
Some project at design time in the water supply control valve is not set.
7. flow indicator
Flow indicator signal valve should be installed before, and the distance between the water flow indicator should not be less than the most works 300mm, have not been designed signal valve.
8. at the end of the test device
At the end of the test equipment including test valve, pressure gauge, drains, test tube diameter is not less than 25mm. Many projects at the end of the test equipment, pipe diameter < 25mm
9.System test pilot valve at the end of the linkage between open, pressure gauge readings shall be not less than 0.049MPa, many projects the most negative point water test, the pressure gauge reading is less than 0.049MPa. This is because the design-time does not take into account the most negative point of hydrodynamic pressure.
10, nozzle
Width greater than 1.2m of duct should be located under the VSMP nozzle. But most design units in the types of checks in the omission of this item. Designers in the design of nozzles, apart from considering meet these specifications, you should also consider the nozzle and high heat lamps and air duct outlet distance should not be too close together, so that the system is running after the nozzle is high-power thermal heating lamp emits misoperation caused by water; when the nozzle from the air too close to the sprinkler, water is sprayed out from air duct outlet out wind from normal watering range. Therefore designers in the design of nozzles should be with other professional designers meet together.
11 fire water tank
(1), (2), (3), (4) point to see the fire hydrant system
(5) Office of the fire water tank outlet check valve and tank set up at the bottom of the vertical distance is too small (usually less than 1m), the drop test, flow indicator not alarm.
12, pressure relief valves some works in the pump pressure relief valves has not been installed on the outlet pipe.
13, fixed pedestal and fixation
Designers on sprinkler system design and calculation of the load, and is based on the value of design with water standpipe dedicated load-bearing at the bottom of the pedestal, and should also be in conjunction with the architectural structure of professional design staff checking building structural components can withstand this pedestal delivered loads
14, casing and the wear line gap filler for select Design compact design-sprinkler system should be casing filling material selected. Select the glass fabric instead of asbestos for casing clearance fill material better.
15, hydraulic pressure switch alarm false alarms, and some of the false positives problem often is because the design reasons
(1) direct from the municipal water regulator because municipal water pressure fluctuation, but wet alarm valve is a valve that allows only the direction of mobile payment receipt. When the municipal water is low, the wet alarm valve is closed, then in municipal water pressure rise, when P1F1 > P2F2 wet alarm valve is open, causing a false positive.
(2) with constant voltage pump voltage. If regulators pumps up level, always keep the disc opening of small angle to supply water, that is, no "false positives". If the water rate, a start up water, disc and rushed to a large angle on the positives.
(3) set the pump system booster pump pressure causes false positives and regulated system of the same.
Foam extinguishing systems
1, foam mixture-dry pipe valve from the storage tank is near, and difficult to manipulate.
2. mixed liquid pipeline not set foam plugs
3. calculation of the number is the mixture of foam fire hydrant pipeline volume usage and taken into account
4. NET minimum service does not set the relief device
5, the highest parts of the road is not set to automatically discharge valve
Gas fire extinguishing system
1. fire fighting strength and quantity of extinguishing agent without accurate account book
2. on the compressive strength of the surrounding structure objects considered less
3, on protection zones delimited to consider less
For the three-tier set of protection zones, on the ceiling above and under the floor of the protection zone shall be separated by a space (ceiling, the following section) are strictly separated. For single nozzle arrangement: ceiling above parts separated specification has not been clearly established, look at the amount of extinguishing agent is designed taking into account the portion of space above the ceiling.
4. on the detector combination layout consider less
Probe for under floor due to the air conditioning air, after the detector should up the installation.
5, gas fire extinguishing systems for linkage problem
System design is not considered appropriate linkage control to close the openings, stop the fan and other functions.
6, exhaust gas fire places linked control
Gas fire extinguishing substance is in protected areas, fire extinguishing gas concentration released reaches a certain value after fight fire. Obviously, gas fire place in the fire, should be closed, in addition to close doors and Windows and ventilation, the exhaust facilities could not be opened. This is the place for general fire fighting. Modern architecture, there are many uses a glass curtain wall, fixed sash construction, some are for purify protection capabilities requirements closed architecture, some of which are rooms are set up mechanical smoke extraction facilities, some are set gas fire extinguishing installations. It is clear that appeared in the gas fire place settings, if smoke facilities does analysing requirements in the event of a fire when the control opens the smoke extraction facilities; to do so, from fire-fighting effectiveness is unreasonable. Therefore, the standard use of the site design to specific analysis.
Fireproofing system
1, used for evacuation channels on both sides of the fire shutter detector set is not set, and do not set the manual control button.
2, evacuation channel fire shutter does not use the following procedure to automatically control (design fire shutter General step down to the end)
(1) smoke detector actions the shutter down pitch (floor) surface 1.5 ~ 1.8m.
(2) thermal detectors actions after the shutter down to the end.
3. used for fireproofing fire shutter, fire detectors, shutter after the action has not declined.
4, the same fire zones used for fireproofing fire shutter, fire detectors action after worth mentioning shutter not group.
5. fire shutter control device does not have a dedicated power supply for fire. Fire shutter movements of feedback signal in indoor fire control cannot be displayed.
6-piece shutter open water protection.
Smoke control systems
1, mechanical smoke extraction system for exhaust gas volume is small, mechanical smoke system of positive pressure air is small.
2. high-rise construction does not have natural smoke conditions of smoke front staircase, combined with mechanical smoke Chamber is not set.
3, building height over a class public 50mTotal building and living more than 100m building stairwells and former Chamber with natural gas, but is not set mechanical smoke facilities.
4. set the smoke of basement does not set the air volume of not less than 50% of the exhaust air system.
5, basement mechanical smoke extraction system with exhaust vents and outlet switch cannot be linked.
6, exhaust vents, air supply valve open cannot start the linkage fan.
7, ventilation, air conditioning system with air duct through fire prevention Division, through the ventilation air conditioning room and important or fire risk large room partition wall and floor fire dampers are located.
8, kitchen, bathroom, toilet, and other vertical exhaust pipe, not take fire return measures, is not set on the branch pipe fire damper. This is a lot of designers often oversights.
9, anti exhaust fan remote can not stop, do not set manually direct control, the original and most engineering smoke fans will be able to launch remote control, remote stop could not be achieved.
10, the same floor for several air valve (smoke) of feedback signal should not be and get-threaded.
11, exhaust fan entrance and in the exhaust pipe is not set on the smoke fire dampers, smoke fire dampers and smoke exhaust fan interlocking, automatic shut down of smoke fire dampers. In addition to prevent the spread of pyrotechnic vertical and to not make Fireworks spread to exhaust fan is located (usually on the top floor), the entrance to the exhaust fan should be installed automatically closed smoke fire dampers.
12, supply outlet set location on the high side, where the exhaust port is set too low.
13, a high-rise building and building height exceeding 32m II high-rise construction construction area of more than 100m2 basement mechanical exhaust system is not set. 14, a high-rise building and building height exceeding 32m II high-rise buildings of no direct natural ventilation, and longer than the inner passages or 20m although direct natural ventilation, but longer than the inner passages not 60m set mechanical smoke extraction system.
15, positive pressure ventilation system air supply inlet set incorrectly. Exhaust outlet should be added after paragraph wind pipe, exhaust gas export by air supply system air supply inlet. To prevent accidents, there is a need for blower inlet set smoke detector and forced draft fan interlock, once smoke invade, blowers to immediately stop running.
16, high-rise buildings in annex part does not have natural smoke conditions before the Chamber (or room with front) is not appropriate to set the local mechanical smoke extraction facilities should be set locally positive pressure ventilation system.
17, smoke, anterior Chamber of positive pressure ventilation system should pressure blower set on suction tube valves and blower electric valve opening chain; the Atrium's smoke system should also be in the exhaust fan of the pipe is set on the check or set the normally closed exhaust valve (smoke fire dampers linkage is opened)
18, smoke staircases and combined with former rooms share the same pressurization system, leads to the combination of branch before room air duct pressure difference is not located on the automatic adjustment of the device.
19, against improper exhaust fan design position.
20, mechanical pressurization system of inlet check valve or is not set and the fan interlock electric valve.