Fire water extinguishing system is an important means of fire extinguishing. Fire water extinguishing system is the most common fire extinguishing system in civil buildings and industrial plants. It is in a very important way in fire engineering. Therefore, the maintenance of firefighting water systems is of great significance to the fire safety of buildings. How to ensure the integrity and normal operation of water firefighting systems is an important task for maintenance. Because the best time to extinguish a fire is in the early stages of a fire, maintenance is to ensure that the water extinguishing system is always in normal working condition.
2 Classification of sprinkler systems
There are many types of sprinkler systems, as follows:
(1) According to the fire extinguishing function, it can be divided into automatic water spray, water spray, water curtain protection (separation), and foam fire extinguishing.
(2) According to the alarm valve, it can be divided into wet system, dry system, pre-action system and rain system.
Wet system: suitable for places where the ambient temperature is not lower than 4 ℃ and not higher than 70 ℃.
Dry system: suitable for places where the ambient temperature is lower than 4 ℃, or higher than 70 ℃.
Pre-action system: It is suitable for places where water leakage from the pipeline is strictly prohibited, and accidental spraying of the system is strictly prohibited, or to replace the dry system.
Rain shower system: It is suitable for the place where the fire spreads quickly and the closed sprinkler is opened, which can not effectively cover the fire area in time; or the clearance height exceeds the height of the closed sprinkler.
3 Common problems and countermeasures of sprinkler systems
3.1 Improper installation of water pump adapter
In some buildings with large-area glass curtain walls, the water pump adapter is placed on the solid wall under the glass curtain wall. Under fire conditions, falling glass will threaten the safety of the water pump adapter. From the perspective of use safety, the water pump adapter installed on the wall should avoid the glass curtain wall.
3.2 Water supply to sprinkler system cannot be guaranteed
Some buildings use landscape ponds with aquatic plants and even fish and shrimp as water sources for sprinkler systems. However, there are no corresponding filtering and water purification facilities at the pump suction port, and it is easy to inhale water with impurities and block it. Wet alarm valve clapper or the hole of the hydraulic bell in the ring groove of the seat ring affects the action of the hydraulic bell and pressure switch, generates false alarms or no alarm, or blocks the sprinkler head, causing the system to fail.
3.3 Inadvertent protection of nozzles during construction
(1) After the closed sprinkler was installed and installed, no corresponding protective measures were taken, so that cement mortar, paint, paint, etc. adhered to the temperature sensitive element of the closed sprinkler, which caused the closed sprinkler to fail to sense the temperature correctly and prolonged the time of fire fighting;
(2) During the decoration of the suspended ceiling, due to the poor construction quality, the suspended ceiling collapsed, causing the sprinkler head to retract into the suspended ceiling, which affected the sprinkler sprinkler fire extinguishing effect.
3.4 The working environment of the pump room of the sprinkler system is harsh
(1) The underground pump room is extremely humid, which causes great damage to the pump and the pump control cabinet in the same room. The humidity also causes the pump motor to fail multiple times.
(2) Poor drainage of the underground pump room can easily cause flooding of the pump room and cause accidents.
3.5 System alarm valve setting
The roof water tank provides the fire-fighting water for the first ten minutes of the sprinkler system. If the water flow from the roof water tank does not pass through the system's alarm valve, the pressure switch and hydraulic alarm bell set behind the alarm valve can not give an alarm, and the automatic sprinkler pump It cannot be started in time. Even in the event of a fire, after the water in the roof tank is used up, the sprinkler system has no water available, which directly affects the fire extinguishing efficiency of the system. The correct connection method is to connect the vertical pipe under the roof water tank to the front of the alarm valve, that is, the water in the roof water tank must enter the alarm valve before spraying water through the sprinkler.
3.6 Stable pump flow setting
According to the requirements of the code, the supplementary water supply of the stabilizing pump of the sprinkler system should not exceed 1L / s, but the flow rate of the stabilizing pump selected for the sprinkler system of some buildings is much higher than this standard. When the valve flap of the wet alarm valve is opened in a small angle range (not exceeding 30 °), the alarm channel of the alarm valve has not been opened, and it will not cause the automatic sprinkler pump to start. If the water supply flow of the pressure-stabilizing pump is too large, the valve flap of the alarm valve will open at a large angle, which will cause the pressure switch and hydraulic alarm bell to act and start the automatic sprinkler pump. Therefore, a low-flow regulator pump should be selected.
3.7 Nozzle arrangement
Some large space buildings are divided into many small rooms due to secondary decoration or changes in use functions. The nozzles originally designed for large spaces have not been adjusted due to space separation. There are no nozzles in some divided areas, or there are nozzles in the same location Improper, as it should have been arranged in the middle, it has become a layout next to the partition wall, which has resulted in a blind zone protected by the sprinkler head. In the event of a fire accident, the consequences are unthinkable.