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For technicians engaged in water supply and drainage professional, "Technical Code for Fire-fighting Water Supply and Fire Hydrant System" GB50974-2014 should be an important criterion. For the most basic fire hydrant fire extinguishing system, the change of new regulations should be referred to as fire hydrant. System startup method.
1, the drawbacks of the original specification
The original code requires that the hydrant system of the temporary high-pressure water supply system must have a fire pumping button at the fire hydrant. In this case, the fire pump may have started. However, if the fire extinguishing system fails to fire in the future, the whole fire pipe network will not be put into operation. Waterless gun out of water to extinguish fire) The fire pump has been started, this will inevitably cause the pipe network pressure to increase sharply, resulting in a serious overpressure phenomenon, most likely to cause the pipe network burst, if there is a burst of fire, the entire fire hydrant system will collapse, the consequences are unimaginable .
Since any fire hydrant start pump button must start the fire main pump, put a group of main lines to put all fire hydrant buttons on the main line. This mode is independent of the fire alarm controller. After the button is accidentally lowered, special tools must be used to reset it. There are as many as hundreds of thousands of hydrant systems to find the button that needs to be reset to bring difficulties.
2. Control requirements for fire hydrant system with automatic fire alarm system set by the new specification
The latest fire code requires a temporary high-pressure fire hydrant system with an automatic fire alarm system. The fire hydrant pump-start button may not be provided but only an alarm button.
The first kind of interlocking control method, the flow switch of the high-level fire-fighting water tank outlet pipe or the low-pressure pressure switch signal of the water pump outlet serves as the trigger signal, and directly controls the starting hydrant pump;
In the second linkage control mode, the action signal of the fire hydrant button is used as the linkage trigger signal and is connected to the linkage controller of the fire control room, and the action signal of the fire hydrant button is sent to the fire linkage controller. After the action of the linkage control confirmation button is pressed The given control logic sends a linkage to open the fire hydrant pump signal. The fire pump action signal is fed back to the fire control room and displayed on the fire linkage controller.
3. Control requirements of the new code for fire hydrant systems without automatic fire alarm system
The number of fire hydrant is relatively small for the temporary high-pressure fire hydrant system without the automatic fire alarm system. The fire hydrant pump is still provided with the fire hydrant pump pump button. The on-site personnel opens the hydrant valve and presses the hydrant button. The hydrant button directly activates the hydrant pump and the hydrant pump. The action signal is displayed on the fire hydrant button by the fire linkage controller, which brings convenience to reset.
For the low pressure switch setting of the system, the initial value of the low pressure switch is the height difference between the elevation of the pressure switch and the highest water level of the high level fire water tank. The water level of the high level tank drops, and the static pressure felt by the low pressure pressure switch is reduced and converted into an electrical signal. , start the main fire pump; specifications given pressure switch electrical contact pressure gauges, pressure sensors, which makes the design more maneuverable.
4, the new specification of the flow switch, pressure switch settings
When the water level of the high water tank drops, the flow switch on the water outlet pipe of the water tank senses the flow of water and converts it into an electric signal. The main pump is started. The initial value of the flow switch should be zero. As for the flow rate, it will alarm. Personally think that it should be Select a suitable value between the leakage flow of the pipe network and 5L/S.
Does the sprinkler system with a high level fire water tank require a flow switch at the outlet pipe of the tank? Article 11.0.4 of the “New Regulations†states that: The fire pump should be provided with a pressure switch on the main pipe of the fire pump. High-level fire-fighting water tanks on the discharge pipe or alarm valve pressure switch light switch signal to automatically start the fire pump directly, literally should not be required, this study believes that because of sprinkler system in the layered or sub-area automatic On the horizontal main pipe of the sprinkler system, the water flow indicator is set on the floor or the partition, and both are coded into the program with the fire control center according to the address code.
Once a fire occurs in a certain zone or room, the sprinkler starts to spray water. When the system water passes through the indicator, the contact circuit in the indicator is turned on, and the zone (or layer) is controlled on the console. Somewhere there was a fire and an alarm was issued. At the same time, the main spray pump is turned on automatically for continuous water supply and fire extinguishing, so it is considered reasonable to no longer set the flow switch.
Conclusion
The introduction of "Technical Code for Fire-fighting Water Supply and Fire Hydrant System" and "Design Specification for Automatic Fire-alarm System" have made all types of fire-fighting equipment more timely and fire control more effective. From the point of view of the fire-fighting mode, the control of the system is more human, more operable, and more convenient to maintain. The setting of pressure switch and flow switch makes the design and operation of the system closer to the developed countries in the world, avoiding malfunctions and solving the problem of difficulty in resetting after misoperation. The forced detection of various water source and water level signals makes the fire water supply reliable. More sexual.
Analysis of the Change of Fire Pump Startup Mode in New Regulations
The change of the start method of the fire pump in the new regulation: "Technical specifications for fire water supply and fire hydrant system" has comprehensively stipulated the design, installation, construction, commissioning, acceptance and maintenance management of the fire water supply and fire hydrant system, not only with the The professional specifications of the regulations are also the basic and universal standards that govern various types of water fire extinguishing systems in terms of water source protection, water supply methods for fire-fighting water supply systems, and design parameters of fire-fighting water supply systems.