【 Weak current College 】 common automatic sprinkler system problems---Power By 【 China power house network 】

Automatic sprinkler system by sprinkler, alarm valves, flow alarm equipment, pipes, water supply facilities, etc. The system is the most common water fire suppression systems, fire extinguishing, was very effective in the early days so has been very widely used. The authors in their day-to-day work, found some buildings of the sprinkler system design and construction in various problems, they not only affect the reliability of the system, but also affect the safe use of the building. The following will work in these issues, and we make some discussion. First, set on fire water tank 1. the automatic sprinkler system design code for the article: "5.0.1 system the most negative point the nozzle pressure should not be lower than 0.05Mpa". This requires the fire water tank and distance of the most negative point the nozzle is not less than the vertical height, some construction work 5m set booster measures is that they have failed to consider this requirement. You should set booster pump and regulators cans ensure supply for water pump starts before the initial pressure in the actual construction, some works will boost pump outlet as a fire water tank outlet, it is very wrong. This is because the set booster pump's main purpose is to fire the fire pump starts early, meet fire hydrants and fire sprinkler system pressure requirements, its water discharge on the fire hydrant system should not be greater than 5L/s, the automatic sprinkler system should not be greater than 1L/s, obviously much less than the regulatory requirements of the indoor fire water consumption, do not meet the initial fire-fighting water requirements. Therefore, on the roof of the booster pump set, in a outlet pipe booster pump bypass tube side set, water flow should not be less than the initial fire-fighting needs of water consumption. 2. the automatic sprinkler system design specifications "section 10.3.3 stipulates:" the fire water tank outlet check valve, and should be provided with alarm valve inlet before the pipe connections ". Some projects do not set the check, do not take into account this provision is to prevent backflow of water pump starts into the fire water tank. What is more, the fire water tank regulator pipeline without alarm valve is directly connected with water supply network. If the tank's water after alarm valve, alarm valve established after the hydraulic pressure switches, the warning does not occur in alarm, sprinkler systems, fire control pump does not start in a timely manner, result in a fire at the roof of the water after use, automatic sprinkler systems also did not reach the design purpose, directly affect the efficiency of fire suppression system. The correct connection should fire water tank outlet cited down a separate vertical tube connected to the alarm valve front. 3. the automatic sprinkler system design specifications "section 11.0.5 stipulates:" fire control rooms (spare) should be able to show the fire water tank water is in normal state feedback signal ". Many design and construction units in design and construction often ignore the fire water tank of water level alarm function. When the fire water tank inlet of ball aging damage, does not work, you may cause fire water tank storage capacity inadequate phenomenon, in the event of fire, fire-fighting water shortage, forfeiting the opportunity. When the control room can timely feedback when fire and water level in a timely manner to the tank water to ensure the fire water at all times in a normal state. Second, as regards eqnipment setting the automatic sprinkler system design specifications "section 6.5.1 stipulates:" each alarm valve group control of most disadvantageous nozzle, should be set eqnipment, other fire partitions, floors should be located with a diameter of 25 test water valve, eqnipment and test water valve should be easy, and should have adequate drainage capacity of drainage. "But some construction unit for ease of use, requirements for the construction unit will eqnipment settings in corridor, a room or toilet inside the ceiling, and not set in the most negative point, this would make it impossible to truly measure the most negative point of pressure value. Some construction unit do not use the eqnipment and DN25 ball valves instead. Ball valve (DN25) path is better than a 25mm, nominal size as 15mm (the actual aperture approximately 11mm) nozzle to much of the water after its opening is greater than a standard nozzle of displacement, it is clear that such a test water device cannot represent a nozzle opening effect, eqnipment open water flow must be equivalent to the fire zone 1 only within the nozzle flow, its test results to meet the test. Some eqnipment Department of drainage discharge is less than the pilot valve discharge valve discharge volume or even simply no drainage facilities that cannot be carried out on the water test.
III. alarm valve group design and install the sprinkler system design specifications "section 6.2.3 stipulates:" each alarm valve group control of nozzle should meet: wet system, preaction system should not be more than 800 only; dry system should not be more than 500 only. " If more than the above requirements, system maintenance, will cause your system to shut down part of too large; it also affects the reliability of the system. 2. the construction of automatic sprinkler systems and standardize on rule 5.3.1, 5.3.2, 5.3.3, 5.4.2 and 5.4.3 shall hydraulic alarm, pressure switch and retarder installation order definite requirements. Hydraulic alarm is hydraulic driving mechanical alarm signal, the pressure switch is hydropower signal conversion device, the delay is used to prevent sudden changes in water pressure caused alarm valve short open or partial due to alarm valve leakage into alarm temporarily pipeline flow, avoiding hold function and error reporting in device. During the installation should be aware of the correct sequence of components: hydraulic alarm in the alarm valve, retarder on alarm valve and hydraulic pressure switches between the alarm, the delay for hydraulic alarm entrance after the pipe must be installed vertically. Hydraulic pipe valve should be in the alarm normally open State, for the maintenance of alarm devices. Correct installation sequence should be: alarm valve--delay — pressure switch — hydraulic alarm. 3. the automatic sprinkler system design specifications "section 6.2.8 stipulates:" the water alarm pressure should not be .05mpa, and should meet the following requirements: someone should be located near a place of duty; and alarm valve connection of the pipe, the pipe diameter should be not greater than the total length of 20mm 20m. ”。 Hydraulic alarm installation position is not appropriate, the working pressure is too small. SomeSystem construction, hydraulic alarm installation location when you compare the subtle, not easy to hear people alert. The correct approach is to install the hydraulic alarm to regular people stay or go through, from fire control room or closer to the place of duty. But connection alarm valve and hydraulic alarm of pipe length should not exceed 20m, pipe diameter should be 20mm. Hydraulic pressure alarm work should not be .05mpa, also is the most negative point sprinkler system minimum working pressure (the automatic sprinkler system design specifications "section 5.0.1). 4. the automatic sprinkler system design specifications "section 6.2.6 stipulates:" 6.2.7 connection alarm valve control valve of imports and exports should be used in signal valve. When no signal valve, control valve should be set to lock valve position locks ". There are some system water supply control valve without obvious hoist flags. Existing practice usually uses the rising stem valve or the valve, the valve usually signals must be locked to open position. Automatic sprinkler system in the fire loss effects of one of the reasons is the control valve was closed, no water in the pipeline. 4. on the selection and installation of nozzle 1. the automatic sprinkler system design specifications "section 6.1.2 stipulates:" the closed system of nozzle, its nominal action temperature should be higher than the ambient temperature 30 ° c ". Hotels (hotel) kitchen, Entertainment Centre, locker room ambient temperature is high, it should no longer choose to 68 ° c nozzle, but you should choose the nominal temperature grade higher nozzle. 2. the automatic sprinkler system design specifications "section 6.1.2 stipulates the upright type, hanging-type nozzle and end wall of the maximum distance. While some projects in order to "dine" and "rounded", without expanding the nozzle and the side wall of the maximum distance. While this requirement is to make the nozzle spray jet wet wall surface does not flow leak spraying of distinctively and can spray wet a range of wall to prevent fire spread along the wall of the fuel. 3. the automatic sprinkler system design specifications "section 6.1.6 article illustrates the hospital ward building, public entertainment, the use of quick response sprinklers. In construction, some construction unit selection General nozzle instead of the quick response sprinklers. In such places, use the quick response sprinklers, fire early action, in the beginning stages of small fire, so that the fire started sprinkling of difficulty, you can achieve rapid fire, fire fighting, water maximizes casualties and fire damage and water Peter pollution caused economic losses.
4. the automatic sprinkler system construction and acceptance of the provisions of article 5.2.2 bar: "sprinkler installation shall be conducted on the sprinkler and dismounting, alterations to the nozzle is strictly forbidden any decorative coatings." Some engineering installation does not have to take measures to protect the nozzle, cement mortar, coatings, paints, etc. attached to the closed-head of liquid components, lowering the sensitivity of the nozzle, or even affect the nozzle opening. 5. with regard to the design and installation of pipeline 1. the automatic sprinkler system design specifications "section 8.0.5 stipulates:" the piping diameter hydraulic calculation shall be determined. Water distribution pipes for water distribution, should allow the entrance of the pressure equalization. Light hazard levels, risk levels in the water distribution in premises entrance pressure should not be greater than 0.40MPa ". Some design while able to guarantee that "each alarm valve set of water supply of the highest and lowest elevation difference nozzles, which should not be greater than 50m (the automatic sprinkler system design specifications" section 6.2.4) ", but did not take into account the risk-level", level sites in danger in the entrance of water distribution should not be greater than the pressure 0.40MPa ", does not guarantee that an alarm valve group distribution mains inlet pressure equalization, should be at the bottom of the settings within the system pressure orifice plate. 2. the automatic sprinkler system design code for the article: "8.0.3 galvanized pipe should be grooved fittings (hoop), threaded or flange connection. Before the adoption of internal alarm valve without corrosion protection of steel pipe, welding connection ". Some construction units on galvanized pipe welding connections too. Welded directly undermines the galvanized zinc plating, accelerate the pipeline corrosion. Alarm valve before such as corrosion protection of steel pipe inner wall not, welded connections. 3. the automatic sprinkler system design specifications "section 8.0.7 provides automatic sprinkler system and nozzle attached short risers, eqnipment connection pipe diameter shall not be less than 25mm. Otherwise will result in the pipe head loss or was debris blocked pipeline. 4. the automatic sprinkler system installation and acceptance of the provisions of article section 5.1.9: "pipe through the building of deformation seams, the measures to be taken against deformation," and "casing and piping of clearance should be non-combustible material filling dense". In construction, most of which are not in accordance with the provisions of the construction, ignored the buildings structure changes will make the network normally damaged factors; it also did not take into account that when the fire situation, due to the casing and wall or floor hasn't done between the river that is easy to be channeling smoke, channeling fire channel. VI. the fire pump 1. automatic sprinkler system design specifications "section 10.2.1 stipulates:" the system should be set independent of the pump. " The author in design review and acceptance, often found indoor hydrant system and automatic sprinkler system and fire pump. Due to the fire hydrant system and automatic sprinkler system time, and after the automatic sprinkler system for fire fighting quality will have a serious impact; if set combination system, fire hydrant piping must be before the alarm valve out. 2. the automatic sprinkler system design specifications "section 10.2.3 stipulates:" the system for pumps, regulators pumps, should adopt the way since irrigation-water absorption. In the near time the author in the acceptance process, find some room for aboveground fire pumps, fire water tank in the ground, the fire control pump of water-absorbent for inflated so it will be difficult to ensure that there is a fire, the fire pump starts in a timely manner. 3. the automatic sprinkler system design specifications "section 10.2.4 stipulates:" the fire pump should be set for a period of not less than 2 suction pipe "and" pump's suction pipe should be set control valve "and" outlet should be located control valves, check valves, pressure gauges and diameter of not less than the test water valve 65mm. " In audit, inspection, part of the project of the fire pump only sets a suction pipe, or just set up a water pipe,A project of the suction pipe is located on the control valve, water pipe without check valve, the water valve, there is no set ring of water pipelines, etc. The people at ease.