【Common Issues in Haichuan Pipeline Design】Why does fire water need to be filtered?

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\"Technical Code for Fire Water Supply and Fire Hydrant Systems GB50974-2014\": \"5.1.15 A pipe filter may be installed on the suction pipe of the fire pump; the flow area of the pipe filter should be more than 4 times that of the pipe itself, and its pore size should not be less than 3 mm.\" \"Code for Construction and Acceptance of Automatic Sprinkler Systems GB50261-2017\": \"4.2.3 The installation of suction pipes and their accessories shall meet the following requirements: 1 Filters should be installed on the suction pipes, and they shall be placed behind the control valves.\" The explanatory text for this clause states that \"the proper installation of the suction pipe of the fire pump is the fundamental guarantee for the normal operation of the fire pump.\" A filter should be installed on the suction pipe to prevent debris from entering the water pump and affecting the system’s water supply. At the same time, the filter should be easy to clean to ensure proper water supply to the fire pump. Due to the small mesh size of the filter installed in the water suction pipe, it needs to be cleaned frequently; however, this is not properly carried out in practical engineering applications, which can easily lead to blockages or a significant reduction in the pipe’s water flow capacity. In engineering applications, filters are installed at the water intake of pumps; as a result, ordinary debris does not enter the suction pipe. Therefore, it is not mandatory to install filters on the suction pipes. However, in systems equipped with filters, these filters should be cleaned regularly to ensure the proper flow capacity of the piping system. For example, according to the \"Technical Code for Fire Fighting Water Supply and Fire Hydrant Systems GB50974-2014\", \"4.1.6 When rainwater tanks, reclaimed water tanks, water features, and swimming pools are to be used as fire fighting water sources, technical measures must be in place to ensure that the water volume and quality required by the fire fighting water supply system are met under all circumstances.\" Regarding this point, what many people think of is whether there is water available and whether it can be used. In fact, there is another aspect to consider: even if there is water, it’s important to take into account that these water sources may not be completely clean; they might contain leaves, hair, and other substances that could cause blockages in the pipes. If such things happen, reliability is obviously not guaranteed. This requirement is expressed very clearly in another clause. “4.4.4 When natural water sources are used as outdoor fire water supplies, technical measures shall be taken to prevent substances such as ice, floating objects, and suspended matter from clogging the fire pumps, and measures shall also be implemented to ensure safe water extraction. ”The provisions state: \"4.4.4 This clause is a mandatory one and must be strictly enforced.\" Since natural water sources may contain ice, floating objects, suspended particles, and other substances that can clog the water intake, it is necessary to install grids or filters and other measures to ensure the reliability of the water intake. At the same time, the effects on the water intake of fire pumps resulting from factors such as head loss that may arise from the measures taken should be considered. ” \"Technical Code for Fire Water Supply and Fire Hydrant Systems GB50974-2014\": \"4.4.6 The location and facilities of the water intake for fire trucks using natural water sources shall comply with the provisions regarding surface water intakes in the current **standard, Code for Design of Outdoor Water Supply GB 50013. A grille should be installed at the water intake; the spacing between the grid bars should not be less than 50 mm, or filter tubes may also be used.\" To ensure the reliability of filters, the \"Technical Code for Fire Water Supply and Fire Hydrant Systems GB50974-2014\" also stipulates that \"14.0.9 The system filters shall be cleaned of debris at least once a year, and it shall be checked to determine whether they are in good condition; any blockages or damages should be repaired promptly.\"