Why can’t fire pumps be started with active devices?
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\"Technical Code for Fire Water Supply and Fire Hydrant Systems\" (GB 50974-2014) 11.0.14 During a fire, the fire pump shall operate at power frequency; the pump should be started directly using power frequency； When the power is high, star-delta and autotransformer starting methods are recommended, while active device starting should be avoided. What is everyone’s understanding of this regulation?
According to GB-50116-2013 \"Code for Design of Automatic Fire Alarm Systems\" and the explanatory notes accompanying it, clause 3.1.8 stipulates that fire protection electrical control devices such as pump control cabinets and fan control cabinets shall not use variable-frequency starting methods. Explanation of the provision 3.1.8: To ensure the operational reliability of fire-fighting equipment such as fire pumps and smoke exhaust fans, fire electrical control devices such as pump control cabinets and fan control cabinets should not use variable-frequency starting methods.
Inverters are primarily used to control the speed of fans and water pumps driven by motors; closed-loop regulation is required. However, a decrease in speed affects the flow rate and head pressure. Fire pumps require a large flow rate and high head to meet the requirements. There’s no need for energy conservation – the building has already been burned down, so what’s the point of saving energy? It’s possible to switch to operating at mains frequency after startup, but the cost is too high. A soft starter can be used as a replacement. (It’s from Baidu, but after reading it I found it to make a lot of sense.)
Soft starting belongs to active starting, and active electrical components may experience an increased failure rate due to power supply issues; therefore, its use is not recommended. To ensure the effectiveness of fire pumps, they must be able to start up when needed; otherwise, they’re useless. Just as fire pump systems often use packing seals, any leaks that occur are simply that – leaks – but they do not affect the pump’s functionality.
One is that it adds intermediate steps, increasing the number of failure points. The simplest thing is the most direct, and it’s also the safest; that’s what it means