How many flow switches can be put on one fire alarm panel zone?
Flow switches are a contact device and don’t require power from the fire alarm system to operate like system smoke detectors do, for instance. Technically you’re limited by the length of wire run and the maximum voltage drop allowed by the manufacturer to the end-of-line resistor (see our FAQ #24), but in practice, most fire departments (and the local authority) like to see each flow switch on its own zone. When a water-flow alarm is initiated, a number of Provincial Building Codes stipulate that a separate signal from the normal “common fire alarm” is generated to the Central Station. This alerts the responding authority to the fact that a sprinkler head is discharging (which usually means an actual fire has tripped it). In a multiple story building (or a large industrial/commercial complex) having specific zones identified on a readily accessible alarm annunicator will help reduce the time it takes for the fire fighters to pinpoint the fire’s location and intercede to limit the resul
