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NPFA 72 and the 100-Second Delay for Sprinkler Waterflow
NFPA 72, the National Fire Alarm and Signaling Code®, covers requirements related to waterflow initiating devices in section 17.13. The main reason for the delay in occupant notification from sprinklered waterflow is to reduce the number of nuisance alarms that can occur from pressure surges in the water supply system. The delay allows time for waterflow from the sprinkler to be detected at the riser and ensures that the waterflow is a result of sprinkler flow. Reducing the number of nuisance alarms is important because the more they occur, the more that occupants ignore them.
NFPA 72 100-Second Delay, Two-Part Requirements
NFPA 72 17.13.2 of the 2022 edition covers the first requirement related to waterflow initiating devices and requires the device to activate within 90 seconds of a flow occurring that is equal to or greater than flow from a single sprinkler of the smallest size. The flow switch itself allows for the creation of a delay in waterflow or the delay can also be initiated by using a retarding device.
NFPA 72 section 10.11.1 contains the second part of this delay which requires the activation of alarm notification on the premises occurs within 10 seconds after the initiating device activation. This ensures that notification devices occur quickly after a fire has been detected. Between these two requirements, a total delay of 100 seconds is permitted between the initial sprinkler waterflow and activation of notification in the building.
Buildings designed with this 100-second delay require a detailed response plan and approval by the authority having jurisdiction (AHJ). This time delay ensures that notification of a fire is accurate, reduces nuisance alarms, and helps to make sure that sprinklered suppression systems and commercial fire alarms function as effectively as possible.
HRSS Offers Commercial Fire Alarm System Design and Equipment
High Rise Security Systems, HRSS, is recognized as a leading commercial fire alarm and life safety system provider in the Chicagoland area, offering fire alarm system design and quality, UL listed equipment. Our fire safety specialists possess deep technical knowledge of all National Fire Protection Association, NFPA, standards as well as all local, state, and federal building and safety codes.
We help our customers to design the best commercial fire alarm system, including detection devices, initiating devices, suppression systems, including sprinkler waterflow switches, and notification devices.
HRSS ensures that your commercial building’s fire alarm and life safety system is compliant with all fire safety codes and standards and designed to meet your specific business needs. We partner with our customers to determine the best notification devices for your type and design of the building and go above and beyond code compliance. Contact us to make sure your commercial property is safe and your occupants are protected in any type of building.