What is the maximum number of multi-station devices that can be on an unsupervised loop?

The correct answer is based on the specifications and limitations set by the National Fire Protection Association (NFPA) and relevant fire safety standards. In a fire alarm system, multi-station devices, such as interconnected smoke alarms, are designed to communicate with one another to ensure early warning during an emergency.

The maximum number of multi-station devices that can be installed on an unsupervised loop is generally limited due to potential concerns regarding response time and signal integrity. In most cases, the industry standard sets this limit at 18 devices on a single unsupervised circuit. This guideline helps to ensure that the system remains effective and that alarms can be reliably triggered without overwhelming the circuit.

Understanding these limitations is crucial for ensuring compliance with fire safety regulations and for maintaining the reliability of alarm systems in practical applications.