Which of the following is NOT a basic requirement for fire warning devices?

Local building codes are essential regulations that establish standards for construction and safety within a specific area. Fire warning devices must be installed in compliance with these codes to ensure effective functioning and alignment with safety standards. Each jurisdiction may have different requirements based on local conditions, historical data, and specific risks.

In contrast, the other options focus on universally recognized principles governing the installation of fire warning devices. These principles are designed to guarantee that the devices are not only functioning correctly but also suitable for their intended environments. Approval and listing for purpose ensures that the devices have been tested and certified to meet specific safety and operational standards. Installation according to manufacturer recommendations is crucial for the devices to operate as intended, maximizing their effectiveness in fire detection and alerting. Meeting the required minimum number of detectors is a fundamental aspect of ensuring comprehensive coverage and safety in a fire situation.

Therefore, although adherence to local building codes is critical, it is not categorized as a basic requirement like the others listed, which serve to ensure the effectiveness and reliability of fire warning systems.