When procuring fire alarm systems, technical reliability is paramount. You must verify the UL 864 standard for Control Units and Accessories and UL 268 for Smoke Detectors. Key specifications include dual-loop addressable capabilities for large-scale installations, backup battery standby time (typically 24-72 hours), and decibel levels (minimum 75dBA at 10 feet) to ensure compliance with life safety codes. Additionally, prioritize sensors with photoelectric technology to reduce false alarms from cooking or steam.