STI STI-1100NR Stopper II Horn Flush Mount Fire Alarm Cover

Overview

The STI-1100NR is a flush-mount protective cover retrofit for manual fire alarm break-glass call points that addresses false alarms without blocking legitimate emergency activation. The clear polycarbonate housing and frame mount directly over existing call points via four fasteners. When the cover lifts to access the glass, an integral 95 dB sounder activates immediately, drawing attention to the area and deterring accidental or malicious triggers. The 24VDC powered variant makes it suitable for schools, hospitals, nursing homes, and public buildings where call-point access must remain available but false activation is a recurring problem. This no-label version ships blank, supporting custom labeling or label-free operation.

Compatibility

The STI-1100NR retrofits over standard manual fire alarm break-glass call points used in North American commercial and institutional fire alarm systems. It accommodates both flush and surface-mounted call point installations, provided your existing unit falls within the standard manual call point envelope. Confirm mounting geometry with your call point manufacturer or security integrator before ordering — non-standard mounting hardware or oversized housings may require a different cover variant. The sounder is powered independently via 24VDC, so it does not draw power from the call point circuit itself.

Installation Notes

Installation requires four fasteners (not supplied) and takes 10–15 minutes per unit. The polycarbonate housing is rated for operation between −40°C and 49°C, making it suitable for unheated/uncooled spaces such as vestibules and loading docks. Wire the 24VDC sounder to a dedicated security power loop or shared building power with sufficient capacity — current draw is minimal. No special tools beyond a standard screwdriver are required. Polycarbonate is warranted against breakage for three years under normal use; electromechanical components carry a one-year manufacturer warranty.