This standard specifies the requirements for materials, construction, workmanship, and performance of both single-tone and dual-tone hand-operated sirens. These sirens are intended for use in fire-fighting, civil defense, and other emergency signaling applications in locations like factories, mines, and large establishments.
Specification - hand-operated sirens
Quick Reference Values
Minimum audibility range in still air (single tone)1.6 km
Minimum sound level at 30 m (single tone)114 dB
Fundamental frequency range400 to 800 Hz
Handle rotational speed for rated performance50 to 60 rpm
Endurance test duration25 hours
Practical Notes
When procuring, always insist on sirens bearing the ISI Certification Mark to ensure they meet the performance and durability standards.
The dual-tone siren provides a more distinct warbling sound which is more effective in cutting through background noise compared to the single-tone model.
Regularly test the siren for a few seconds to ensure the cranking mechanism is free and operational, especially in coastal or corrosive environments.