Estimate the number of sounders required for adequate coverage
BS 5839-1 Requirements:
Sleeping Areas: 75 dB(A) at the bedhead
General Areas: 65 dB(A) throughout or 5 dB(A) above ambient noise
Sound Level Decay: ~6 dB per doubling of distance (inverse square law)
Barriers: Closed doors reduce sound by 15-30 dB
m²
dB(A)
m
Sounders Required
0
⚠️ Important Limitations
This calculator provides simplified estimates only and does not replace professional acoustic design or fire alarm system design.
Actual requirements depend on:
System integration - Must coordinate with detection zones and control panel
Always engage a qualified fire alarm system designer for accurate specification and to ensure full regulatory compliance.
📚 Further Reading (UK Standards & Guidance)
BS 5839-1:2017+A2:2024 - Fire detection and fire alarm systems for buildings - Code of practice for design, installation, commissioning and maintenance of systems in non-domestic premises
BS EN 54-3:2001+A1:2002 - Fire detection and fire alarm systems. Fire alarm devices. Sounders
FIA Code of Practice for Fire Alarm System Design - Fire Industry Association practical guidance
Apollo Fire Detectors - BS 5839-1 Pocket Guide - Practical installation guidance
Apollo Pocket Guide (PDF)
⚠️ Disclaimer: This calculator is provided as a guidance tool only. Always verify calculations independently and consult current BS 5839 and BS EN 54 standards. Professional fire alarm system design should be undertaken by qualified fire alarm engineers. Actual sound propagation depends on many environmental factors.