Comprehensive trade guide: multi-sensor fire alarms & thermoptek technology

The fire safety landscape in the UK has evolved greatly in recent years. The introduction of the Smoke and Carbon Monoxide Alarm (England) Regulations 2022 has resulted in more stringent standards that landlords and installers must abide by. In addition, the advancement of fire safety technology is seeing increased demand from customers for more sophisticated solutions.

For trade professionals, meeting compliance requirements while delivering the best protection for clients is paramount. That’s where multi-sensor fire alarms come in — offering enhanced detection, reduced false alarms, and future-proof compliance.

This guide explores what multi-sensor fire alarms are, the BS 5839-6 and EN 54-29 standards, leading product choices, and installation best practices, helping you make informed recommendations that drive both safety and customer satisfaction.

What are multi-sensor fire alarms?

Multi-sensor fire alarms combine two or more different fire detection technologies within a single unit, most often optical smoke and heat sensors. Some advanced models also include a carbon monoxide (CO) sensor.

As different sensors detect different types of smoke and heat, and therefore different types of risk, combining more than one sensor in a single unit can help to better differentiate between a real fire and false alarms.

Reduction in false alarms is a key advantage of multi-sensor alarms. In the UK, false alarms continue to rise, with a large majority coming from apparatuses. Of the 254,041 false alarms attended by Fire and Rescue Services in the year ending September 2024, 183,115 were due to apparatus. This highlights the critical need for reliable and efficient fire alarm systems.

Other benefits of multi-sensor alarms include better detection of a wider range of fires including slow smouldering and fast-flaming thanks to the multiple data points it uses from the different sensors. These alarms are also increasingly recommended for optimal protection and compliance.

Which alarm is best for me?

When specifying multi-sensor alarms for trade projects, choosing the right model ensures you meet compliance while delivering the best long-term value.

Below are FireAngel’s leading trade-ready multi-sensor alarms, all featuring patented Thermoptek technology — combining optical smoke sensing with thermal enhancement for faster, smarter fire detection.

Meet our Range

1. FireAngel FS2126-T 10 Year Multi-Sensor Smoke Alarm
   A battery-powered, sealed-unit multi-sensor alarm using Thermoptek technology. Designed for rapid detection of all fire types, it’s suitable for hallways, landings, living rooms, dining rooms, and bedrooms.
2. FireAngel Pro Connected FP2620W2-R
   A smart, battery-powered multi-sensor alarm with Thermoptek technology. Offers wireless interlinking with other Pro Connected alarms (smoke, heat, CO), app integration for real-time alerts, and a 10-year sealed battery. Ideal for larger properties or where remote monitoring is required.
3. FireAngel ST-622Q / ST-622T 10 Year Thermoptek Smoke Alarm
   A popular, stand-alone multi-sensor alarm with a 10-year sealed battery. Features Thermoptek technology for fast response to both fast-flaming and slow-smouldering fires, smart silence for nuisance alarms, and is “toast proof” for use near kitchens.
4. FireAngel ST-750T 10 Year Thermoptek Smoke Alarm
   Another advanced multi-sensor alarm with a 10-year sealed battery, smart silence, and reduced nuisance alarms. Designed to meet UK Fire & Rescue Service specifications.
5. FireAngel SM-SN-1 Mains Powered Thermoptek Multi-Sensor Smoke Alarm
   A 230V mains-powered multi-sensor alarm with a sealed-for-life battery backup. Hard-wired interlinking capability, low power consumption, and suitable for new builds or major refurbishments.

For even more advanced protection, explore interlinked alarms. Interlinked smoke, heat, and carbon monoxide (CO) alarms offer unparalleled safety by ensuring that all alarms in a property sound simultaneously when one detects danger. They work as a network by transmitting signals between devices to ensure synchronised alerts. These are particularly beneficial for vulnerable residents.

Multi-sensor alarms are recognised as an enhancement within British Standards BS 58396, meaning they go above and beyond the minimum requirements and are an excellent choice for installers for any property.

To discover our full product range, as recommended by experts, click here.

Why trade installers should choose multi-sensor alarms

1. Simplified installations: one unit covers both smoke and heat detection, reducing the number of devices needed in a property.
2. Lower false alarm rates: Thermoptek’s dust compensation and dual-sensor verification minimise nuisance triggers from cooking smoke or steam.
3. Enhanced compliance and future-proofing: BS 5839-6 recognises multi-sensor alarms as an enhancement. Specifying them now positions housing stock for future regulatory updates.
4. Improved tenant satisfaction: fewer false alarms mean fewer call-outs and happier residents, saving both time and maintenance costs.

FAQs

Q: Where should a multi-sensor fire alarm be installed?
A: Install in hallways, landings, and living spaces per BS 5839-6 and manufacturer instructions.

Q: Do multi-sensor alarms cause fewer false alarms?
A: Yes. By combining heat and optical sensors, they can verify smoke type before triggering, reducing false alarms.

Q: What’s the difference between mains powered and battery multi-sensor smoke alarms?
A: Mains powered multi-sensor detectors meet Grade D1/D2 requirements and offer backup batteries; battery multi-sensor smoke alarms are easier to install and ideal for retrofits.

Q: Can multi-sensor alarms be interlinked?
A: Many models offer hard-wired or wireless interlinking — essential for larger properties or vulnerable residents.

Q: How do I confirm BS 5839-6 compliance?
A: Check manufacturer datasheets and ensure installation matches the grade and category specified in BS 5839-6:2019.