Fire Safety, Maintenance

Types of Smoke Alarms – Multi-Sensor, Optical, Ionisation

Multi-Sensor Smoke Alarms – Recommended Technology

FireAngel Specification smoke alarms use Thermoptek Multi-Sensor technology, which provides the ultimate protection at an affordable price. Thermoptek technology combines optical and heat detection technologies to increase the sensitivity of the alarm for a faster response. This enables FireAngel alarms to monitor two different by-products of fire simultaneously, and hence respond to all types of fire – a vast improvement over traditional single sensor alarms. These products are also less prone to false alarms associated with the ionisation and the optical type alarms.

Optical Alarms

Optical alarms are effective at detecting larger particles of smoke from slow burning, ‘smouldering’ fires, e.g. cigarettes on furniture or bedding. These can be placed near kitchens and in circulation spaces, but not too close to poorly ventilated bathrooms as they are liable to false alarm when exposed to steam.

Show FireAngel alarm with optical sensing technology – SW1-PF-T / SB1-T

Ionisation Alarms

Ionisation type smoke alarms are more effective at detecting small particles of smoke produced by fast, flaming fires which consume combustible materials rapidly and spread fire quickly, e.g. ignited paper or curtains. Ionisation alarms should not be placed near kitchens/ hallways as they are more liable to false alarm due to cooking fumes.

In 2018 FireAngel made the decision to support UK Fire and Rescue services and we moved away from ionisation alarms due to storage and disposal issues and risk of false alarms.

The problems with ionisation technology

Whilst perfectly safe to residents, ionisation fire alarms are banned in several countries as they contain small quantities of radioactive material (Americium 241) meaning there are storage and disposal issues. It is therefore expected that the UK will soon follow suit.

Ionisation alarms are also more prone to false alarms in domestic premises compared to optical and multi-sensor alarms available. Of these, optical alarms are marginally less sensitive to fast flaming flames, so the Fire and Rescue Service advocate installing multi-sensor alarms around the home. These provide residents with ultimate fire protection as they work to detect two different signs of fire (heat and smoke), and so have a faster response time to all types of fires.

As outlined by Mark Hazelton, National Fire Chiefs Council Lead:

 “We’ve moved away from ionisation detectors (normally the cheapest detectors sold). Whilst these alarms are still sensitive to smoke and will detect fires, they can be over-sensitive, causing spurious (false) alarms when toast is burnt”

The movement away from ionisation fire detectors

Supporting the Fire and Rescue Service’s decision to avoid fitting ionisation technology, FireAngel has made the decision to phase out ionisation sensing technology this year.

In fact, here at FireAngel we are launching a new FireAngel range of mains battery backup powered alarms in April, which will offer the benefits of optical sensing technology for the price of ionisation.