Smoke Detection in High Ceiling Applications Using ASD

For many years high ceiling applications have been considered very challenging for reliable operation of automatic point smoke detection. Many national design and installation codes, including BS5839 Part 1, specify limitations on ceiling heights that are protected by a particular product technology.

As a result designers and installers tend to use detection technologies such as beam detection and aspirating smoke detection (ASD) where smoke measurements over an area, rather than from a single location, are determined. Independent tests have shown that ASD has a far higher sensitivity to smoke than point detector technology, resulting in a superior ability to detect smoke that is diluted or distributed as it rises to higher levels.

In 2008 BRE (Building Research Establishment) Global, whose remit is to work with manufacturers to ensure that fire, security, environmental and other products and services provide quality of performance and protection, completed a three-part research project (together with the Fire Industry Association) to review the use of beam detection and ASD technology in high ceiling applications.

The positive tests that came out of this process resulted in the FIA Code of Practice for ASD being revised. This was largely due to the high sensitivity ASD needs to support multiple holes and the cumulative effects that result from smoke entering a number of sampling holes.

The research confirmed that ceiling height limits for aspirating smoke detection should be based on those for beam detection (which is used at heights of 25m or 40m for property protection) on the provision that Fire Rescue Services can attend within 5 minutes. Other independent tests have confirmed that a Class C aspirating smoke detection system with 20 sampling holes at a height of 43m can detect relatively small fires (<500kW). For detailed information and recommendations, refer to the FIA code of practice.

Suitable Aspirating Smoke Detectors for High Ceiling Applications

Many of the ASD systems Eurofyre supply and support operate at Class A, B & C sensitivity depending on the amount of designed sampling holes, an example of which is the EF-FT1.

The EF-FT1 is a 4-pipe detector that can cover a single zone of up to 2000m². It is classified as a very early warning smoke detector and has the ability to reliably detect fire at an early stage with an alarm sensitivity range of 0.001% to 20% obscuration/m (0.0003% to 6.10% obscuration/ft).

Key Features

  • EN54-20 approved
  • 4-pipe air-sampling
  • Single zone
  • Area coverage up to 2000m²
  • 0.001% to 20% obscuration/m
  • 4 alarms – Alert, Action, Fire 1, Fire 2
  • 4 x 100m (max) sampling pipes
  • 5 relay outputs as standard
  • Optional internal power supply and batteries

For more information please visit the aspirating smoke detection section on our website, alternatively, please do not hesitate to get in touch either by email to [email protected], by telephone on 01329 835 024 or through our online enquiry form.