The LWF Blog

Fire Safety for Facilities Management Personnel – Fire Detection & Fire Alarms – Part 189

February 20, 2023 12:17 pm

Lawrence Webster Forrest (LWF) is a specialist fire engineering and fire risk management consultancy whose aim is to give information on best practice in fire safety for facilities management personnel through this blog series. In part 188, LWF discussed smoke detectors. In part 189, we will continue to look at aspirating smoke detection systems and consider their appropriate usage.

Aspirating smoke detection systems are frequently seen protecting computer, communications and sensitive electronic equipment rooms in buildings. They are often used to monitor return air as it is returned to air conditioning units. This method means that very small amounts of particulate matter, such as that produced by even a very small smouldering incident, can be detected by this type of smoke detection system. The combustion products are carried by the return air to the sampling points in the pipework of the aspirating system.

Such is the sensitivity of these aspirating smoke detection systems that it is not uncommon for them to detect the burning out of electrical components in equipment cabinets and trigger an alarm. An inspection of the room wouldn’t show any visible trace of smoke.

Aspirating systems may also be used in atriums, where vertical runs of pipework sample smoke from different levels, at any of which stratification might occur.

An aspirating system may be installed in a stately home or listed buildings where the nature of the installation and it being virtually invisible is of the utmost importance. The pipework can be installed above the ceiling and small-bore capillary tubes passed through small holes drilled into the ceiling.

Aspirating systems may be used where access to point smoke detectors for maintenance would be difficult. For example, installation at high levels within an atrium space or a high-level ceiling void.

The additional advantage to using an aspirating smoke detection system in an area with a high ceiling is the sensitivity of the system allows it to detect smoke that is diluted or dispersed as it rises. At heights of as much as 40 metres, a relatively small fire can be detected by an aspirating smoke detection system, whereas a point smoke detection based system would require the fire to grow to a larger size before it was detected.

In part 190 of this series, LWF begin to look at flame detectors, what types are available and how they work. In the meantime, if you have any queries about your own facilities or wish to discuss this blog series, please contact LWF on freephone 0800 410 1130.


Lawrence Webster Forrest is a fire engineering consultancy based in Surrey with over 35 years’ experience, which provides a wide range of consultancy services to professionals involved in the design, development and construction and operation of buildings.


While care has been taken to ensure that information contained in LWF’s publications is true and correct at the time of publication, changes in circumstances after the time of publication may impact on the accuracy of this information.

Share this post