The LWF Blog

Fire Engineering for Healthcare Premises – Fire Detection & Suppression – Part 48

August 16, 2021 12:02 pm

In LWF’s blog series for healthcare professionals, our aim is to give information on best practice of fire safety in hospitals and other healthcare premises. In part 47 of Fire Engineering for Healthcare Premises, LWF discussed fire detection and suppression systems and how they work. In part 48, we will explore fire suppression systems, such as gaseous flooding systems like Halon, and how they work to extinguish fire in different circumstances.

A Halon fire suppression system is designed to flood a compartment with a gas that has flame extinguishing properties. Halon, while extremely effective and not toxic to people, was considered damaging to the ozone and so was production was banned under the Montreal Protocol. It is still used in very few circumstances, where no other alternative is possible and where the halon itself is either purchased from existing stocks held by some companies or from recycling the gas from systems no longer in use. Historically, Halon has been utilised on the Eurotunnel, aircraft fire extinguishers and some military applications.

Other gaseous flooding systems include carbon dioxide and inert gases which work by diluting the available oxygen. When a fire can no longer get sufficient oxygen to burn, it is unable to continue to grow and will ultimately extinguish.

Many gaseous flooding systems are only suitable for areas where personnel are not allowed or have already been safely evacuated. The dilution of oxygen, for example, would make an area unsuitable for human habitation until the gas (and smoke) had been cleared and the oxygen levels returned to normal.

Replacements for Halon are being developed. The idea is that they will operate in the same way – safe for use in enclosed areas where people cannot evacuate, but that they will not be damaging to the ozone. Some Halon replacements will not be suitable for use around people, as they generate hydrogen fluoride gas, which is a highly corrosive acid gas. 3M™ Novec™ 1230 and FM-200™ are two existing replacements which do not harm people or leave residue.

Any gaseous flooding system must be appropriate for the environment in which it will be used.

In Part 49 of LWF’s blog series, LWF will talk about smoke detection and how smoke detectors work. In the meantime, if you have any questions about this blog, or wish to discuss your own project with one of our fire engineers, please contact us.

Lawrence Webster Forrest has been working with their clients for over 25 years to produce innovative and exciting building projects. If you would like further information on how LWF and fire strategies could assist you, please contact LWF on freephone 0800 410 1130.

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.