The LWF Blog
Facilities Management & Fire Safety – Gaseous Systems – Part 25September 13, 2017 11:02 am
In LWF’s blog series on fire safety for those who work in Facilities Management or who have a responsibility for fire safety in the workplace, we have been looking recently at the use of gaseous systems as a fire protection method. In Part 24, we talked about the different types of gaseous system and how and where they can be used. In Part 25, we’ll discuss the design codes involved before moving on to look at the typical components of such systems.
The majority of types of gaseous system are covered in BS EN 15004-1:2008, Fixed firefighting systems. Gas extinguishing systems. Design, installation and maintenance which covers each of the halocarbon and inert gases in use currently. CO2 systems, however, are dealt with separately in BS 5306-4:2001+A1:2012, Fire extinguishing installations and equipment on premises. Specification for carbon dioxide systems.
The components of a typical gaseous extinguishing system can be extensive and so it is essential that suitability for the building is established in every way before proceeding.
It is necessary to have a facility where the gaseous agent can be stored, as well as an automatic fire detection system which will pinpoint the area in which a fire ignites so that the gas agent can be released. In addition, it is important to have manual release controls in case they are required.
The installation of a gaseous extinguishing system will involve a network of pipes and discharge nozzles in order to deliver the agent at any point throughout the building or area of installation. It is also necessary to have the ability to switch the system between automatic and manual modes and to have a method of total isolation of the system.
The gas storage facility itself will contain a central bank of storage cylinders which are placed outside the protected area of the installation, although in some circumstances it is possible to have the cylinders distributed throughout the protected area.
In the case of a CO2 installation, the gas may be stored in a refrigerated tank and at a lower pressure.
It may be necessary to have a separate and self-contained automatic fire detection system and further guidance on this can be gained from BS 7273-1:2006, Code of practice for the operation of fire protection measures. Electrical actuation of gaseous total flooding extinguishing systems.
Particularly in the case of smaller CO2 systems, it may be the case that a simple mechanical means of detection and deployment are all that is necessary. For example, the inclusion of one or more fusible links in the protected area would be attached to a wire under tension. When the heat from a fire melts the fusible link, the wire is released and a weight falls, activating the release mechanism for the gas.
BS 7273-2:1992, Code of practice for the operation of fire protection measures. Mechanical actuation of gaseous total flooding and local application extinguishing systems, gives details on the use of such systems.
In Part 26 of this series, we will look at electrically actuated systems and wet chemical systems. In the meantime, if you have any queries about your own facilities or wish to discuss this blog series, please contact Peter Gyere in the first instance on 0208 668 8663.
Lawrence Webster Forrest is a fire engineering consultancy based in Surrey with over 25 years’ experience, which provides a wide range of consultancy services to professionals involved in the design, development and construction and operation of buildings.