Due to the size and complexity of the new Crossrail transport system, providing a compliant BS 9990 fixed fire-fighting system has its challenges to provide and assist the fire brigade, as well as protection for emergency personnel.
Crossrail require installation of a fixed fire-fighting system in all Central Stations and a separate system to cover Portals, Shafts and Tunnels conforming to TSI-SRT (Technical Specification of Interoperability relating to Safety in Railway Tunnels), LU 1-085 (excluding tunnels), ROGS (Railways and Other Guided Transport Systems) and Sub-surface regulations, amongst others.
Satisfying the above documentation and liaison with the Fire and Rescue Service became the challenge and proposing a hybrid system was inevitable. Consideration for anticipated fire size, space, filling times and accessibility all became key factors for the initial design.
This, subsequently, borne the following approach through agreement with London Fire Brigade;
Due to long supply lines to the hydrants located in the Stations and Tunnels, pipework would be automatically charged to head pressure (highest point on each system) via a permanent stand-alone water storage tank. Calculations were provided confirming the operational fill time was over 2 minutes in all cases, a threshold taken from LU guidance documents.
For protection of the emergency services during real-time operation, Pressure Regulating Valves were required for all areas to be set at a maximum of 8 bars.
It was also agreed that Tunnel systems would require a combined flow of 2000 l/min and Stations requiring the industry standard 1500 l/min.
Breeching Inlets would conform to the industry standard in regards to the positioning and supply.
This paper will discuss the factors made in the design proposal of the Fixed Fire-Fighting system, assumed over-engineering and summarise, perhaps simplify guidance for similar future projects.
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