Old Oak Common Station in West London, is being built as the interchange for HS2 as it enters London, linking the new high-speed line with conventional rail to the West of England, Wales, Heathrow, the Elizabeth Line and local transport connections. The new station will be one of the largest transport interchanges in the country, and it is the largest subsurface station ever built in the UK.
"Smoke downstands" in railway buildings and infrastructure terms are generally vertical, active fire and smoke barriers, designed to prevent the spread of fire and control smoke movement to protect escape routes. They extend downward from the ceiling to create compartments that can effectively trap hot smoke and toxic gases at a high level, especially for large, open spaces like station concourses, tunnels, and atria, allowing time for safe egress and protecting against further spread of fire and smoke.
At Old Oak Common Station, the precast concrete smoke downstands are an important part of the fire engineering strategy managed by the BBVS Joint Venture (Balfour Beatty, VINCI, and SYSTRA) and have been designed by WSP and Wilkinson Eyre. These are essential for the safety and security of this massive 850m long underground "box" structure, which will house the six new 400m high-speed station platforms. The distinctive curved, interlocking roof structure is also designed to allow fresh air to circulate naturally, with the smoke downstands fully integrated into this high-level architecture, as a sealed barrier to prevent smoke from descending into the passenger concourse and platform levels.
Technically, in terms of Fire Integrity and Standards, the smoke downstand barrier must comply with BS EN 12101-1:2020 Smoke and heat control systems, plus TfL Fire Engineering Standards for sub-surface environments, and provide 120 minutes of integrity, or integrity and reduced heat transfer (e.g., E120 or EW120 ratings), to allow for safe escape. The best solution for sealing the structural movement joints in the precast concrete sections of the smoke downstands was investigated with extensive research and assessment. Additional testing on site-produced full-sized panels was also carried out to confirm the performance, by WarringtonFire at their specialist facilities in Warrington and High Wycombe.
The optimum solution was confirmed as the advanced Emseal Emshield DFR/WFR-CE fire resistant movement joint system was selected as the optimum solution. Emshield DFR/WFR is a CE marked system with EN1366-4, 240 mins (4-hours) fire integrity and thermal insulation certification that also:
- Accommodates joint movement of +/- 50% i.e. A total movement capability of 100%
- Joints that are 100% watertight and smoketight
- Accommodates changes in direction in both the horizontal and vertical planes
- Accommodates 3-dimensional movements including Shear, Vertical and lateral joint expansion/contraction
- Excellent STC (Sound Transmission Coefficient) for acoustic barrier performance
- High Thermal Insulation
- No damaging mechanical fixings are required into the structure.
- Fast, cost-effective installation.
As the preferred specialist fire protection contractors, Kilnbridge Fire Protection teams have been involved throughout the assessment and testing, including the production of the trial samples for fire testing, and then in the successful site installation of the Emseal Emshield systems, provided in a range of bespoke widths from 60 to 100mm. The installation was carried out over 3 phases, each involving the installation of around 180 linear meters of Emshield WDR-CE in the smoke downstand joints.
The NCC Movement Joint specialists have supported the Old Oak Common project team all the way, from initial design office evaluation right through to successful completion on site. NCC provided all necessary design data, CAD details and FEA (Finite Element Analysis), and assisted throughout the evaluation and testing, then practical installation training for the teams on site.
There are many different applications for the Emshield DFR/WFR-CE Systems on many different horizontal and vertical joints in many different building and infrastructure projects, including high-rise and deep basement developments, multi-story car parks, tunnels, stations, airports, data centres, stadiums and arenas, as well as for secure nuclear and military facilities etc. For technical and practical support with the design, assessment and installation of fire rated, structural expansion movement joints in your building and infrastructure projects, from the design office right through to successful completion on site, contact NCC Movement Joints, and our specialists will assist you.
