Final designs for HS2 Ltd’s vent shaft headhouse at Little Missenden. The headhouse will provide ventilation and emergency access to the high-speed railway’s 10-mile-long Chilterns tunnel below.
The headhouse is one of four which will be built above vent shafts leading down to the high-speed rail tunnel below, and, is similar in style to the HS2 headhouse at Chalfont St Peter which was announced earlier this year.
The tunnel will be set back from the main A413, the single storey design is inspired by the barns and historic agricultural buildings found in the surrounding area. This has influenced the building’s dark and neutral colours, which have been designed to fit into the surrounding landscape.
Around the headhouse, the landscaping has been designed to screen the building through planning and bending it into the landscape. The Little Missenden headhouse will sit atop a 17.4m diameter, 30m deep ventilation shaft that will reach down to the railway’s twin tunnels below. It will contain fans and other equipment that has been designed to regulate air quality and temperature in the tunnels, remove smoke in the event of fire, as well as providing access for the emergency services.
In addition to the headhouse, the site will include an autotransformer electricity station, stairs, and vent building both of which carry similar design cues. The plans have been drawn up by HS2’s main contractor Align JV, a team made up of Bouygues Travaux Publics, Sir Robert McAlpine and VolkerFitizpatrick.
HS2 Ltd’s senior project manager, Mark Clapp said: “Designs for the Little Missenden headhouse are the culmination of many hours’ work to develop a scheme that both serves the needs of operating HS2 and is in keeping with local design heritage.
“Our four-week engagement with the community is an opportunity for them to tell us their views of the scheme. As part of this programme we’ve arranged three online webinars where people will hear about how the designs were developed.”
Daniel Altier, Align Project Director said: “The Align team has worked to significantly reduce the scale and visual impact of the structure. We are therefore excited to be revealing our designs for the Little Missenden vent shaft headhouse. Our designers have worked closely with stakeholders to design something that provides the operational functionality within the smallest possible footprint, reducing local construction and environmental impacts as far as practicable during the build.”
Ian Thomas, Engineering Manager for designers Align D, said: “Set back from the A413 dual-carriage way, the single-story buildings will be wrapped in a landscaping solution that minimises their visual impact. Taking its inspiration from the style of local barns and other agricultural buildings, the headhouse is designed to fit into the surrounding landscape. The pre-weathered grey zinc roof will age naturally over time, without loss of robustness or quality.”
“These proposals are the result of integrated work across the design team, alongside collaborative engagement with the Chilterns AONB Review Group.”
This latest news accompanies a four-week public engagement programme which seeks people’s views on aspects of the scheme, including the design of the headhouse along with plans for the landscape and the area’s ecology.
HS2 Ltd will be holding three online webinars on 4th, 9th and 12th November during the engagement period, more information can be found here. The engagement period ends on November 25th 2020.
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