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Kier Construction worked closely with Priddy and Unitrunk to come up with the desired cable trunking solution . |
and the electrical installation is a significant contributing factor both in the sustainability of the building and its adaptability in enabling flexible accommodation suitable for a varied range and number of tenants .
‘ We are providing a Category A shell office layout , with maximum flexibility for future tenants ,’ says Matt .
Kier Construction has subcontracted the M & E services installation to Bristol based Priddy Engineering Services .
‘ A key design strategy was the ability to provide services for floor areas such that each floor could be partitioned in two if needs be , or work equally well if a tenant wants to occupy the whole floor ,’ says Matt .
Trunking solution
While the Unitrunk trunking system installed by M & E contractor Priddy Engineering Services was not originally specified as part of this strategy , it soon became clear that it would be critical to achieving a flexible layout across the existing building floorplates .
‘ Initially , new trunking wasn ’ t part of the shell contract ,’ says Matt . ‘ There was existing trunking in the building and replacing it was not part of the initial scope of works . However , when we inspected it , the legacy installation was not up to the latest standards .
‘ As it became clear that we would need to replace the existing trunking , the revised installation also became an opportunity to achieve the flexible fit-out possibilities for potential tenants inherent in the design aims for the project . As a result , we worked with Priddy and Unitrunk to come up with the desired cable trunking solution .’
The result is a cable containment infrastructure from Unitrunk , with Unitrunk ’ s in-floor three-compartment trunking installed within channels cut into the floor slab . This approach provides a robust solution , enabling the accommodation to be subdivided into independently serviced and metered office units , while avoiding the need for a raised access floor , which would have reduced floor to ceiling heights .
Electrical services are distributed from the landlord ’ s supply via a basement LV switch room and panel , which then takes the power infrastructure to each floor via central risers .
Channels have been cut into the slab at each level to enable Unitrunk ’ s three-compartment trunking to be installed within the slab and screwed into place . The sections of trunking have then been sealed using a liquid screed that will hold it firmly in place and seal it flush to the floor level . The result is an accessible trunking network that provides a flexible infrastructure for configuration of the space by future tenants while providing a neat finish within the existing slab build up .
‘ We ’ re providing a system that is flexible ,’ explains Dave Whitehead , supervisor at Priddy Engineering Services . ‘ Future tenants have the trunking infrastructure in place and they can simply put floor boxes and carpet tiles where they like to suit their desk layout .’
It ’ s a solution that has addressed both electrical layout and buildability challenges .
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‘ One of the reasons why we liked the Unitrunk system was the ability to finish flush with the existing screed ,’ adds Matt . ‘ We had the flexibility to raise the levels up with the Unitrunk trunking . The existing slab isn ’ t quite flat because of its age , so we ’ ve set the levels then poured a liquid screed underneath the trunking to hold it in place and keep it exactly where we need to . That was a big driver for us .’
No cabling is being installed as part of the shell refurbishment contract . Levels one , two and three are essentially identical floorplates , with the basement split 50:50 between lettable floor space and plant areas , shower rooms and a bike store . The remodelled ground floor boasts the building reception and a showroom for a future tenant . The new fourth floor , essentially a fully glazed steel box on top of the building and set back , is different to other levels , and contains a raised floor , rather than in-floor electrical containment .
‘ We haven ’ t provided any trunking to the fourth floor ,’ says Dave . ‘ It will be up to the tenant to fit their own busbar , floor track and floor boxes as they see fit .’
Rapid installation
The floor trunking installed in the majority of the building is complemented by Unitrunk ’ s pre-galvanised Uniklip RIS ( Rapid Installation Systems ) cable tray suspended on channel from the ceiling .
‘ We ’ ve got three separate systems covering the ceiling void ,’ explains Whitehead . Fire alarm cabling will run in its own 75mm Uniklip cable tray , power will be laid in 225mm Uniklip cable tray and data cabling starts off on two 450mm Uniklip cable trays , before splitting off to serve perimeter areas .
‘ The floor trunking is only capable of accommodating a certain amount of data cabling , so this approach gives future tenants the ability to drop down cabling from high level to cover the perimeter of the floor plate ,’ says Dave .
Unitrunk ’ s Uniklip cable tray was specified to help reduce installation times on site while providing a robust solution that meets the high quality standards for the development . Reengineered by Unitrunk as part of the company ’ s portfolio of RIS systems , Uniklip is designed for installation with no nuts , bolts or specialist tools using the system ’ s innovative Uniklip clip and range of couplers , which can help to reduce installation times by as much as 67 per cent .
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Cables stored in channels cut into the concrete slab enable the accommodation to be subdivided into independently serviced and metered office units .
The 20 Manvers Street scheme looks to transform the existing concrete frame building into Grade A office space .
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Split services
Each floor of the refurbished building will be split in two in terms of electrical and mechanical services , with individual metering for tenants . The symmetry of the floor plates has proved conducive to that approach , but there is a need for two trunking runs down the central spine of each floor to allow for potential partitioning .
Priddy has installed 600x600mm modular light fittings to open plan office areas , with DALI lighting control . Lighting controls specialist Prolojik will commission the system after installation .
Meanwhile , 22 VRF fan-coil units provide air conditioning to each office floor , with pipework distribution via central risers to roof mounted condenser plant . This enables localised control of heating and cooling , aiding the flexible floorplate layout .
Sympathetic refurbishment
The city centre site , at the heart of the Bath Conservation Area , has necessitated tight delivery schedules and close cooperation with the building ’ s neighbours , yet the construction team is on track for completion in spring 2017 and the time saved thanks to Unitrunk ’ s RIS system has been instrumental in helping the electrical installation remain on programme .
Following the refurbishment , the building will be one of only a handful of properties with photovoltaic panels within the UNESCO World Heritage Site .
Comments James Gunning from Unitrunk , ‘ The electrical containment strategy has been critical to achieving the project ’ s aims for a flexible office building with scope for varied letting packages . By working closely with the contractor and design teams we have been able to build those aims into the electrical installation while benefiting the project with our RIS approach to product design .’
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February 2017 | 23 |