Success on this project required early involvement and close working between all supply chain members. Conventional buildings they may be, but they have been produced by less traditional means. Sited on a former goodsyard adjacent to Paddington railway station, the 150 000 m2 development is now well underway thanks to off-site prefabrication and modularisation, with pre-planning and teamwork essential parts of the process.
Getting onboard early had new meaning to the construction team here. Talks between the different team members began before formal appointment had been confirmed, and specialist contractors and suppliers were brought in at the tender stage.
"The whole philosophy of the job was set out by Development Securities, the client, right from day one," states Patrick Carroll, services project manager with main contractor Bovis Lend Lease. "Even the submissions were done more like an open partnership approach."
Ian Battle, project manager with m&e contractor Haden Young agrees: "The client likes to work in partnership, so it wasn't a matter of competitive tender, it was more a matter of presentation."
At the first stage of a two-stage tender process a target cost was given, which the competing firms had to state how they could meet. Then, unusually, personal interviews were carried out with each of the supply team members, personalities and approach playing a major part in the selection.
Bovis was employed for Phase one of the project on a JCT 98 contract, heavily amended to reflect the partnership approach. The selection of the two firms took place at the same time as m&e consulting engineer Faber Maunsell was producing a concept services design.
Haden Young applied a partnership approach from the very start. Battle explains: "Discussions with suppliers took place very early in this job, at the first tender stage. Everybody was geared up to start developing drawings, so by the time we got to second stage tender, we were able to put firm prices together."
This early design work, combined with an extensive value engineering process, effectively altered the pricing structure for the project. The initial cost plan involved Haden Young and Bovis commiting to a shared risk and reward partnership with the client, where each would share a third of any deviance, whether profit or loss, from the target cost. Bovis remained on this risk and reward system on a capped 50:50 basis with Development Securities throughout Phase one, but a guaranteed maximum price (gmp) was agreed with Haden Young at the second stage tender.
"There were some fairly detailed stipulations on what was included in the gmp. But once that gmp was agreed, as far as Bovis was concerned that secured a lot of the job and took a chunk of our risk out," explains Carroll.
Battle explains: "Because so much design work had been done the risk was minimised. When we got to the second stage we knew exactly what we were in for. We needed to do that, because the only way this job was going to be installed on time was to modularise and prefabricate as much as possible. The fact is though, if we hadn't got the design sorted out that early, there's no way that prefabrication could have happened. Lesson one in prefab is to put a design in from day one – you can't retrodesign. If you are going to do it, you've got to build the rest of the building in certain ways as well. The whole team has got to buy into the modularisation concept."
With Haden Young employed at the predesign stage, maximum use of the contractor's knowledge and experience could be used in the design. "They were in very much earlier that we would normally expect an m&e contractor to be there. That's why the procedures of this job have worked," stresses Carroll.
To facilitate teamworking as well as overcome a lack of space on site, Faber Maunsell relocated to Haden Young's Watford offices to work on the detailed design. "We only have one set of drawings," explains Carroll, "we don't have one set of drawings issued by Faber Maunsell, which were then developed by Haden Young. When the drawings came out they had both their names on it, so it was effectively already approved by Faber Maunsell and it just went in for formal comment by the architect."
"Everybody was encouraged to think differently," stresses Battle. Witness the use of busbar for the distribution of electricity throughout the floors. As well as helping to save time, and provide a neat, above-ceiling installation on the floors, this reduced the number of electrical risers needed. Such changes were only possible because of the early appointment and close working of the teams. "If the ceiling had already been sorted out and everybody had been geared up to a different concept, and then when we arrive on site with only a couple of weeks to go before installation, there's no way that we can change," stresses Battle.
Prefabrication on the project ranged from the risers – which arrived on site in nine-metre sections, complete with busbar, control panels and floor plates – to packaged rooftop plantrooms. To support the 300 tonne weight of the rooftop plant, Haden Young designed a modular steel framework, which was prefabricated with pipework in place. The contractor's early involvement meant it could co-ordinate with the structural engineers and suggest lengthening the structural beams through the roof to support the frame from the foundations, removing the need for any further structural support at roof level.
Battle estimates that around a year has been saved from the project time by the offsite working and teamwork approach. Installation of m&e services to second fix level took one week per floor. On a recent comparable project this took nine weeks using traditional methods, he reports. The ceiling modules were produced and delivered at the same rate, allowing a single team of installers to work alternately on both offices.
Profile
PlayersProject: Paddington Central
Client: Development Securities
Project manager: Bovis Lend Lease
M&E consulting engineer: Faber Maunsell
Main contractor: Bovis Lend Lease
M&E contractor: Haden Young
Contract details
Tender date: June 2000
Form of contract: JCT 98
Contract period: April 2001 to July 2002
Providers
Mechanical suppliers
AHUs: McQuay
Boilers: Hoval
Chillers: Powermaster
Control valves: Satchwell
Computer room air conditioning: Watford Refrigeration
Drainage above ground: BM Stainless
Ductwork: Galloway
DX Systems: Watford Refrigeration
Extract fans: Woods
Fan coil units: Diffusion
Floor grilles: Trox
Humidifiers: Vapac
Insulation: Quest
Pumps: Grundfos
Radiators: Zehnder
Sound attenuation: Galloway Acoustics
Sprinklers: How Fire
Water Heaters: Heatrae Sadia
Electrical suppliers
BMS: Invensys Climate Control Europe (formerly Satchwell)
CCTV: Reliance High Tech
Cable: Pirelli
Controls: Invensys Climate Control Europe
Emergency luminaires: Thorn
Fire alarm: ADT
HV/LV switchgear: Schneider
Lighting controls: Simmtronic
Luminaires: Thorn
Power busbar: Schneider
Public address: ADT
Security equipment: Reliance High Tech
Standby generation: Countryman
Trace heating: Delta T
Prices
Total cost (phase one): £85 million
M&E services: £17.784 million
Mechanical services cost: £12.181 million
Electrical services cost: £5.603 million
Source
Electrical and Mechanical Contractor
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