Just two years after a fire destroyed Airedale’s European HQ in Leeds, the air-conditioning giant’s factory is back in business, thanks to Bam’s high-speed construction programme.
Project: Airedale European Headquarters, Rawdon, Leeds
Contract value: £35m
Region: Yorkshire & the Humber
Main contractor: Bam Construct
Structural engineer: AWP
Architect: Darnton B3
Start date: September 2014
Completion date: January 2016
Running a busy construction site is always challenging – but the stakes rise when it’s also an operational factory.
Nick Howdle is Bam Construct’s project manager for the £37m rebuild of Airedale’s European HQ in Leeds, which was destroyed by a fire in 2013.
It is a turnkey job, and for the final weeks of what is a very tight construction programme, Bam has been responsible for installing and commissioning the air-conditioning manufacturer’s equipment, so that the factory will be fully operational when the contractor moves off site this month.
Construction rules for all
This means Airedale’s staff and suppliers are working alongside Bam’s – and all of them answer to Mr Howdle.
“Everything they do is subject to the same terms and conditions as our own subcontractors; they are effectively part of our supply chain,” he explains.
“But they are not used to construction sites, so it’s been a challenge getting them to change their work practices. They’ve all had Bam site inductions, they all have to wear PPE, each of their risk assessments has to be signed off by me.
“By making the project turnkey, we were able to cut our construction programme by seven weeks”
Nick Howdle, Bam Construct
“Normally, on a job like this, we would hand over the completed building and Airedale would use its own suppliers for installing equipment and fitting out the factory,” he says.
“However, by making the project turnkey, we were able to cut our construction programme by seven weeks. It means the factory is operational earlier, and Bam is off site earlier so obviously our costs are reduced.
“But it makes the project more complicated to manage. Airedale will have 300 people on site in the final week of the project – on top of 180 in the Bam workforce.”
High pressure job
The client’s wish for a fast rebuild of the factory drove the decision to make the project turnkey. The tight programme has also meant construction trades working alongside each other, and extensive use of prefabrication, particularly on the project’s vast M&E installations. It is a high-pressure job.
The fire in September 2013, which ripped through the old factory in Rawdon, about 13 km from Leeds city centre, did so much damage that any thoughts of refurbishing it were quickly dismissed. “Airedale’s insurance company took the view that it would be cheaper to rebuild it as new,” Mr Howdle says.
However, the initial design presented was rejected by the insurer as too expensive at over £40m. “They had a view per sq m of what they thought was a fair price,” Mr Howdle explains.
Bam, which had been picked from a shortlist of three for the two-stage tender, had to find £3.8m of savings along with the design team and the client.
“Suppliers had thought they were not in competition, but once they realised we were going to the market, the prices quickly started coming down”
Nick Howdle, Bam Construct
The biggest cost reduction was achieved through making the project turnkey, which has cut Bam’s programme and therefore costs, and allowed Airedale to get the factory operational while the contractor is still on site.
Additional savings were achieved by relaxing the specification. “For example, the design had asked for Kone lifts, but we opened that up to other lift manufacturers,” Mr Howdle says. “Suppliers had thought they were not in competition, but once they realised we were going to the market, the prices quickly started coming down.”
Value engineering also reduced the price. The groundworks phase involved construction of a secant wall – to a maximum 16.7 m depth and 130 m long – on what is a steeply sloping site with a drop of over 10 m from north to south. Moving the wall’s position forward 6 m and reducing the volume of spoil to be taken off site achieved a saving of around £70,000.
The concrete floor slab on which the factory sits was re-engineered to reduce its thickness by 20 mm to 230 mm; this may not seem a huge saving, but over such a large area it added up to 200 cu m of concrete, and a reduction of £20,000.
The rebuilt, single-storey factory will be roughly the same size as its predecessor at 22,000 sq m. At its north end it stands around 8 m high, but because of the slope, it gains another 4.5 m at the south side.
Here, the design has included an undercroft car park with 280 spaces. A concrete podium deck 132 m wide by 60 m long, supported by concrete columns, sits above the car park. Also at lower ground level is a plant area and the main reception.
Otherwise, the new facility is entirely on one, ground floor level. The area over the car park, around 10 per cent of the total floor space, will house the offices and R&D areas. The rest is production space.
“The factory layout will be much more operationally efficient now it is on one level, compared to the previous one, where there were extra floors and mezzanines,” Mr Howdle says.
To achieve the single-level design, the groundworks phase, which started in late September 2014, included an extensive cut and fill exercise, involving 130,000 cu m of material.
This was followed by construction of the secant piled wall. Some 5,000 cu m of recycled material from the old factory, crushed to 6F2, was reused in construction of the new building.
The secant wall was completed by Christmas 2014, followed by the reinforced concrete podium deck, with erection of the steel portal frame for the factory starting at the beginning of March.
The spans are massive. The steelwork sits on a 32 m by 6 m grid, meaning only three rows of columns run through the operational space inside the factory.
Because of the tight programme, Mr Howdle decided to overlap some trades, with installation of the composite cladding and roofing starting before the steel frame was finished.
Prefabrication for the M&E – supported by building information modelling at design stage – has also contributed significant time savings.
Around a third of the project value – some £11m – is accounted for by building services, and Bam has used its in-house M&E business Bam Services Engineering for the installation.
According to Mr Howdle, this was a crucial factor in Bam winning the contract, as the same integrated team worked on two previous industrial projects: the Rolls-Royce Advanced Blade Casting Facility and the Nuclear Advanced Manufacturing and Research Centre, both in Rotherham.
“We promised the client the same team from those jobs – including myself – would work on the Airedale factory, and all but two have come across,” he says.
The main M&E challenge is the plant room, which is costing £1.3m. It has to support extreme temperature ranges, from –20 to +50 deg C, which are required for the test chambers in the R&D area. It also has 2 km of pipework, all of which has been prefabricated.
“This was all modelled in-house using BIM, brought to the site on the back of an articulated lorry and then lifted into position,” Mr Howdle explains. “It helped that this is effectively a new-build job, and that the steel spans are very big, so we could bring the artics right into the site.”
Zero pipework snags
“We would have struggled to achieve the programme without offsite methods,” he says. “BIM has also been important. It helped with clash detection, and we had zero snags with the pipework. On a £1.3m package that is highly unusual, if not unheard of.”
Probably the biggest time saving through off-site construction methods was for the two air-handling units in the R&D area. Each one is 18 m long by 4 m high and 2.5 m wide.
“We brought each unit to the site in seven parts, bolted them together, floated the whole thing across the floor and into position, and then fitted the connections at the back,” Mr Howdle explains. “Each one required four workers to move, but took just a couple of hours to install – as opposed to six weeks if they had been assembled in situ.”
Curiously, given the nature of the client’s business, the factory floor will not have any air-conditioning. “They just open the rear goods doors when it gets warm,” Mr Howdle says, “though the offices and meeting rooms are air-conditioned.”
From mid-September Bam was moving Airedale’s equipment into the factory, around half of which was salvaged from the fire and has been kept in storage.
The equipment is being commissioned in six phases over a 12-week period. BIM has been used to tag and barcode these assets.
Though still onsite finishing up, Bam handed over the building to Airedale at the back end of December, at which point the client’s manufacturing process was fully operational.
With all the time and cost pressures tackled and put to bed, all that remains now is for the contractor to complete soft landscaping and minor external finishes while gradually decamping into the in-use building.