The £30m baby

You don’t really appreciate the scale of Bison’s new factory in Swadlincote, Derbyshire, until group managing director Alan Clucas unrolls a drawing about 3 m long.

The building shown is 500 m long, and contains the most up-to-date prestressed hollowcore flooring equipment in Europe, if not the world. It cost a cool £30m.

Halfway along the building is the batching plant that produces concrete for the 150 m long casting beds for the slabs. Instead of the concrete being taken to the beds, the beds move along guide rails beneath the batching plant and into the 200 m long curing area at the other end of the building. From there, the slabs are moved into the cutting area where they are sawn to length, and where any scarf joints or services cores are cut.

To streamline the cutting process even further, a CAD program controls plotters that print details about each slab on its uppermost surface. The plotters also mark the saw cut by printing three parallel lines a few millimetres apart – the middle one being the saw line. This means that as long as an operator can see the two outer lines after cutting, he instantly knows the unit has been cut to the right length.

After cutting, the units are loaded on to pallets and arranged accoring to the sequence that they will offloaded and craned into position once on site.

Despite the scale of the operation, only a few handfuls of operatives are required to run the line. The operation even has green credentials – all the wastewater is recycled and surplus material crushed for reuse.

After spending £30m, Bison is understandably reluctant to reveal too much about production capacity and staffing levels at Swadlincote. Nonetheless, Clucas does indicate that the plant increases Bison’s total capacity by one-third. He adds: “The key driver for the investment was to offer customers a more consistent and shorter lead-time. Over the past six months, lead times for wide slabs have been anytime from six to 26 weeks. Now, we able to offer eight.”

The new plant has come at an opportune time for the company, which is seeking to consolidate its position, particularly in the housing market. At present, the sales mix between commercial/industrial and residential is roughly 50:50. But Clucas says the residential side of the business has grown for three years, and apartment blocks now account for 40% of workload “and are growing all the time”.

Clucas says there are two main reasons for hollowcore’s popularity – its noise properties and its ability to resist progressive collapse. The system is even finding favour with the timber-frame housing fraternity, as “builders want a strong, level floor to build on”.

Bison is also championing the use of transducers. Every hollowcore slab is fitted with a transducer that contains a record of the date it was cast, concrete strength, the arrangement and size of the prestressing wires and design parameters such as live and dead loads. The transducers will enable clients to check whether their buildings are strong enough to deal with a future change of use.

One million pounds has been spent developing a system for casting-in lifting hooks to enable faster and safer placing of the units without the need for slings.

With Swadlincote, Bison has now invested £50m in rebuilding its asset base and incorporating the latest technology. Clucas notes: “We have got to push the boundaries. You only have to look at what happened to Hoover with Dyson to realise you can’t afford to slip up if you are the market leader. And clients want so much more these days, and all the time they want it to be cheaper than an insitu slab.”