Single envelope design using composite panels is set to change conventional frozen warehouse design, delivering significant savings to developers and operators in the highly price-sensitive frozen foods sector.
At over £5.6 billion, the UK frozen food sector is growing, driven in part by busy lifestyles, a need to reduce pressure on the family budget, plus a realization that buying frozen is far less wasteful. High quality frozen storage facilities are, of course, crucial to the industry and the town of Wisbech in Cambridgeshire, the heart of the Fens, is home to the UK’s largest deep freeze warehouse with capacity for a staggering 77,000 pallets of frozen food.
Owned and operated by Partner Logistics, which runs facilities in the UK, the Netherlands and Belgium, the building is a state-of-the-art, fully automated high-bay frozen warehouse, capable of operating down to temperatures of -25 degrees centigrade.
But size is not the only thing. What makes this building really different is the single envelope construction that heralds a complete departure from traditional frozen store building techniques. It promises very significant advantages to the industry, both in terms of capital investment, life-time running costs and, due to the high bay design, a requirement for 4-5 times less land.
Installed by ISD Solutions, the UK’s leading specialist in cold store design and construction, the warehouse is constructed using 36,000m2 of composite panels; with a single ply fully adhered membrane, over a steel frame.
Tony Wall, Managing Director of ISD Solutions explains: “Our single envelope design creates an extremely efficient building with minimal issues from frost and moisture, and much lower running costs due to the thermal efficiency and air tightness of the envelope.”
Traditional cold storage warehouses, by contrast, have effectively involved the construction of two buildings, one inside the other. This requires insulation between the shells and a roof void requiring fire prevention sprinkler systems; costly in terms of raw materials, time consuming to build and not particularly sustainable or thermally efficient. Tony Wall claims that build times are, “20% faster, and, as fewer raw materials are required, generate cost savings of 30%.”
The structure had to satisfy some demanding performance requirements, not least a one hour fire rating to one elevation and extremely high floor loadings from the racking system. A careful assessment of location, wind loadings and temperature cycles was required to ensure the design could safely accommodate normal shrinkage and expansion, as much as 40mm, and still remain airtight.
With air leakage measured by BSRIA at below 0.1m3 per hour at an increased pressure of 60 pascals, the best ever recorded at the time in the UK, the building far exceeds 0.5m3 design guidelines set by the International Association for Cold Storage Construction, all testament to ISD Solutions’ design and installation.
According to Tony Wall: “The improved airtightness allows the building to operate with a depleted oxygen atmosphere, down from 20% to 15%. It’s a little bit like working at altitude – personnel can work as normal, but with reduced oxygen, fire cannot burn so there are further cost savings on fire prevention, sprinkler systems and consequently improved insurance premiums.”
Minimizing the effects of ‘thermal bowing’, the physical distortion of the wall panels as the exterior metal skin heats up in the day, while the cold interior face contracts, was essential. With a potential temperature difference of 60 degrees on a hot summer’s day, how the composite panels are fixed in place and the design of junctions, connections and fixings were critical.
This warehouse in Wisbech was completed in 6 months with a build cost of £42 million, despite challenging client deadlines, bad weather delays and the need for specialist construction training to complete the roof works safely.
With food waste rising up the agenda, the frozen sector is increasingly important, which means more new warehouses. Rising utility costs, will also drive operators to replace or upgrade tired and inefficient facilities. Currently the UK has just four large-scale frozen food warehouses – the two largest developed by ISD Solutions. But, with more single envelope projects already underway and mounting interest from across the sector, will these sophisticated, thermally efficient, low carbon solutions be the future for frozen food?
Frozen warehouse future:
Single envelope benefits
• Shorter construction period
• Cheaper to build
• Lower running costs
• Reduced fire risk
• Highly sustainable
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