Sellafield Ltd Chooses Tata Steel Over-cladding Solution
Over 14,000m2 of Trisomet® 333 System insulated wall panels by Tata Steel have been used to over-clad the Pond Hall Building of the Thorp Receipt and Storage Facility at Sellafield.
The building is 36 metres tall and 192 metres long. It houses two large water ponds as part of the reprocessing of spent uranium rods.
Trisomet® 333 System met the performance criteria set and also offered good lifetime performance to minimise further re-cladding and meet the design life requirements for the project.
Rods arrive at Sellafield from all over the world. They are placed in flask containers and lowered into the ponds. They stay in the ponds for a predetermined period to allow for cooling and then undergo a separation process that recovers good fuel, which can be re-used.
The building has two distinct roofs – one consisting of natural asphalt on a deck, the other featuring the KalZip standing seam system. Its moist internal atmosphere creates an extremely similar high humidity environment to that of a swimming pool. It is also located in an extremely aggressive marine location, a few hundred yards from the Irish Sea.
Sellafield Ltd carried out performance analysis of the building envelope. Concerns were expressed over the potential long term integrity of the single-skin aluminium sheeting on the walls, as signs were emerging that suggested it would eventually require replacement.
As an initial step, over 28,000 fixings were replaced, maintaining current performance levels while Sellafield Ltd sought an appropriate permanent solution.
Preston-based contractor F.Brown plc worked in conjunction with the Tata Steel technical department, looking for the best option. Following extensive evaluation, Sellafield Ltd accepted the suggestion of the Trisomet® 333 System in double-sided Colorcoat HPS200 Ultra® pre-finished steel, covered by the Tata Steel Platinum® System Guarantee.
F Brown plc is an approved installer within the Platinum® System Guarantee scheme. This means that their workmanship is continually checked to ensure everything is being correctly installed. The warranty provides peace of mind to clients for up to 25 years. It is free of charge, covers material performance and workmanship and provides the client with a direct link to Tata Steel in the unlikely event of a problem.
All components used are covered under the guarantee through supply chain partnerships. Approved Platinum® System Guarantee suppliers are selected on the basis of their ability to meet the stringent technical criteria and performance set for each component and provide a component guarantee of up to 25 years. Specifiers and contractors are able to choose from a published list of approved suppliers.
The new Trisomet® 333 System walls at Sellafield feature Tata Steel’s Repertoire® bespoke colour matching service, to match the original cladding – an Antelope (08B21) finish for the bottom 75% of the building, with Light Grey (10A03) on the top 25%. This provides a colour scheme designed to blend into the surrounding environment.
Panels were supplied in four metre lengths to comply with site health and safety handling requirements. The thermal performance of Trisomet® 333 System helped to improve the mean temperature of the building. Installation of the panels also cut down the risk of air leakage through voids.
Reflecting on the completed project, Paul Rainford-Miller, Principal Architect, Sellafield Ltd commented: “In considering the re-cladding of the Pond Hall Building, the challenge for the design team was to come up with a cladding panel that could overcome the technical issues relating to condensation within the structure as well as tie in with the existing structural support system.
“The Trisomet® 333 System panel met the performance criteria set and also offered good lifetime performance to minimise further recladding and meet the design life requirements for the project.
“The appearance of the panel was also an important consideration and the double-sided Colorcoat HPS200 Ultra® coating offered the best in appearance and durability.
“In developing the detail design for the re-cladding system, the design team worked closely with Tata Steel and the cladding installer to answer all the technical requirements and this collaborative approach served to minimise site installation time and enabled the project to proceed with confidence.”
Sellafield Limited Project Manager Richard DeLoughry noted: “The collaboration between all the project team members from the initiation of this project, including the design team, main contractor, installation contractor, Tata Steel and Sellafield Limited as a client, has resulted in a successfully delivered project for all concerned.”