Trent's Pre-Glazed Cladding Contributes to Sustainability Objectives at Great Western Hospital
The concept of sustainability is about using the earth's resources in a way that will not prejudice future generations. The UK Government's sustainability strategy can be traced back to decisions following the Earth Summit in Rio in 1992, and in 1998 it published a paper entitled "Sustainable Construction - Opportunities for Change". The key issues were to cause minimum damage to natural and social environments; minimise the use of resources; enhance quality of life and be acceptable to future generations. Further reports published by the DETR identified more specific targets for
sustainable construction including: quality and durability of construction; re-use of materials; improved efficiency; reduction of waste and pollution and improved energy efficiency.
Carillion Building Special Projects set out for the Great Western Hospital in Swindon, a PFI project involving a new 55000 m2 hospital on a greenfield site near J15 of the M4, to be a flagship environmental project. Environmental measures on the job range from design issues to materials used, construction techniques and waste handling. Maximising the use of prefabrication by undertaking the installation of window frames, glazing and insulation in the precast concrete factory rather than on site, is a key element in attaining these sustainability objectives.
The precast concrete contractor, Trent Concrete, was appointed over a year before starting on site, in order to derive maximum benefit from the specialist's experience and expertise and to allow adequate time for manufacture. Trent was awarded the £1.7m contract for the design, manufacture and erection of 7600 m2 external cladding, following a two-stage tender. Two-stage tendering is a procurement route that enables competition but leaves room for value-engineering by specialist contractors. Carillion Building Special Projects and Trent Concrete had worked successfully together on many previous contracts, including several partnered projects, providing an important background relationship based on trust and cooperation. By bringing the interfacing specialist contractors together with the design teams early in the process, considerable time and cost savings can be made along with major reductions in duplication and waste.
One of the main reasons for specifying precast concrete cladding was a desire to dispense with external scaffolding. On a multi-storey project of this size, scaffolding represents a considerable cost and also hinders other work from starting at the earliest opportunity.
With off-site fabrication, components are delivered to site on a just-in-time basis in a carefully planned sequence, so that a single crane movement takes the unit from the delivery vehicle to its final position in the building. Construction is faster, there is less pollution from dust and noise and there are fewer traffic movements.
In addition, fewer people and materials are needed on site, which in turn increases safety, overcomes the combined challenges presented by the on-site skills shortage and the vagaries of the British weather and simplifies construction management.
A development of this strategy is to make units as large as practical to reduce the number of components to be erected, minimise the amount of joints and fixing components and further speed up construction. At Swindon, the panels measured a maximum viable size of 7m x 4m and weighed up to 14 tonnes, which enables a rapid on-site build time. Feedback has indicated that key end-user visitors to the site have been astounded by the progress being made, creating a positive perception all round.
Manufacturing buildings in controlled factory conditions with permanent employees means that skills and knowledge are continuously applied, resulting in much more efficient use of labour and improved quality, accuracy and reliability. Frame to panel jointing can be more rigorously inspected, for instance, meaning that air leakage through the building fabric can be kept to a minimum. In addition, pre-glazed panels make the early enclosure of a dry envelope possible, which in turn allows following weather-sensitive trades to start work earlier. This is especially important in hospital construction due to the significant amount of M&E services to install.
Trent Concrete, along with all others involved on the project, has undertaken a strategic review of all aspects of its work to ensure that it causes a minimal level of environmental impact. This covers how materials are sourced and manufactured, recycling waste wherever possible and minimising traffic movements.
It is clear, therefore, that precast concrete has a very valuable role to play in construction efficiency, safety and sustainability.
Client: The Hospital Company in partnership with the Swindon & Marlborough NHS Trust
Architects: Whicheloe Macfarlane HDR
Contractor: Carillion Building Special Projects
Engineer: TPS Consult Ltd.
Window supplier: Broderick
Notes
Trent Concrete is a specialist precast concrete contractor, producing high quality bespoke architectural cladding and structures.
Providing a complete solution from detailed design development through skills-based manufacture to on-site erection using its own teams, Trent Concrete partners with leading developers and specifiers to ensure that their projects gain maximum benefit from prefabrication.
Trent Concrete's precast solutions make a major contribution to improved quality, certainty, sustainability, safety and efficiency in the UK construction industry today.
The company has worked on some of the most prestigious projects of recent years, including The Scottish Office and the Toyota GB Plc and Thames Water headquarters buildings, and the quality of its work is consistently recognised in the form of industry awards. Trent Concrete was founded in 1917 and employs more than 200 people.
Editorial contact: David Walker
Tel: 0115 987 9747
Email: lmason@trentconcrete.co.uk
Trent Concrete Limited - e-mail: quality@trentconcrete.co.uk