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Speller Metcalfe, a UK-based building company, continues to demonstrate its strong expertise in sustainable construction.
Western Power Distribution’s new 650m2 depot in Spilsby, Lincolnshire, recently achieved a BREEAM Outstanding rating of 100.5% at design stage under the BREEAM New Construction 2011: Simple Building’s scheme, making it the highest scoring BREEAM project in the world to date, with an anticipated 101.9% post-completion score.
So what makes a BREEAM Outstanding building and how was this achieved at Spilsby?
“An approved contractor for the energy supplier, this is the tenth project in a series of mainly fast-track, BREEAM projects won under competitive tender by Speller Metcalfe for Western Power Distribution. As such, lessons learnt have been consistently reviewed to fine tune the design and construction approach to deliver excellent quality and environmental performance at best value. There has been a range of elements that has led the project team to achieving such an unprecedented score, no less complicated than interpreting the BREEAM guidelines and responding accordingly wherever possible – although achieving this is not always a simple task!” says Adrian Speller, Environmental Manager at Speller Metcalfe.
BIM
Lead designers on the project - B3 Architects - developed plans for the depot using a data rich 3D model, which has led to considerable time savings (estimated 40%) in getting the project to planning versus traditional methods. Through standardised specification developed on approaching 40 depot new builds and refurbishments this has led to a finely honed design process that provides access to a library of existing Western Power Distribution specific BIM component families and design base. As an SME working to BIM Level 2 since 2012, Speller Metcalfe were able to: Use the 3D model to inform accurate, high quality construction; Integrate 2D MEP design schematics within the 3D model to create a Level 2 integrated model; Access the model on site to better co-ordinate general construction and service routing and avoid structural clashes;
Energy Use & Zero Carbon
During design development, it became apparent that zero carbon energy performance could be achieved without exceeding budget, which was achieved through:
- A fabric first approach – this ensured excellent U value performance while delivering an airtight structure and enhanced energy performance;
- Thermal Modelling identified thermal comfort and building regulation compliance could be achieved through natural ventilation - consequently the MEP systems were simplified and mechanical ventilation and comfort cooling removed, reducing energy demand;
- Speller Metcalfe identified the rainwater harvesting system as providing poor value for money as it only served one female / one male toilet area. Capital freed was shifted to invest in photovoltaic installations which, along with the energy efficient design, resulted in a net zero carbon performance rating.
- 15/15 BREEAM credits were achieved under the Ene-1 Energy assessment with a further two innovation credits achieved for energy performance, resulting in a 106% improvement beyond the compliance requirements of Building Regulations Part L2a (2010).
Overview of Sustainability Features
The depot maximises use of renewable energy and energy efficient technologies in its design and operation. Use of refrigerants is limited with only a small, efficient system provided for the IT server room, and space heating / hot water provided by a high efficiency gas boiler with NOx emissions <39mg/kWh at 0% O2. A water leak detection system is capable of identifying major leaks alongside a 55% improvement beyond performance for sanitary fittings achieved through specification of water efficient taps, WCs, urinals and showers. Unnecessary water wastage is prevented by using solenoid valves in each toilet block - restricting the water flow when unoccupied. At least 80% of materials were sourced from suppliers with ISO14001 or BES6001 certification including the triple glazed windows and doors. All timber was sourced in accordance with the UK Government’s Timber Procurement Policy.
“The value of WPD Spilsby to the wider UK construction industry is not as a multi-million pound architectural exemplar building loaded with green bling; it is as an example of how zero carbon energy performance can be achieved without exorbitant cost. Through a fabric first approach, emphasis on sensible low energy mechanical & electrical services and natural ventilation, BREEAM Outstanding has been achieved at a cost of £1,074/m2”, adds Adrian Speller.
Very well done!
Project Team Details
Client: Western Power Distribution
Lead designers: B3 Architects
Contractor: Speller Metcalfe
Building Services: Halligan Associates
Structural Engineer: Nolan Associates
BREEAM Assessor: GreenBuild Consult Ltd
Source: Speller Metcalfe