The Enterprise Centre in Norfolk is a fascinating and exciting project with a focus on the use of local materials, occupant comfort and an innovative lighting strategy. The building is part of the University of East Anglia and is in the top-list for the greenest building in the UK, aiming to achieve both the demanding Passivhaus standard and BREEAM Outstanding rating.
The building hosts a range of facilities for students from the University of East Anglia and in support to new Start-up companies, which need space for business workshop, networking and office areas to develop ideas and put them into practice in an inspiring atmosphere. The Centre is intended to encourage the connection between businesses and students and in the meantime is conceived to keep students focused and motivated.
Designed by the well-known Architecture firm Archetype, this University building is a great example not only for energy efficiency but also for its low-carbon embodied energy, due to the use of local materials prefabricated within 30 miles from the site.
One of the most important target for this building was to achieve a complete construction with a predicted lifespan of about 100 years, therefore durability and flexibility were main concerns throughout the design. In order to do so, the University of East Anglia Climate Team simulated different scenarios through the Passivahaus software, PHPP, to assess the most sound and feasible solutions. Finally, the design was optimised in regards to thermal mass, glazing ratio, shading and natural ventilation providing a range of possible options for a lifespan of 87 years.
The construction firm Morgan Sindall, in collaboration with the architects from Archetype, developed an interesting thatch cassette solution that could be prefabricated offsite and be ready to be erected once on site.
Ben Humphreys, Archetype project director, commented: “The thatch concept was a way of explicitly identifying this as a low-carbon project that uses locally sourced materials. It’s a way of using a traditional material in a modern way, in a prefabricated way“. As a matter of fact, the thatch cladding is clearly a symbol for vernacular architecture, and despite being an ancient material, thatch features great insulation properties, it is a waterproof material with a long lifespan. This pioneer prefabbricated cladding system makes this building stand out from the crowd and encourages discussions on the particular construction techniques used, which could be replicated in other projects.
Specifically, each timber cassette system was filled with straw and measured about 3 x 1.2 m per panel with an average thickness of 250-300 mm; this layer was then posed beyond the airtight layer and it is clearly a non-load bearing element supported by the timber structure of the building. Once the timber cassettes were ready, they were transported on site and erected as a rain screen cladding. It is interesting to notice that the construction of each cassette took only 4 hours and it was done off site with obvious advantages in terms of programme even in the wet Norfolk winter months, where rainy days are quite common.
Natural light and contact with nature are essential concerns of this project.The design of the Enterprise Centre was optimised in terms of orientation, fenestration and shading to guarantee a full light diurnal cycle for occupant wellbeing and productivity.
The artificial lighting design followed the concept of ‘lighting people and their actions rather than the space‘. This means that the lighting is used to illuminate task areas with adequate amount of light according to the activity and the occupancy of the single desk . Obviously, there are comfort requirements that need to be met, so for instance corridors are lit with ceiling lighting whereas overall the lighting cabling and connection is heavily reduced.
This approach was taken in response to years of studies and research on the natural changing cycle of light from day to night and its effect on occupant wellbeing and productivity. A person in the morning requires a different lighting spectrum than in the afternoon or in the evening and this has an impact on their comfort. Specifically, the sky-blue light has a direct effect on the melatonin received by the brain and its rhythmic cycle, so if this cycle is enhanced people can experience an overall improved quality in the workspace.
The client accepted the proposal for a more task oriented lighting design, providing warmth and intimacy in the working spaces in the evenings and allowing for controllable lamps for occupants. In some cases, sensors were applied in order to switch on lighting when natural light was not available at a certain hour. As result, the lighting strategy led to a reduction in usable energy of about 80% and about 40% embodied carbon reduction due to cabling and lighting infrastructure.
Now, after a year from its completion, the building has been tested and occupant comfort was monitored through surveys. Results show that students and staff are very satisfied with the natural light of the daytime and the warm atmosphere in the evening of the Enterprise Centre.
This project will be a flagship low-carbon building design which meets a range of sustainability standards but above all with a heavy reduced footprint due to the use of local and natural materials. Its embodied energy is only 1 quarter of the carbon emissions of similar building with same shape and size. Considering an average building benchmark for embodied energy in University buildings of 845 kgCO2/m2, the target of the Centre is just about 168 KgCO2/m2.
With a budget of 11 m, “the cost came out about the same as a regular university building”. This building proves that energy efficiency, low embodied energy, occupant comfort and wellbeing can be achieved and are key measures to the future of a sustainable built environment.
Cibse Journal, Volume 8, No.12, December 2016