The ICCM Journal | Winter 2009 | V77 No. 4 13

coloured glass and heat pumps

An update: the New Crownhill Crematorium in Milton Keynes

Hello again! I’d like to take this opportunity to update you on the progress of the design and construction of the new Crownhill Crematorium. A good deal has happened since my last instalment in the Spring 2009 Journal.

New Consultants:After the closure of MK Council’s architecture department, architecture MK, last December 2008, the project architects were seconded to work inside our Client’s department, MK Environmental Health. We had to make progress without a Quantity Surveyor and a Mechanical and Electrical Engineering Services Consultant until the procurement process for replacing them had been completed.

Quantity Surveyor:The first of our new consultants, the quantity surveyors, joined us on 22nd May 2009. Following a start-up meeting, I set them off working on their first task, which was to provide us with an updated budget costing for the project. After a week, we found out to our surprise that we were under budget. This was excellent news, as it meant that we didn’t need to do what every architect dreads which is to have to make cuts in the project to balance the cost against the available budget. As a result, our end user Client asked us to make a small addition to the scheme which was to extend the promenade and rill by a few metres. This was a simple amendment to make which improved an area that had previously been reduced in length by half, following advice received from the previous Quantity Surveyors. Knowing that the project was on cost, the quantity surveyors were asked to commence the preparation of the Bills of Quantities.

Mechanical and Electrical Services Consultant: The second of our new consultants, the M+E Services Engineers joined us on 18th June 2009. After their start-up meeting, they were set a long list of tasks to look at to help us check the co-ordination of the Mechanical and Electrical Services design. This had been completed by architecture MK by December 2008, but as the design had developed in some areas since architecture MK was closed down, certain areas had to be reviewed.

The first of these was the ventilation of the cremator room. We were aware of the vast amount of heat energy that needs to be dissipated from the cremators, but wanted to handle this in a manner that was sensitive to the existing architectural vocabulary. We were also aware that extract fans can generate a great deal of noise, and as we were ventilating the chapel adjacent by means of the Monodraught Windcatchers, it was essential that noise from the cremator room air extracts could not reach the chapel. It was also essential that we followed the D4 sustainability policy, so this was solved by means of solar powered “Monovents”, where solar panels power air extract fans inside a device that is of the same appearance as the “Windcatchers” that will be located over the chapel, staff accommodation and waiting area.

After a detailed thermal modelling exercise was undertaken by our M+E Engineers, it became apparent that the use of natural ventilation, the thermal mass and underfloor heating would not be sufficient to maintain the desired internal temperatures at both peak summer and peak winter

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conditions within the chapel area. This is mainly due to the high loads imposed by naturally ventilating a space that is densely occupied. The Client and I were keen to look at sustainable options for providing a “boost” heating and cooling arrangement to supplement the main systems at peak times. To meet the requirement, a ground source heat pump system was proposed. By installing some closed loop boreholes filled with thermal grouting to maximise heat transfer, the energy from the ground can be harvested for use within the main chapel area for heating. Similarly, the constant relatively low temperature at that depth can be used for free cooling in summer.

As the temperature of the ground below 4 metres is generally constant throughout the year (at about 10-14deg’C), energy will be saved. This is because the heat pump system will not have to harvest energy from the ambient air which generally ranges from -4deg’C to 30’degC. Performance co-efficients improve dramatically and up to 6 kW of heat for every 1 kW of electricity input can typically be achieved. This provides far greater benefits in terms of energy efficiency, running costs and carbon emissions over conventional electric or gas fired means. This system added to the capital cost of the project, but a simple

Chapel interior viewed from the lectern

Catafalque viewed from the choir seating

long term cost benefit analysis indicated that the savings in energy were well worth the initial investment. Other areas reviewed were the staff accommodation, where the need to provide acoustic noise reduction in the form over overhead “troughs” similar to those provided in the chapel necessitated a review of the lighting.

Julian Stocks, Glass Artist:It was always our intention to incorporate coloured glass into the end elevation of the chapel, the sanctuary window and the glass screens to the chapel exit and committal room. However, we didn’t think that traditional leaded stained glass lights were appropriate. We were looking for something that was contemporary, which would also exceed the elemental thermal requirement of the Building Regulations. Following a meeting with Pilkington Glass, we discovered a company called Proto Studios who specialise in the manufacture of large sheets of screen printed, coloured, toughened and heat soaked glass that can be incorporated into high performance argon filled double glazed units. Through Proto Studios, we discovered the highly renowned coloured glass artist Julian Stocks. Julian attended a meeting with us on 29th May 2009 and impressed myClients, my colleagues and I so much that he was

Choir area – looking towards the rear of chapel

View of the Japanese garden from the chapel

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commissioned to produce some proposals. Julian returned a couple of weeks later with not only some beautiful coloured presentation drawings but also a model of the end elevation of the chapel. Julian explained that he had picked up on the theme of water in the design of the building. He had noticed that the building’s design incorporated not only the lily pond, but the fountains and rill, the SUD’s ponds and the rock water feature in the Japanese garden. As a result, his scheme, named “Aqua”, incorporated swirling forms that could be interpreted as waves, or ripples in the surface of a pond or lake. The scheme also included small touches of bright colours - reds, yellows and oranges, together with intricate detailing describing the geometry of the cycloid roof form.

Architect:The final new consultant to join the team was the new architect, who attended a two day handover meeting on 8th and 9th July 2009. The Environmental Health Architecture

Chapel image

Team continued to work on the project until the handover meeting took place. By the time of the meeting, the architectural working drawings and specifications were complete, leaving little for the new architects to do to complete the work stage.

Tender:By the end of July 2009, the Bills of Quantity were completed, and the project was put out to tender on 3rd August. Tenders were received on 28th September 2009.

Newt Mitigation:The completion of the destructive search, (that is necessary as the completion of the newt mitigation process), was due to be completed in early October 2009, and construction is due to commence on site at the end of that month. Completion is due in March 2011.

Adrian Morrow RIBA

Chapel window Sanctuary window