The Chapter of Manchester Cathedral wanted to realise its potential and ensure the Cathedral was fit for the future and so embarked on a comprehensive ‘Development Project’ in 2010. Serving a large, diverse diocese the Cathedral’s vision was to grow and make a difference in the local community by enhancing visitor and worshippers lives with enjoyable and valuable experiences.
One aim of the Development Project was to improve the Cathedral’s environmental performance and visitor comfort levels.
Failing heating system
The Cathedral had been experiencing issues with the existing buried heating pipework, originally fitted in the 1970s and 1980s. The copper pipework was failing due to thermal fatigue and water began to seep through the limestone floor and could only be stopped when areas of the heating circuits were isolated. This resulted in about 30% of the heating system not being operational and unacceptably low temperatures within the Cathedral, especially during the cold winter months.
Ramboll was appointed during the feasibility stage of the Development Project to provide building services strategies and considered a number of potential heating approaches and energy sources. The study concluded that the most appropriate solution was to replace the under floor heating system.
Upgrading the heating system with integrity
During the winter of 2011 – 2012, Ramboll carried out a survey of floor, space and air temperatures to determine the extent and locations of the defective areas of pipework. Referencing the survey results and previously recorded information, further site investigations were completed at three strategic pipework locations to establish floor construction and depth and for a greater understanding of the pipework layout.
The locations chosen were thought to house faulty and isolated pipework, ensuring the operational heating network was not damaged during any excavations. However, no pipes were found in any of the three locations identified, suggesting the underfloor heating network was not in line with the original drawings. Although the site investigations did not provide the information expected, they still proved useful and provided a greater understanding of the floor structure.
A detailed survey of the existing pipe duct routes was carried out to understand the space available and to establish their suitability for the replacement underfloor heating system. Subsequently, the decision to maintain the existing duct routes was made in order to minimise any archaeological impacts.
In addition to the underfloor heating network upgrade, a number of other interventions were being carried out on the floor area. The leaking pipework had already caused damage to areas of the floor and so large proportions of floor tiles were being uplifted and repaired. A raising dais was also being installed and this required a large floor cavity to allow for the raising and lowering mechanism. To minimise disruption and for time efficiencies, the tasks were co-ordinated so the new underfloor heating pipework was installed during the refurbishment of the floor tiles and during construction of the dais.
The previous concrete floor resulted in a number of access issues; Ramboll and the architect worked in partnership to develop a solution that that would cause minimal disturbance to the surrounding floor area if access to the new pipe network was ever needed for future maintenance. The most viable solution involved the use of limecrete as a screed and lime based mortar to secure the tiled flooring.
Improving sustainability
In order to achieve the Cathedral’s aim of improving its environmental performance, the use of a Ground Source Heat Pump (GSHP), supplemented by gas condensing boilers, was suggested and installed as the primary energy source. The new heating system establishes Manchester Cathedral as the most environmentally friendly Cathedral in the country, with a significant proportion of its heating requirements supplied by the GSHP. Ramboll also proposed the installation of a 142m2 Solar PV array, to offset some of the electrical energy used by the GSHP but this was not implemented due to budget constraints.
The Very Reverend Rogers Govender, Dean of Manchester, comments:
‘We are incredibly pleased that we can carry out this work in a sustainable and responsible way, ensuring the Cathedral is fit for the future.’
Ramboll continue to work with Manchester Cathedral, providing ongoing monitoring of the energy performance of the new system.
