Services play key role in delivering BREEAM ‘Excellent’

CHP, natural ventilation and LED lighting are just some of the services installed to deliver an energy-efficient cultural centre for Brent Council. Jai Rennison of LJJ has the details.

Pressure on local-authority funding has prompted many councils to approach upgrades to public services with a more creative strategy. For the London Borough of Brent, that has meant selling development land to the rear of the existing library to pay for a new cultural centre, ‘The Library at Willesden Green’, while designing a more efficient building-services installation. The new centre combines contemporary library services with spaces for art, study, socialising and performance.

The existing library at Willesden Green was no longer fit for purpose. Rather than bringing the building up to minimum standards with repairs, the council decided to create a new cultural centre, while preserving the old library building and reducing long-term operational costs through energy-saving and micro-generation.

The 1980s library building was demolished while the 1894 ‘Old Library’ was retained. A new 4-storey cultural centre was constructed adjoining the old library with a new link reception. A private development of apartments behind the new centre provided the capital for the public-sector scheme.

Designed by award winning architects Allford Hall Monaghan Morris (AHMM), the BREEAM ‘Excellent’ project features a highly efficient 27.5 kW solarPV installation on the roof and shares a CHP with the residential scheme, which provides energy for the hot water and heating systems along with a contribution to the building’s electrical load. LJJ was brought in to carry out design development and installation of all M&E services.

The energy centre is located below ground in a triangular-shaped room under the car park and serves both the residential scheme and the new cultural centre. LJJ was responsible for designing and installing the CHP, calculating the size of the unit to help the development meet London’s energy targets and manage the scheme’s energy costs, without over-specification.

Specialist lifting teams spent more than a day lowering the 5.5 t CHP unit through a hole in the ground. LJJ then wheeled the 5 x 2 m unit into place in the extremely tight cavity; contrary to normal practice the team installed the CHP first before installing the pipework around it.

Installing the pipework took around a week, with the team working in very cramped conditions. Once fully installed and connected, the CHP was left in place ready for switch on following completion of both the residential scheme and the cultural centre.

The energy centre also has two 850 kW boilers, which were lowered into position behind the CHP. The project included creating a makeshift entrance with a drop stair for access to the work area. This was inspected every four weeks by a health-and-safety professional to ensure the work environment was safe.

The ventilation strategy for The Library at Willesden Green was developed to minimise the building’s cooling load, with a natural-ventilation system linked to temperature sensors set at 21°C to open the windows a millimetre at a time. A multi-sensor weather station on the roof assesses wind and rainfall; it is linked to temperature and CO2 sensors within the building. Additional cooling provided as required from two large air-handling units installed in the third-floor plant room.

Specialist humidification equipment has also been installed for the archive and museum areas, with wall-mounted units connected to sensors to ensure optimal atmospherics.

LJJ, contractor, Energy efficient building systems, energy efficiency
BREEAM ‘Excellent’, the ‘Old Library’ at Willesden Green and the linked new 4-storey cultural centre.

Heating is provided by trench heating units in the floor voids, connected to the CHP.

The floor voids were adequate for installation of all underfloor services, including small power and Cat 6a data. However, extremely restricted ceiling voids presented a challenge and the LJJ team had to install high-level power, lighting, fire and security cabling through the floor of the level above.

The conduit for these elements of the electrical installation had to be passed through the reinforced concrete of the floor above, and the LJJ team worked with the engineer’s plans to mark out the installation one floor at a time.

On the third floor, where the high-level installation could not be carried out from the roof, some of the services were mounted on the surface of the ceiling, where they will remain on show as a ‘feature’.

LED lighting has been installed throughout, connected to a DALI-based programmable lighting control system with dimming functionality, absence detection and daylight sensors.

In the atrium, high-output LEDs ensure functional lumen levels, regardless of the amount of natural light entering the building, while lighting in the balustrade handrails creates a feature.

Acoustic baffles have been installed perpendicular to the lights to help control noise levels in open-plan areas.

The facility is now fully open to the public, creating a diverse cultural environment and a new community hub without costing the earth!

Jai Rennison is operations director with M&E contractor, LJJ.

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