Daylight is an essential element in the offices of Wexford Council. The complex consists of six department blocks under a covered central public street. External courtyards lead out from the central public space and are screened in glass, while the façade appears to be a rhythmic series of glass panels.
Sustainability is fundamental to the design. The plan and section make the most of daylight and passive ventilation through a double skin exterior.
The ongoing £24 million project was started in 2006 by Nord Architects (now Robin Lee Architecture) and Happold Lighting became involved in 2007, working with Robin Lee Architecture, Arthur Gibney and Partners and the engineering teams at Buro Happold. Work started with an analysis of the daylight to check the fenestration and light wells were effective in delivering the daylight needed in working areas.
Bathed in daylight
Artificial light was to be used in a sparing way with daylight being used wherever possible. A restrained approach was adopted to echo the architectural language of the building. Only a few types of fittings are used, positioned to create a distinct character for each area.
The materials used in public and private spaces are different, and so is the lighting equipment. The luminaires, which are largely linear fluorescent and linear LED sources, are more visible where concrete is exposed, but the sources are completely concealed when a space is lined with timber, like the main staircases and council chamber.
The ACDC Fino is used in the stair areas. Laura Philips, an associate at Happold Lighting, says: ‘This was because it fitted in the handrail detail and provided the correct distribution of light.’ Mike Stoane Lighting developed a bespoke light with specific dimensions for the internal street. M100 fittings illuminate the staff canteen and public lobbies. They are necessary around the skylights when daylight alone is not sufficient during winter months.
In the offices a series of light wells in each department block ensure that no working spaces are any great distance from a source of daylight.
The three glazed elevations of the office areas are complemented by the illuminated fourth wall, which ensures the contrast is not too great and the space is visually comfortable.
Offices are lit to 300 lux with artificial lighting and are dimmed in banks in response to signals from daylight sensors. T5 Action fittings with a colour temperature of 4000K are used, and 3000K lamps wash the walls to create warmth. The glass façades are screen printed to increase solar shading and reduce glare. Specialist coatings applied to the glass further increase insulation and reduce heat loss.
During the day, the building appears as a solid surface reflecting light from the sky and surrounding landscape. This reverses at night when the inner workings of the building and layers of the façade are revealed by light emerging from the inside. The external composition of the façade at night is dominated by the 40-seat council chamber that may be in session in the evening.
As well as the civic garden, courtyards and gardens are planned throughout the complex in such a way that the landscape pervades the buildings and becomes as essential to its makeup as the stairs, offices, corridors and foyers. This strategy not only allows for planting at key locations but also ensures that the outside spaces near the civic offices are of high environmental quality.
The iGuzzini Delphi Square was used for the exterior of the building. Philips says: ‘The aesthetic was right for the exterior. A wide range of optics were available and there are several different mounting configurations.’
The lighting of the project looks simple, but it demanded co-ordination from the design team and was largely the result of collaborative working early on, when the architects discussed any problems with the multi-disciplinary team from Buro Happold. The project is an example of the way in which early discussions about apertures and cast-in areas for lighting and conduits in the structure can pay dividends.
Happold Lighting did the daylight analysis and worked on the artificial lighting with Robin Lee Architecture in areas where luminaires are detailed into skylights to support and add to the daylight. This was designed to ensure that the spaces still felt largely naturally lit even under gloomy skies.
Philips says: ‘The Breeam design rating for the building overall was “Good”, but initial records indicate the performance is closer to “Very Good”.
The fully connected lighting loadings overall are 14Wper square metre. However, a third of the lighting in the of ces and main public atrium is off during the day so a gure of 9W per square metre is more realistic.’
A Philips digital lighting control system is installed and works automatically, dimming the lighting based on the amount of daylight in response to signals from a series of sensors. An override at the main reception controls all the public spaces.
There is local scene setting in the staff canteen and council chamber. Philips says: ‘The light quality in the spaces changes quite dramatically from day to night, as was the intent.’