As part of a wider environmental strategy aimed at reducing carbon emissions, the National Assembly for Wales certainly recognised the benefit a sustainable approach to its refurbishment program and facilities management can bring.
The National Assembly appointed specialist consultant, ARUP to identify relevant opportunities to reduce its carbon footprint. Based on this initial study, the National Assembly approved a project involving the replacement of existing car park lighting at the Assembly’s Offices in Cardiff Bay with state of the art LED lighting. This one project would cut CO2 emissions by 6.4 tonnes per annum.
Under a framework agreement, WYG Management Services Ltd provided Project Management support to the Assembly. As Project Manager, WYG engaged ARUP to provide a detailed car park lighting design, then both managed and procured the replacement lighting via competitive tender.
Gareth Williams, Associate of ARUP comments, “Advancement in LED technology has led to significant gains in light output and optical control to the point it is now a feasible option for exterior lighting applications.”
Williams adds, “More importantly, when compared to conventional light sources, LED presents significant energy savings and in the long-term will certainly reduce maintenance costs.”
Following a review of the marketplace, ARUP shortlisted and selected a number of LED solutions and determined a model design. It was Kingfisher Lighting’s LED-in that provided a cost effective solution to achieve the requirements.
In close partnership with ARUP Designer Imran Jaura, the lighting design team at Kingfisher Lighting confirmed and finalised the proposed design. The key design challenge was to ensure the required lighting specification could be achieved using existing lighting columns and positions. The original lighting scheme column height was 4m. However the new scheme required a mounting height of 5m. This was achieved via CMB Electrical, engineering a solution using column extensions, raising the mounting height to 5m.
The original lighting scheme utilised 50 lighting points, each fitted with 70W SON “globe” style fittings. Imran Jaura, commented “An assessment of the existing lighting scheme highlighted that some lighting positions had failed and due to the age and discolouration of the remaining luminaires they were not achieving an effective light output.” As a consequence, the required lighting specification was being compromised and was not providing adequate lighting levels to the CCTV cameras.
The new scheme based on the 36 LED ST optic LED-in reduced the number of fittings to just 33! The scheme comprises 17 lighting points with single mounted versions around the periphery of the car park. The main area of the car park was effectively lit by 7 additional twin or triple mounted versions to ensure existing lighting positions were maintained to minimise the physical intrusion to the car park.
Stewart Weaver, Principal Project Engineer for Kingfisher Lighting comments, “The original scheme consumed 18,400kWh annually. By switching to a LED light source the new scheme reduced this by 64% to just 6,600kWh, whilst still providing the original lighting specification of 20 Lux! ”
The scheme was also designed using multiple lighting circuits. This would allow lighting points on the periphery of the car park to be switched off during out of office hours, making further annualised energy savings yet without compromising the required lighting levels. Based on CIBSE LG6 for public car parks, the lighting specification was set at an average maintained illuminance of 20 Lux and achieved 0.25 uniformity.
In addition to energy savings, the quality of the lighting certainly improved. Compared to the existing SON based scheme, with a typical colour rending index of Ra 25, LED-inprovided a totally different visual experience. With an Ra of 75 and a colour temperature of 6000°K, the night time environment would be much clearer and crisper to users of the car park and the operators of the CCTV system!
In addition to sustainability, the effective containment of light pollution is also a key issue facing specifiers and designers alike.
Given the relatively low mounting height of 5m, ordinarily the design team would be conscious of the possibility of glare. Thanks to the LED-in Comfort Light Optic, this certainly would not be an issue. Each LED light source is positioned within an individual mirrored reflector housing providing precise optical control and minimal glare. Each individual reflector dissipates the emerging beam across the reflector surface thus softening the visual impact and focusing the beam distribution. In addition to minimising the level of glare, the precise optical control also ensures overspill is contained. Finally, given the flat glass profile of LED-in, the level of upward light being produced would be zero.
