London’s newly completed velodrome presented a number of challenges from a lighting design perspective, not least the hefty requirements of high-definition television. Nick Martindale reports
When Sir Chris Hoy, Victoria Pendleton and Jason Kenny took to the track at the London 2012 velodrome for the first time in February this year, it’s probably fair to say the lighting was not uppermost on their minds.
Despite this, however, the lighting has played a pivotal role in the overall design of the new venue, which will be used to host the Olympic and Paralympic track cycling events, and will continue to do so for the duration of the Games and beyond.
The unique “Pringle-shaped” design of the building, along with the requirements for high-definition television (HDTV) and the pledge to make this a truly sustainable Games, meant that this was always likely to be both a challenge and a labour of love for those undertaking the project.
“The double-curved shape of the velodrome roof and the unique geometry of the cycling track itself set the venue apart from more traditional ones where the field of play is typically flat and therefore easier to light evenly,” says Richard Arnold, velodrome project manager at the Olympic Delivery Authority (ODA).
“The velodrome lighting system had to be designed to take into account the changing levels of the roof that lights are attached to, as well as the changing geometry of the track surface that is being lit.”
BDSP Partnership was appointed by Hopkins Architects as both the mechanical and electrical consultant and the lighting designer for the project, and in turn appointed Philips as the lighting contractor for the specialist track and infield lighting.
“The commissioning of the track lighting was quite labour-intensive, as measurements could only be carried out during hours of darkness,” recalls Farhad Rahim, senior lighting designer at BDSP.
“Measurements were carried out for both vertical and horizontal illuminations and uniformity of illumination to avoid any areas with low lighting or shadowing, and also to test for compliance within suitable limits of glare for both cyclists and spectators.”
The requirement for HDTV meant the lighting in the arena had to be able to reach 2,000 lux, with lower levels of 1,000 lux for race settings, 750 lux for elite training and 300 lux for normal training.
“Recommendations from previous Olympic Games documentation were used to establish the lighting requirements during televised events,” recalls Rahim.
“Uniformity of both horizontal (0.8) and vertical (0.7) plane illumination levels were taken into consideration for televised events, together with use of high-efficacy lamps with long service life and good colour-render properties.”
The need to switch between the different lighting levels on a regular basis also necessitated a complex central control system which included switching between luminaires when used in 300 lux mode to ensure an even spread of maintenance.
“We wanted a set regime where all the fittings would be re-lamped at just one time rather than specific ones that are used all the time throughout all the illumination levels,” says Rahim. “That was probably the most difficult aspect of the controls: getting the uniformity and selecting which spotlights would light which area of the track and then circulate round while still maintaining that uniformity and using different lights.”
Raising the roof
A further challenge was how to incorporate the lights into the roof structure, with a unique cable net arrangement eventually providing the solution. “A combined containment and hanging system was developed to both serve as a cable distribution system and provide support for the lighting and any supplementary equipment,” says Adrian James, director of BDSP.
“The containment system is articulated and follows the curve of the roof. The articulation allows for anticipated movement in the roof during high winds or snow cover and is suspended from the roof cable net nodes.”
The system itself was constructed at floor level, he adds, with all major lighting fittings, control gear and cabling already fixed into position, and each fitting supported by a “gimble” to ensure the lamp element and optics align horizontally despite the sloping roof.
“Stage lighting erectors were used to hoist the completed system into the fixed positions using temporary rigging hoist motors commonly used for stage lighting rigs,” recalls James.
The net system can also support abseilers should any maintenance be necessary prior to a televised event, but most failures can be carried out using a mobile platform.
As well as overseeing the track and infield lighting, BDSP undertook the lighting requirements in other parts of the complex, including the installation of emergency lighting.
“Should the event suffer a power failure the system will maintain 50 per cent of the lighting for 15 minutes, with a further 30 minutes for 25 per cent,” says James. “If power has not returned, lamps will be sequentially turned off with a selection maintained for three hours to aid an organised evacuation of the building.”
Discreet and neat
Outside the building, the onus was to ensure the lighting was as unobtrusive as possible. “We didn’t want a series of lighting poles cutting across the shape of the building so the concourse is effectively lit at a low level by a series of lights incorporated into the balustrades around the edge,” says Chris Bannister, partner at Hopkins Architects.
“In conjunction with light from the inside coming out through the glazing, it effectively provides a glow of the lower level, effectively separating the bowl from the ground.”
The project was finished in January this year; almost 18 months before the start of the Olympic Games. “The delivery of the lighting system was a triumph of the client, design team, main contractors and suppliers working in partnership throughout,” says the ODA’s Arnold. “The first-class delivery of the lighting system is a tribute to the expertise of all involved.”
Mother nature’s sun
Natural light plays a prominent role in ensuring the velodrome is as energy efficient as possible, despite the requirements of HDTV, which has seen an installed lighting load of 370kW for the track and infield areas.
“We optimised the roof lights so we get sufficient light over the track to allow it to be used the majority of the year without switching on the lights and to ensure we don’t lose too much heat,” says Chris Bannister, partner at Hopkins Architects.
“The final roof lights use special diffusing glass with two PVB interlayers to prevent potentially hard shadows while still providing sufficient daylight for training purposes,” adds Farhad Rahim, senior lighting designer at BDSP.
Intelligent control systems use presence detectors to ensure light use is kept to a minimum, and monitors to switch off lights once sufficient natural light is available.
In legacy mode, the aim is to use natural light for around 70 per cent of the time, without the need for any artificial light, adds Bannister, producing a background lighting load of just 2kW.
CLIENT: OLYMPIC DELIVERY AUTHORITY
ARCHITECT: HOPKINS ARCHITECTS
ENGINEER: EXPEDITION ENGINEERING
LIGHTING DESIGNER/CONSULTANT: BDSP PARTNERSHIP
TRACK LIGHTING SOFTWARE: RADIANT SOFTWARE
REMAINING AREAS SOFTWARE: DIALUX
LIGHTING CONTRACTOR/CONTROLS: PHILIPS