ARCHITECTURAL EXEMPLARS

After seven years of preparation, the Olympic Games will leave a lasting lighting legacy in London. Robert Bain reports

For seven years the UK has been gearing up to host the world’s greatest sporting event, and now the moment is almost upon us. But the Olympic Games will be over almost as soon as they’ve begun – much of the preparation is for the legacy the Games will leave behind.

London’s Olympic Park will have two lives. It will host millions of visitors over a few short weeks, with the world’s attention focused on it. Then it will transform into a permanent park and become part of a newly revitalised East London. As for the venues, some will be dismantled after the event, but the permanent structures – including the stadium, velodrome and aquatics centre – will be adapted for their long-term future.

Numerous lighting consultants and designers worked on the Olympic Park, and most of the equipment was supplied by Philips under a multi-million pound common procurement deal, helping to achieve a consistent look and feel.

The teams working on the main venues had to consider not only those lucky enough to attend the Games, but also the billions around the world who will watch events on TV, both during this year’s games and during future events.

In the four years since the last Olympic Games, broadcasting technology has come a long way, so for the lighting in the venues to be futureproof, it must work well with the latest technology – namely high-definition television and improved slow motion, which have more exacting requirements than traditional coverage.

Standard definition TV requires average lux levels of about 1,000, but high-definition TV, which is increasingly widespread, demands twice that – or more if the footage is shot at a higher frame rate. Engineers had to make sure there is enough light to allow cameras to keep the whole field of play in focus, while also avoiding lens flare that could get in the way of the action. And because handheld cameras will be used, measurements had to be taken at a grid of points in each venue that represented spots where a camera might be.

Slow-motion recording is also susceptible to flicker from gas discharge lamps. This is usually imperceptible to the human eye but becomes visible when footage is slowed down (see the difference in this demo video of Siteco LED floodlights bit.ly/ledfloodlight).
To compound the problem, slow-motion recording at London 2012 will be at frame rates up to four times those used at Beijing 2008.

Olympic Stadium | Photo: London 2012

The stadium

For the 80,000-seater Olympic Stadium (designed to be converted to a 25,000-seat venue after the games), architect Populous worked with Happold Lighting. The 14 large triangular lighting towers, each holding about 40 2kW floodlights and weighing nearly 35 tonnes, are one of the stadium’s most distinctive features – but funnily enough they were originally supposed to be much smaller. When it was realised that the angle of the lights could cause lens flare in TV cameras, the towers were made about 20m taller, standing 70m high.

Philips Lighting’s technical and design director Mike Simpson told an engineering conference earlier this year: ‘I’d like to think that by communicating and engaging early with the lighting people they’ve ended up with a stadium that works from a lighting point of view. It’s really important to get that early engagement, and not say: “There’s my stadium, now come along and light it.”’

The floodlights, which together use more than a megawatt, provide the high lux levels that broadcasters wanted, and phases can be offset to minimise flicker. Electronic hot restrike ignitors mean they can be restarted instantly (preventing a repeat of David Cameron’s anticlimactic ‘switching on’ moment: bit.ly/switchon1210).

Bids for the future use of the stadium are still being considered, but the plan is for it to remain available for athletics competitions and training.

Aquatics centre | Photo: London 2012

The aquatics centre

Zaha Hadid’s aquatics centre, which houses two 50m pools and a 25m diving pool, has lighting designed by Arup, which also worked on the athlete’s village, handball arena and Eton Manor building. The 400 and 1,000W metal halide projectors are set back in ‘lighting bubble’ recesses to minimise glare and maintain the wave-shaped curve of the building. To aim the lights over the pool, engineers dangled plastic plates on tape measures across the water.

Velodrome | Photo: London 2012

The Velodrome's low roof posed a lighting challenge

The velodrome

Hopkins Architects is very proud of the steel cable roof of the 6,000-seat Olympic velodrome. It takes the form of a hyperbolic paraboloid (that’s Pringle-shaped to you and me), and it is the world’s lightest velodrome roof by some margin.

But it didn’t make things easy for lighting consultant BDSP. The low height of the ceiling means the 356 1kW floodlights are close to the action, and hard to keep them out of shot of cameras.

Electronic gear was used to minimise flicker, making this one of the first sports venues to use such technology. Broadcasters will have the freedom to use longer clips of slow-motion footage, safe in the knowledge that it won’t be spoiled by flicker. The lights can be dimmed to different levels for training or competition.

Mike Simpson of Philips said the experience shows how developments in broadcasting can influence lighting needs. ‘You need to keep up to date with what’s happening with cameras and broadcast technologies and what broadcasters want to do with their pictures to understand what the lighting requirements are going to be for the future,’ he said.

The park

The 2.5km2 Olympic Park is key to the legacy of the Games. After an 18-month transformation, it will reopen in summer 2013 as the Queen Elizabeth Olympic Park. The lighting had to provide a dramatic, memorable experience for millions of visitors during the Games and a long-lasting legacy for East London.

Sutton Vane Associates was chosen by the ODA to write a lighting strategy for the park and public realm areas in conjunction with other consultants and designers, as well as local authorities, transport bosses and the Environment Agency. They had to balance safety with sustainability while achieving a consistent look and feel. High light levels were essential during the games, but in the longer term, lower levels would save energy and protect the plants and wildlife in the park, which will be open 24 hours a day.

Of the strategy document’s 60-odd pages, only one related to the Games themselves, says Michael Grubb of Sutton Vane Associates: ‘It was all about the legacy and achieving long term goals.’ On this basis, Speirs + Major provided an overview of how the various lighting schemes would come together.

Things change fast

Three or four years ago, choosing the products and technologies to specify for the park was tricky because LED technology was on the cusp of being able to do the job. In the end LEDs were used extensively, except for the temporary park lanterns and the downlights in the seven large ‘halo’ light masts, which use metal halide.

‘In 2008, as a lighting designer, I still had some major problems with the quality of LEDs,’ Sutton Vane’s Grubb told the EuroLED conference in June. ‘To be honest, it would have been easier at that point to have not used LEDs. But by 2009 we were quite convinced that [by 2012] we would be where we are now – the technology was evolving quite quickly. It was a brave decision, but it was an educated brave decision.’

On the other hand, the size and prestige of the project meant Grubb and the rest of the team found manufacturers were willing to be flexible. ‘If manufacturers didn’t have it, they would do it,’ he said. ‘It was the fantasy of, “It must do this, this and this, we don’t care how you do it but it must”. You don’t have that luxury on most projects.’
He is full of praise for the way the ODA handled the project, and how it was able to make quick, effective decisions. Philips supplied products that gave the park a consistent feel rather than looking like ‘a luminaire manufacturer’s showroom’, he said.

Arup also worked on the park, collaborating with architect Allies and Morrison to design lighting for 14 footbridges and six permanent underpasses. The practice lit Anish Kapoor’s Orbit sculpture, working with the artist to create a scheme that highlights the complex geometric form. Orbit will be lit in different ways for various events and at different times of day. Red LEDs are being used to light the red-painted sculpture, emitting no UV, and the cables and wiring are invisible.

Light for today and tomorrow

A combination of permanent LED lanterns and cheaper temporary metal halide ones was used to light the park – depending on the amount of light that will be needed in different areas after the Games are over.

Protecting wildlife and waterways in the parklands was one of the team’s priorities. LED light sources were used in areas where bats live, because they do not emit UV light that disturbs the moths that the bats feed on. Some parts of the park are completely free from artificial light.

The permanent lanterns use 3000K LEDs, and draw 24-106W depending on the number of light sources inside. Step-down Dali controls will make it possible to lower light levels after the games. Each lantern has a solar panel, and had to carry a PA system, CCTV cameras and banners. The temporary luminaires were simpler – with metal halide lamps controlled by switches on a galvanised column.

For the LED system, Grubb said ‘we were adamant it had to have a removable LED system’. He added: ‘Back in 2008 this wasn’t that common. Our biggest concern was, while manufacturers make big claims, failures do happen, damage does happen. There needs to be the ability to take the lamps out and put new ones in without changing the entire luminaire.’

The seven 31m ‘halo’ masts were designed not only for lighting, but as orientation beacons. Each mast has a wind turbine at the top and a 7m halo containing a dozen 150W CDM-T floodlights. Around each halo are 528 RGB LEDs, controlled by Wi-Fi. The masts also have LED uplights to light the turbine and an LED lamp at the top.

There are a total of 11,000 addressable channels across all seven masts, which provide 30 lx over a 200m by 70m area.

Grubb said of the masts: ‘I think maybe one of the biggest faults lighting designers have is that they create these wonderful things that look fantastic at night, but they can be a bit of an eyesore during the day. We were keen this wouldn’t happen.’

At the time the masts were designed, the LED technology available couldn’t have provided the required light levels without being much larger and heavier. But by the time the metal halide lamps need to be changed, there’s no reason why they can’t be replaced with LEDs.

HALO MASTS

Seven 31-metre masts were built, each with a 5m-high wind turbine at the top and a 7m-diameter halo containing twelve 150W 3000K CDM-T floodlights. The control gear sits in the base. Around each ‘halo’ are 528 individually addressable RGB LED nodes, controlled by Wi-Fi. The masts also have LED uplights to light the turbine and an RGB LED source in a node at the very top. There are a total of 11,000 addressable channels across all seven masts. The masts provide 30 lx over a 200m by 70m area.

PERMANENT PARK LANTERNS

24-106W luminaires (some columns are single-headed, some double) using 3000K Luxeon LEDs, on 4.5m and 6m columns. The luminaires have Dali step-down controls, photovoltaic panels and the ability to house PA and CCTV equipment and banners.

TEMPORARY PARK LANTERNS

The lanterns are on eight and 10-metre galvanised steel columns, containing either four or eight metal halide lamps, controlled by switches.

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