From rock-and-roll extravaganzas to awesome military displays in Horse Guards Parade, ESS’ modular stage system has toured the world and mingled with the stars.

For the past week, Horse guards parade has echoed to the sounds of the Royal Military Tattoo. The normally quiet parade square has reverberated to the thunder of the huge military display, followed by another set of marching bands in preparation for the pageant to celebrate the Queen Mother’s 100th birthday.

The tattoo and pageant have provided stage designer ESS with yet another application for its versatile Tower System, a huge truss that carries the hundreds of lights and tonnes of sound equipment that are essential to the celebration.

The horseshoe-shaped steel truss surrounds three sides of Horse Guards Parade, rising high above the heads of the assembled crowd. The square has been transformed from an empty space into a vibrant, dynamic venue alive with sound and light.

ESS developed the Tower System to construct temporary buildings. It is a modular structural system based on a standard kit of components that can be assembled to create a building of almost any shape that will exist for anything from a few days to a few years. The kit has already been used to create the Skyscape pavilion, or “Baby dome” as it was originally termed, next to the Millennium Dome. More recently, it was used to construct the Australian pavilion at this year’s Hanover Expo.

The same standard truss sections that support these buildings form the aerial truss at the celebrations in Horse Guards Parade. A 150 m long horizontal truss, supported by four truss legs, faces the square. It is flanked by two shorter 70 m wings extending either side of the parade ground to form a U-shape. The horizontal truss is actually constructed from 2 × 2 m square sections assembled from 2, 4 and 8 m long modules. The vertical towers are formed from 2 × 1 m sections in 9 and 6 m long modules.

At the base of each leg, 48 tonnes of ballast help keep the structure upright.

Cantilevered from the main truss are 12 m long fingers of small-section truss reaching out into the square. Clusters of speakers, each weighing about half a tonne, are suspended from the very tip of each cantilever. “Mounting the speakers on the cantilevered trusses allows the sound to come from the front of the crowd,” says ESS director Olly Watts.

The whole gantry system was assembled in just four days using two teams of riggers and two cranes. The teams worked in shifts, one group working from 6am-6pm, the other taking over from 6pm-midnight. With the show over, it will take about three days to dismantle the structure and clear the site.

The Tower System’s roots lie in the music industry. ESS began life in the 1970s when a couple of rock-and-roll lighting engineers landed a contract to supply the staging for a Fleetwood Mac tour. In the late 1980s and early 1990s, the company expanded and toured Europe, supplying stages for the likes of the Rolling Stones, Bruce Springsteen and Madonna. “At one time, we had 120 containers of gear flip-flopping around the world,” says Tim Norman, managing director of ESS.

With stage sets getting bigger and bigger, the company teamed up with consulting engineer Buro Happold to develop a modular structural system that could be used to construct the stage sets and build other event-type structures. It had to be lightweight and compact so that it could be squeezed into containers and shipped around the world. Hence, the Tower System was born. “We designed the system to be robust and strong. At the same time, it had to be easily assembled by unskilled operatives anywhere in the world,” says Watts. “We also had to be able to break it down into truck-sized sections for shipping.”

The trusses are manufactured from standard steel sections. “By using a standard section, we can build additional trusses and components in a matter of days,” says Watts, “rather than ordering special steel sections and having to wait months for them to be delivered.” Steel was preferred to aluminium for its inherent strength and because it is a metal that can be worked easily anywhere around the world.

Surprisingly, the modular truss system’s first appearance was not as a stage for a rock-and-roll legend but as a set for a television programme, albeit one broadcast to an audience of millions. In November 1994, ESS had won the contract to build the venue for the MTV Music Awards. The project involved constructing a temporary auditorium next to the Brandenburg Gate in Berlin. The Tower System was used as the building’s structure. Since then, the system has evolved. The MTV auditorium was in place for only 10 days but, in September 1998, ESS won the contract for Skyscape, which was to stand for up to three years. Norman says it was “a turnkey project that had to provide all the benefits of a permanent building without compromising the flexibility and cost-effectiveness of a temporary structure”.

Even though the building had a short life, it had to create the illusion that it would be there for much longer. “We focused on what people expect for a building to feel permanent. If you go into a building with steel doors and a tight fabric outer skin, you expect it to be there for a long time,” Norman adds.

The building had to house two 2500-seat cinemas that could be converted to a 3700-seat live music venue. It also had to be fully air-conditioned and provide a noise reduction of 30 dBA to the outside. At the last minute, its flexibility was tested when New Millennium Experience Company decided that the building had to incorporate a mezzanine bar for 1000 people. This wasn’t a problem.

The experience landed the company an even more testing project in Germany. The team was called in at the last minute to build the Australian pavilion for the Hanover Expo. “The original scheme had gone way over budget,” says Watts, “so both the timescale and money were tight.”

The Australian architects had already produced a scheme for the pavilion. This had to be adapted slightly so that the Tower System’s standard components could be used. “Because time was so short, we ended up using over 90% standard components for the building,” says Watts.

But by using standard components, costs and loadings were already known – as were the rent costs for the duration of the Expo. Even so, getting the pavilion built in time involved ESS engineers working with Buro Happold, the client’s Australian engineers and architects, German site engineers and German building codes.

“Being late was not an option,” says Norman. “But then, with our background in rock-and-roll, you don’t even think about going over the deadline. It is certainly not an option being late with the stage for Michael Jackson.”

The simplicity of the scheme and the ease with which it can be assembled by unskilled workers means that “we can throw 100 people at the project to finish it in time”, says Watts.

As soon as the Queen Mother’s birthday celebrations are over, the truss will be quickly dismantled into its separate modules and loaded into shipping containers. And just a few weeks later, the globetrotting Tower System will be forming part of a stage set in Australia and part of a building in Asia.