The secret trials that have helped Tasmanian stadium clear biggest hurdle

Tasmania’s proposed roofed stadium has cleared one of its biggest hurdles after secret trials involving cricketers, broadcasters and specialist lighting experts found the venue’s design would not compromise the game or the television product.

This masthead can reveal that a prototype section of the roof was constructed over a specially prepared cricket pitch at the site of the proposed stadium earlier this year.

It allowed players, broadcasters and lighting experts to test how natural light filters through the roof, how shadows move across the playing surface and whether batters can clearly track the ball beneath the structure.

The new stadium, which the AFL made a condition of entry to the league for the Tasmania Devils, has been the subject of protests and controversy among locals. Its design had also been criticised by Cricket Australia, which wanted the stadium redesigned or the roof removed because of the impact of shadows over the centre wicket.

But the testing, involving Cricket Australia, Cricket Tasmania and specialist lighting consultants, has effectively validated one of the most heavily scrutinised elements of the billion-dollar project before construction tenders are finalised.

The three-month trial centred on the stadium’s proposed roof material – a translucent polymer known as ethylene tetrafluoroethylene, or ETFE – which is already used at several major international stadiums. Unlike a fully transparent roof, the Macquarie Point design will use a matte finish intended to diffuse natural sunlight and minimise shadows cast by the roof’s steel support structure.

The potential impact of those shadows has long been considered one of the biggest unknowns surrounding the project, not only from a player safety perspective but also for broadcasters, who have been keen to understand how changing light conditions would appear on television.

As part of the trials, a cricket pitch was constructed beneath the prototype roof, where Cricket Tasmania players faced bowlers and bowling machines using red, white and pink balls. Broadcasters were also invited to observe the trials, with cameras positioned on scaffolding to test vision and ball-tracking technology under the proposed roof.

At the same time, specialist lighting consultants monitored how much natural light penetrated the roof material and whether the movement of shadows matched computer modelling completed during the design phase.

Macquarie Point Development Corporation chief executive Anne Beach said the testing was designed to ensure the selected roof material performed as expected under live playing conditions.

“We’d already undertaken analysis making sure the roof height would protect the game from impacts from miss-hits and sixes,” Beach said.

“However, light performance from a player experience perspective was important to also test.”

Beach said the matte finish on the ETFE roof had been specifically selected because modelling suggested it would disperse natural light and minimise shadows created by the stadium’s structural steelwork.

“The feedback was positive and confirmed the selection of the matte ETFE roof material set out in our design documentation, which is currently informing the bids we’ll receive soon from the construction firms competing to construct the stadium,” she said.

Stadiums Tasmania chief executive James Avery said the three-month testing program had successfully addressed concerns about how the roof would affect play.

“The findings have helped support the existing design of the roof and facilitated specific playability testing in simulated lighting – full and direct sunlight – conditions,” Avery said.

“It confirms that cricket can be played without shadowing impacting the players’ view of the oncoming ball.”

The testing represents another significant milestone for the Macquarie Point project, which has faced years of political debate over its cost, design and necessity as part of Tasmania’s bid to enter the AFL.

While much of that public debate has focused on the economics of the stadium, the roof has remained one of its most technically challenging features. Maintaining a natural turf surface capable of hosting AFL football and international cricket beneath a covered venue presents a series of engineering challenges, particularly in Hobart’s climate.

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