Surround sound

Originally designed to screen off dirty, unruly-looking urban building sites, Layher’s Protect system has found a new function – as a sound absorber. Nowhere is

this being better demonstrated than at the Royal London Hospital in Whitechapel, which is undergoing a major refurbishment. Keeping the noise down is essential on this project: not only must the demolition works go unnoticed by the public, adjacent hospital areas include children’s wards and maternity facilities.

The refurbishment forms part of the largest ever PFI healthcare project and involves the demolition of 14 buildings to make way for a custom-designed 21st century hospital. ‘We needed a mobile system with effective noise control that could be moved as the project proceeds,’ says Skanska project director, Mervyn Lowe, who selected Layher’s system.

At Whitechapel, subcontractor TRAD has fixed the Protect acoustic screen to support scaffolding. It comprises aluminium panels with a sound-deadening foam fixed to the inside face that reduces sound transmission by, on average, 26dB.

Sean Pike, Layher’s UK MD, says the erection process was not without challenges. ‘Because there are no holes in Protect for wind to pass through, the wind load increased dramatically, so tying the system to the building required extra effort.’

Sound-stopping capability is not the only advantage of the Protect screens, says Pike.

‘It looks good. In fact, we have an alternative model which is in-filled with translucent polycarb instead of aluminium and on one site in Germany the public assume it to be the finished elevation of the building because it’s been up for two years.’

Keeping the noise down is essential on this project. Adjacent hospital areas include children’s wards and maternity facilities

Although the Whitechapel fix is in aluminium, specifiers think it more attractive than alternative screening methods such as scaffolding and plastic sheeting. Lowe agrees that ‘it presents an aesthetic appearance’.

The system in use at Whitechapel was designed in conjunction with TRAD. ‘They worked it up and we verified and qualified its performance,’ says Pike. It was during this process that Layher realised extra absorption would be needed. ‘We ended up inserting a mat, which adds another 5dB of sound transmission protection. We’d experimented with this approach before, but only in Europe and only on a very small scale.’

Health and safety regarding dust particles has also been addressed. ‘The panels have a rubber seal that keeps all the dust inside – especially important if there is any asbestos removal scheduled,’ says Pike.

When it came to designing the elevation screening, there were some bespoke requirements for the fix. Evacuation requirements, for example, have been met by installing doors and placing stairs at key points.

As much specified for its original intention – site screening – Layher believes that Protect’s durability brings another benefit too. It can be re-used time and again, says Pike, whereas scaffolding and plastic sheeting solutions generate a considerable amount of waste.

At Whitechapel however, the primary concern was sound absorption and, critically, it has impressed Jane McLean, the children unit’s head nurse. Her verdict? ‘The demolition was barely noticeable,’ she comments. ‘It’s felt like we’ve been wrapped in cotton wool.’