"Sustainable Sound Insulation" - LABC Magazine - Summer 2007

By Dr. Sean Smith, Depute Director Building Performance Centre, Napier University, Edinburgh.

Introduction
In terms of new build housing some of the recent advancements being made in design detailing, construction practice, waste awareness and reducing the ecological foot print would have been unheard of during the 1990’s. The drive from government and the house building industry towards greater sustainability, and meet the challenge of one-planet living, has had positive knock on effects over a wide range of industry sectors.

One sector which has seen a significant impact is in acoustics and sound insulation for attached housing. New regulatory processes such as Robust Details for Part E, monitoring by building control and improved site practices by housebuilders has significantly improved sound insulation in new build dwellings. New acoustic construction products and more recently supporting guidance from the Code for Sustainable Homes have together created a focus towards a more sustainable approach and the health and well being of home occupants.

At a time when the general noise levels and potential types of noise sources are on the increase this concentrated and multi-disciplinary approach is leading to improved sound insulation standards. One often forgets that these new innovative practices, procedures and improved design details which we adopt now will create homes that will serve our future generations well long after we are gone. It is also as equally important that the positive steps taken in the last few years should be maintained and built upon further to address new challenges that await.

Acoustic Construction Products
The construction product sector has seen an expansion in products for improving sound insulation. Many of these products are from recycled sources. The floating floor treatments used to reduce footfall noise in apartments are often derived from recycled foams, such as supplied by Icopal-Monarfloor or the A. Proctor Group. Even the chipboard surface flooring is produced from secondary or recycled timber or wood waste.

Developments in the recycling of car tyres has led to an expanding range of products to provide resilience and vibration damping (where vibration converts to heat and is absorbed within the material). Examples include the Isorubber materials for under or over screeds or the acoustic floor cradles from InstaCoustic.

Advancements in the wood materials sector has led to the development of acoustic quilts and batts made from wood fibres, often from what would have been low strength, waste or secondary wood. Blown cellulose fibres from paper also have good acoustic absorption properties.

Sound absorption is an integral component of sound insulation. Developments by glass mineral wool manufacturers such as Isover now incorporate up to 80% of their material from recycled glass bottles. Using recycled and not raw materials also reduces energy usage.

In terms of concrete and blockwork construction this encompasses almost 80% of the house building sector. Dr Fouad Khalaf of Napier University is opening new frontiers for this sector using recycled materials which will enhance structural, thermal and acoustic performance.

New innovations such as the portable green grinder from 2G Environmental may be the keystone to multi-product site waste recycling and immediate tracking of waste from construction sites. This can then feed back into the construction product manufacturing process.

The metal industry has been recycling for many years but recently the “push to be greener” and fuelled by the world price increase of steel has resulted in new product developments. Cullen Building Products more known for being the UK’s leading manufacturer for metal connectors and joist hangers have also recently developed new acoustic connector products which have significantly higher strength, higher acoustic performance but use 30% less steel.

The above is just a brief snapshot of examples of how the product industry is supporting the house building industry. Perhaps we should be doing more to inform the general public of the positive economic effects they can contribute towards UK industry by recycling of household waste, utilisation of local authority recycling centres and avoidance of landfill.

Attached Housing and Apartments
The changes to Part E since 2003 and 2004 and requirement for pre-completion testing (PCT) or registration with Robust Details (RDL) has led to some of the most positive changes and performance improvements to any building regulation sector. This was achieved through the extensive national co-operation provided by LABC, building inspectorate, manufacturing sector and crucially the house building industry.
The robust details approach has provided expert third party inspection and random sample testing and led to a reduction in wasteful remedial works. The RDL performance tracking in conjunction with a world leading sound insulation national database has resulted in quality improvements across England and Wales.
The ability to identify local, regional or national corrective actions where poor performance is identified and track each RD provides a high confidence and high performance system approach. This is in line with the ethos behind the Code for Sustainable Homes and hence robust details inclusion under Health and Well Being in the Code. Figure 1 shows the improvements in compliance as a result of this innovative approach when compared to previous studies on sound insulation compliance where no such scheme existed before.

Summary
The use of more sustainable products towards one-planet living, such as in the acoustic products sector, does provide a positive contribution, however small, in the great sphere of sustainability issues. Such a positive step forward for new homes and the high levels of sound insulation performance of RDs, with an average of at least 7 decibels above the regulations, is extremely positive for our future generations and the homes they will inherit. Perhaps this decade marks a critical starting point in moving away from being “the waste generation” and driving towards a legacy of sustainability and improved health and well being for all.

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