The noise insulation properties of non-food-crop walling for schools and colleges: A case study

The use of sustainable materials in building design and renovation has been driven by government initiatives such as the Code for Sustainable Homes, BREEAM and other assessment techniques. This paper presents the results from in situ measurements of insulation against unwanted sound (noise) for a sustainable walling system that has much anecdotal commentary concerning its good sound-insulating qualities: straw bale walls. The case study building in which the measurements were conducted is the Genesis Centre, an educational facility in Somerset. Schools need to be acoustically effective buildings, as pupils and students need to concentrate to take part in the education process. Sound insulation measurements were undertaken according to ISO 140: 4 – 1998 and Approved Document E (ADE) procedure, or as close to these standards as possible given the ‘as built’ nature of the case study buildings. With due regard for the limitations that an in situ measurement case provides, the acoustical data collected from these tests suggests that it is possible for straw bale walls to achieve the minimum requirements of Part E with a range of values of 48–50 dB DnT,w+Ctr. These results are also compared with guidelines related to acoustics in schools and robust details.