Acoustic performance of the Double C-Block : the tune of sustainable design

Abstract

Hollow Concrete Blocks (HCB) greatly under-perform, from an acoustical point of view, due to loss of solid mass negatively impacting the wall’s acoustic and thermal performance. An innovative Double C-Block (DCB) aims to offer a competitive technology able to replace the HCB, with a design that inhibits noise transmission, by virtue of its unique geometry and embedded triple layered, S-shaped polyurethane foam. Acoustic performance of the two blocks was compared by in-situ testing of two identical test cells, as well as a laboratory testing of two comparative elements in a hermetically insulated ‘hot-box’, and calculating their respective sound reduction indices (SRI), all in line with established ISO standards. For the DCB, a maximum value of 30dB was estimated using the Mass Law theory. Although there is scope for improvement, the results are highly promising, with the DCB already exceeding in acoustic (and thermal) performance over the HCB. This should augur well for the use of the DCB in facades to mitigating traffic noise as well as domestic noise between third party walls. The purpose of this article is to disseminate scientific evidence in favour of the DCB's acoustic performance, with a potential upgrade from technology readiness level TRL4, as laboratory-grade prototype testing, to TRL6, lined up ready for full-scale production.