Also online at: www.dijonline.co.uk 110 THE door industry journal summer 2019 Timber & Metal Doorsets Silence of the Jambs Doors with an acoustic rating are being increasingly specified in commercial, healthcare, education and industrial settings, as well as residential. But the performance of an acoustic door is only as good as its seals. Ordinary fin or brush seals simply will not do the job of blocking sound from passing through the gaps around the door. Michael Spoors of Norseal runs through some of the issues to consider when building or specifying acoustic door sets. It is not only the obvious places you’d think of that need attention paid to acoustics: recording studios, home cinemas, and the like. It is increasingly common to use acoustic engineering in residential apartment properties and other settings where sound can affect the environment and quality of life of the users and residents. In education settings for instance, comfortable sound levels are one of the primary conditions necessary for an effective learning environment. If there are background noises or a high decibel rating inside a classroom, students could struggle to hear adequately, or may find discomfort from straining to hear. It’s also easier to bec ome distracted. As such, acoustic design is an important aspect of the government’s regulations for school buildings: “Each room or other space in a school building shall be designed and constructed in such a way that it has the acoustic conditions and the insulation against disturbance by noise appropriate to its intended use.” These requirements within the Building Regulations apply specifically to teaching and learning spaces where the permissible upper limit for indoor ambient noise levels in a classroom, teaching area or small group room are 35dBA for a new build and 40dBA for a refurbishment. However, consideration may also be applied to adjoining areas that may impact on learning environments like corridors or meeting areas. The acoustic performance of doors is also increasingly in the spotlight for door schedules in office environments. Regulations to control noise in the workplace state that employers should consider the design and layout of workplaces, workstations, and rest facilities to reduce noise. But more than just meeting minimum regulatory performance levels, studies have shown that well-designed sound environments in offices help to improve concentration and enable better communication. In office environments, privacy is also a key issue driving the acoustic insulation of workspaces. When sound is generated, the ‘loudness’ refers to sound pressure and is measured in decibels (dB). When sound strikes a surface, some will be reflected, some will be absorbed and converted to heat, and some will pass through the structure, losing energy as it travels.