{"id":941,"date":"2015-08-26T07:18:51","date_gmt":"2015-08-26T07:18:51","guid":{"rendered":"https:\/\/mccoymart.com\/post\/?p=941"},"modified":"2022-06-14T16:11:54","modified_gmt":"2022-06-14T10:41:54","slug":"acoustics-in-the-built-environment-horizontal-treatment-of-the-slab-edge-in-curtain-wall-buildings","status":"publish","type":"post","link":"https:\/\/mccoymart.com\/post\/acoustics-in-the-built-environment-horizontal-treatment-of-the-slab-edge-in-curtain-wall-buildings\/","title":{"rendered":"Acoustics in the Built Environment Horizontal Treatment of the Slab Edge in Curtain Wall Buildings"},"content":{"rendered":"

Mike Carrick AMIOA, SIDERISE Technical Officer – Construction Acoustics, SIDERISE<\/h2>\n
\"Mike
\nMike Carrick AMIOA<\/small><\/div>\n

Introduction<\/h3>\n

Acoustics is an area of design that is often neglected and equally often approached as some form of \u2018black art\u2019. We rarely describe architecture in terms of sound. It is as if this sense has no bearing on our experience of the buildings we produce.
\nIndeed, when considering acoustic issues in the built environment, most people will simply switch off. With the extensive use of specialist jargon and the many ways of referring to the humble \u2018decibel\u2019 – i.e. Rw, Dnfw, DnTw, Dncw (to name but a few) – this is no real surprise. Acoustics can be very confusing with little practical guidance available.<\/p>\n

According to a survey conducted by curtain walling manufacturer Sapa, solar control and thermal efficiency are architects\u2019 top priorities in facade design, with acoustic performance coming fourth after appearance.<\/p>\n

Results of Sapa architects\u2019 survey*:<\/strong><\/p>\n\n\n\n\n\n\n\n\n
Solar control<\/td>\n6<\/td>\n<\/tr>\n
Thermal efficiency<\/td>\n5<\/td>\n<\/tr>\n
Aesthetics<\/td>\n4<\/td>\n<\/tr>\n
Acoustic performance<\/td>\n3<\/td>\n<\/tr>\n
Integrated automatic ventilation systems<\/td>\n2<\/td>\n<\/tr>\n
Integrated photovoltaics<\/td>\n1<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Information courtesy of Sapa Building Systems<\/strong><\/p>\n

As far as acoustics are concerned, the conceptual aims of any development fall into two categories. The first is the perception of the acoustics of the completed development in the eyes (and ears) of its occupiers and visitors. The second is the control of the acoustic impact on the surrounding environment – internal and external – so that the development can operate without fear of a valid noise nuisance action being brought. In delivering both, the designer must satisfy the legislative requirements as well as the client\u2019s or end user\u2019s \u2018wish list\u2019 of acoustic behaviour.<\/p>\n

Scope<\/strong><\/p>\n

\"Sound<\/div>\n

This technical paper will explain how acoustics should be incorporated into the design process to ensure that conceptual aims are successfully achieved. Specifically it will look at sound transmission between floors in a curtain walled building, in particular the common weak point formed by the movement joint at the floor slab edge. It will further detail the required properties of the seal, associated design considerations, regulatory criteria, common terminology, potential \u2018sound paths\u2019, sound transfer mechanisms and importantly how to mitigate sound transmission.<\/p>\n

Whilst this paper covers a specific condition, similar problems, mechanisms and considerations can be applied in most areas of the built environment when considering \u2018room-to-room\u2019 acoustics.<\/p>\n

Sound Transmission Paths – the Problem<\/strong><\/p>\n

    \n
  1. Direct sound transmission path<\/li>\n
  2. Flanking sound transmission path via closure detail<\/li>\n
  3. Flanking sound transmission path via facade glazing\/ structural element<\/li>\n
  4. Flanking sound transmission path via hollow mullion<\/li>\n<\/ol>\n

    The overall performance is potentially controlled by all the path components shown above.<\/p>\n

    Curtain Wall Buildings – A Problem of Conflicting Viewpoints<\/strong><\/p>\n

    Facade Engineers:<\/strong> A curtain wall is an efficient non-structural element used to weatherproof a building.<\/p>\n

    Noise Consultants:<\/strong> A curtain wall is a lightweight structure. \u2018Lightweight\u2019 and \u2018good\u2019 acoustic performance does not go hand- in-hand.<\/p>\n

    A curtain wall is designed to resist air and water infiltration, wind forces, seismic forces, and its own dead load. Modern curtain wall systems can accommodate large amounts of movement without glass breakage or water leakage. This is achieved by maintaining a movement joint between the curtain wall fa\u00e7ade and the structure of the building. The movement joint is effectively a gap or cavity between the \u2018Slab Edge\u2019 and the rear of the \u2018Facade\u2019 that needs to be effectively sealed to maintain the acoustic integrity of the building.<\/p>\n

    The seal employed would normally be expected to satisfy the following qualities:<\/p>\n