Complexities of Curtain Wall Flanking Transmission – A Case Study


  • Kelly Kruger Building Science Engineering Ltd.
  • Robert Ogle Building Science Engineering Ltd.


Curtain wall construction is very common in modern commercial buildings. The continuous external façade can lead to significant limitations on the sound isolation between adjacent rooms, separated either laterally or vertically. Flanking transmission of curtain wall systems is very difficult to predict at the design stage of a project. Manufactures do not routinely measure this parameter. The scarcity of data is partly due to a lack of laboratories that have the necessary specialized test environment. Generic flanking transmission loss data is of little value because of the large variation in curtain wall assemblies. Designers are often left with best guess approximations based on previous experience. These factors  also  make it difficult to significantly improve flanking transmission of an existing curtain wall installation.

This paper describes a project where significant flanking along the curtain wall resulted in poor sound isolation between floors. Due to the complexity of the junction between the curtain wall and the floor structure, several potential flanking paths were identified and evaluated. It was possible to alter each flanking path individually so that the incremental improvement of each step could be quantified. After implementing several modifications, an improvement of approximately 15 dB was observed across a wide frequency range.

Additional Files



How to Cite

Kruger K, Ogle R. Complexities of Curtain Wall Flanking Transmission – A Case Study. Canadian Acoustics [Internet]. 2019 Oct. 16 [cited 2024 Jun. 22];47(3):54-5. Available from:



Proceedings of the Acoustics Week in Canada