Lightweight steel-framed (LSF) construction has the potential to reach high standards regarding the functional performance of buildings. Despite the benefits of this construction system, the effect of thermal bridges caused by the high thermal conductivity of the steel structure can be a disadvantage. Furthermore, because LSF buildings have low mass and the connections between the outer and the inner sheathing of the walls are usually rigid, provided by steel studs, some acoustic performance drawbacks are also possible. Excessive heat loss or poor sound insulation are related to the external envelope behavior of buildings. Although several studies can be found regarding the influence of the steel frame on the thermal or sound insulation performance of LSF façade walls, the study of this influence from both perspectives at the same time is not widespread. In this work, the influence of the steel frame on both the thermal and sound insulation performance of LSF façade walls is studied. The thermal behavior and sound insulation are assessed using specialized software, namely THERM and INSUL, respectively. With this work it is intended to provide guidelines which can contribute to an effective design of LSF façade walls, considering both functional performances.

An important challenge for acoustic engineers in room acoustics design is related to the acoustic performance of multi-purpose auditoriums, which are typically designed to suit several performance requirements. With this intent, the analysis of several scenarios is usually performed individually, and then an acceptable solution, that may be adapted to several situations, is selected. One way of providing a more appropriate acoustic performance for each function of the auditorium is using variable sound absorption techniques to control reverberation and other relevant acoustic phenomena associated to sound perception. In this paper, the acoustic behavior of a perforated system that may be suitable for achieving a variable acoustic solution for room acoustic design is addressed. In the design of a cost-effective solution, the surface appearance is kept unchanged, while variable acoustic behavior is achieved either by closing the holes in the back face of the perforated panel or by placing a porous material in varying positions inside the backing cavity, thus accomplishing different acoustic requirements within a multipurpose auditorium. An analytical approach, based on the transfer matrix method is employed for preliminary acoustic sound absorption assessment provided by the system and to develop optimized solutions. Diffuse sound absorption is then computed and used to simulate, by the ray-tracing method, the acoustic behavior of a multipurpose auditorium to demonstrate efficient acoustic performance for different types of use.