Thermal Comfort in Office Buildings in Line with a New German Acoustic Guideline

Abstract New office buildings use the thermal capacity of the structural mass to provide thermal comfort (TABS). The technique of TABS provides stable thermal conditions in rooms and is perceived to be a long-term energy efficient solution. A priori, this kind of technique is not compatible with traditional acoustic ceilings, covering a room from wall to wall. If the room acoustics is neglected and does not meet the current acoustic standards, this has often enormous impact on the discomfort, cognitive function, absenteeism, satisfaction, the physical well-being as well as the emotional well-being of the occupants. How can we quantify the acoustic and thermal impact of free hanging acoustic solutions on slab's cooling capacity? How does this finding stay in line with new parameters written in the international standard ISO 3382-3 and target values of the upcoming new German guideline VDI 2569? The purpose of this paper is to show the acoustic and thermal tests that have been conducted (6 rooms – Free hanging units (FHU) and baffles), the set-up used (3 timeframes combining 4 scenarios 30%, 45% and 60% coverage with FHU & baffles), the measurement methods and gives data to encourage dialogue and coordination between the acoustician and other building engineering disciplines. The results are giving a clear indication of a much lower impact of high ceiling coverage rates than assumed. In other words, the impact of the users’ behavior on the thermal conditions by e.g. window opening is critical and coverage rates below 60% became secondary.