In the area of workplace design, both the technical requirements of the workplace and inter personal concerns of the employees are of decisive importance in order to establish a suitable working environment. Often conflicts of interest arise due to the antagonism between disturbing noise and desired speech intelligibility. An employee who has to concentrate a lot at his/her workplace can be distracted both by disturbing background noises (air conditioning, fans, aggregates etc.) caused by low sound absorption as well as disturbing high speech intelligibility of background conversations. When assessing such situations, the speech transmission index (STI) is an important parameter. Influenced by the reverberation time and the signal-to-noise ratio, calculating the STI is a powerful tool for assessing demanding work environments.The present work deals with the determination of an STI mapping on the basis of numerical simulations using ray tracing methods as well as calculations of the sound energy density distribution in room acoustics. The experimentally validated models can be used to optimize the workplace configuration to meet technical requirements as well as social concerns of employees.