Open-plan design is widely used in modern office because of its high space utilization and convenience for communication. But at the same time, this kind of design brings one problem -- NOISE, which many influence the work efficiency.

As far as in 1960s, the scientists in other countries did related studies to find out the acoustic characteristics of open-plan office environment to establish theoretical foundation for well designed acoustic environment.

However, there are differences in language, culture and work practice between Chinese and foreign counties, so JIAO Fenglei from CAS Institute of Acoustics in collaboration with KANG Jian and ZHANG Mei from University of Sheffield carried out researches to study the acoustics characteristic of open-plan offices under Chinese language environment and relationships between subjective evaluation and objective indices.

Measurements were made in four open-plan offices in Beijing, along with a series of questionnaire surveys.

The results show that, acoustic quality is the second important factor for such office environment, just after lighting, and there is a certain degree of requirement for speech privacy. Although subjective evaluation of the acoustic environment depends on the type of work, it is generally between "neither good nor bad" and "bad". The subjective evaluation significantly correlates to LAeq and L10, so that using reverberation time only is not appropriate to evaluate the acoustic environment. Reducing speech transmission index could considerably improve the speech privacy as well as the overall acoustic evaluation. Subjective factors including the recognition of acoustic environment, loudness sensitivity, and emotional felling based on mood and tiredness, significantly affect the acoustic environment evaluation, whereas no significant influence has been found from the concentration level on work, working hours per day, age, income and position.