In European Country many different single-number quantities representing the acoustic properties of building elements are used to define the requirements in correlation with the applicable acoustic comfort in buildings. The concept of harmonization of these indicators will be analyzed in detail within a framework of the new action COST TU0901, which has been started recently. The paper presents both the polish requirements being in force currently and the groundwork of their amendments. New in the polish legal regulations is the future enforcement of the requirement concerning the reverberation time in rooms. Furthermore, the comparison of the level of polish requirements with the another countries is described.