# Improving Engineering Design Using Smart Evaluation of Indoor Acoustical Climate of Dining Places
## 5 Evaluation of the Acoustic Climate of Selected Rooms in  
Dining Buildings  
The literature devoted to dining places presents many analyses based on difficult and complex computational models or models that require a specialised knowledge of acoustics [4; 9; 24; 27; 28; 29; 31; 36; 37]. There is still no simplified method for acoustic climate evaluation in such rooms, especially at the design stage, when the designer makes decisions concerning the intended use, size, or equipment of a dining room. Previous knowledge is scattered and may not be understandable for building process participants who do not have a specialised knowledge of interior acoustics. The results of the computer and literature analyses formed the basis for developing a method for evaluating the acoustic climate of dining places during the design process. The evaluation of the acoustic climate of dining places includes the selection of appropriate values for a sub-index (a detailed description of the values was presented in previous sections of the paper). Owing to the different significances of individual characteristics, different class values were assigned. The sub-indices that have the most significant influence on speech intelligibility, including the sound-absorbing elements' index, room's volume index, and capacity index, were assigned the broadest of 0-5 or 0-4, respectively. These parameters have a high impact on reverberation time and speech intelligibility. Therefore, the remaining parameters indirectly influenced the acoustic climate and were less important, which was reflected in the smaller value range of 0-2. Table 4 presents the values of the individual sub-indices. The proposed method is a simplified version of acoustical designing for architects and designers who are not familiar with acoustical problems such as the reverberation time or speech intelligibility. The proposed values of each sub-index provide them with a direction of action. The method indicates to the architect potential acoustical problems, such as a lack of absorption, excessively large volume without any partitions, simplified shape, or an excessively high noise background. The proposed limits for each sub-index were developed based on a literature review, conducted analyses, and the author's experience. * The W\({}_{\text{A}}\) limits were proposed based on computer simulations. The proposed values apply to materials with different sound absorption coefficients used in the simulations (see Section 4, Table 1), from reflecting material (0.0-0.25), through average absorptive (0.3-0.55), to highly absorptive (0.6 to 1.0). As shown, absorption has a greater influence on the STI index than capacity; the proposed values of the sub-index are maximum, from 0 to 5. This sub-index depends only on the sound absorption of the ceiling (or its equivalent area, while other surfaces are highly reflective). * W\({}_{\text{C}}\) limits were proposed based on the values presented by [PERSON] [36] concerning ambient noise as a function of acoustic capacity corresponding to the quality of verbal communication. Based on the simulations (see Section 4), the proposed values for this sub-index are smaller (from 0 to 4) than those for sub-index W\({}_{\text{A}}\) (from 0 to 5). As shown, capacity has a smaller impact on the acoustical climate. It should be noted that the reverberation time RT, which is necessary to estimate capacity, can be calculated using any simple calculator available on the Internet (for example, [59]). * W\({}_{\text{V}}\) limits were proposed based on the literature analysis presented in Section 3 and the author's experience. The sum of all sub-indices yields the \(W_{R}\) index, which is a numerical description of the acoustical climate of the dining places. The \(W_{R}\) acoustic climate index for the above-described types of dining places can take values ranging from 0 to 20, where the corresponding acoustic class describes each value as follows:  
\(W_{R}=20\div 16\) is the result for a dining place with an acceptable acoustic environment.