9 Sound Isolation
Noise Design Criteria
Single figure values in dBA cannot be taken as being reliable for design purposes as they give no indication of the frequency spectrum. The list below may nevertheless be of some use in stating an approximate indication of loudness (dBA) and also the approximate NC and NR (see Figures 16 and 17).
Figure 16 ISO noise rating (NR) curves
Figure 17 Noise criteria (NC) curves
Environment |
NC/NR index |
Equivalent dBA |
Entertainment: |
||
Concert hall, theatre |
20–25 |
30–35 |
Lecture theatre, cinema ... |
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