## The Evolution of Acoustic Regulations: From EN 12354 to ISO 12354:2017
In the field of building acoustics, a significant change occurred in 2017 with the release of ISO 12354 standards. Compared to previous documents, they represent a true innovation, as they replace the European regulations EN 12354:2002 and ISO 15712:2005, integrating and restructuring the foundations of acoustic design. This transition is not just nominal, but also implies a harmonization of performance index calculation practices globally.
### From a Local Approach to a Global Framework
In the early 2000s, acoustic calculation models were developed by the European Committee for Standardization (CEN), a group of European experts. However, with the transition to ISO, the development process took on a global profile, making ISO 12354:2017 valid worldwide. This change aims to ensure that best practices and the most up-to-date technologies are available to designers around the globe, promoting harmonization that enhances the reliability of acoustic assessments in various contexts.
### Innovations in ISO 12354:2017
One of the first noticeable differences is how these new regulations structure calculation models, clearly differentiating outcomes based on the types of structural elements considered. Buildings constructed with “Type A” elements adopt the mathematical relationships already proposed in EN 12354:2002, thus maintaining a certain degree of continuity with the past. However, for “Type B” buildings, lateral transmission calculations (Rij,w) are now carried out using the normalized sound insulation index Dn,f,ij,w.
An interesting aspect of ISO 12354 is Appendix D, which provides detailed guidance for calculating the increase in sound insulation (ΔRw) for finishing elements such as drywall partitions or floating floors. This appendix, while referencing existing procedures from the 2002 standard, includes modifications and new formulas for evaluating the performance of other external coverings, such as ETICS (External Thermal Insulation Composite Systems) or ventilated walls.
### A Renewed Approach for Internal Coverings
For internal coverings as well, ISO 12354 introduces a systematic approach similar to that of 2002. Before calculating acoustic performance, it is necessary to determine the system’s resonance frequency (f0). This value is then used to derive ΔRw from a specific table, simplifying and making the calculation process more accessible.
### Attention to Detail and Potential Errors
However, despite the innovations, ISO 12354:2017 is not without criticism. A significant typographical error concerns the calculation of resonance frequency in formulas D.1 and D.2. The correct term of 160 has been erroneously replaced with 1/2π, introducing a major discrepancy that could generate an incorrect coefficient of about 1000. Such misunderstandings could lead to inaccurate calculations, and it is hoped that a correction will be published soon to avoid complications in future projects.
### Improved Results and Safety Margins
Despite the imperfections, the new calculation models present results that, in various cases, can be considered “better” than previous standards. This offers engineers and designers interesting opportunities, but it is essential not to let their guard down. It is good practice to maintain an adequate safety margin in calculations regarding passive acoustic requirements. Let us remember that proper installation of the…
