# Criterio differenziale L. 447/95

> Check of the Italian differential immission criterion (Law 447/95, DPCM 14/11/1997 Art. 4): 5/3 dB limits and exemptions.

Practice: acustica
Field: ambientale
Status: Tool
Tag: L. 447/95, DPCM 14/11/97, Italia
Method, assumptions and limits: <https://www.stline.it/en/wiki/criterio-differenziale/index.md>

Page: <https://www.stline.it/en/tools/italian-differential-criterion/>

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Demonstrative tool for checking the differential immission criterion inside dwellings. For the daytime and night-time periods it computes ΔLr = Lr,ambient − Lr,residual and compares it with the limits in DPCM 14/11/1997 Art. 4 (5 dB day, 3 dB night), handling the §2 negligibility thresholds for windows-open and windows-closed measurements. An Italy-specific legal criterion — not a generic international method.

This file is a **descriptor**, not the tool's documentation: it says what the tool computes and by what method, in summary. Formulas, assumptions, validity conditions and limits are in the wiki linked above. The tool runs in the browser at the page given.