Law 447/1995: the framework law on noise pollution
Summary
TAV. 00The framework law on noise pollution: it sets principles, competences (State, Regions, Municipalities) and instruments to govern noise. From it descend the acoustic classification of the territory, the limit values and the acoustic requirements of buildings. For design it introduces two key assessments: acoustic impact and acoustic climate.
Scope of application
TAV. 01It concerns fixed and mobile sound sources, the acoustic planning of the territory and the requirements of buildings. The limit values are set by D.P.C.M. 14/11/1997 and the passive acoustic requirements by D.P.C.M. 5/12/1997; Regions and Municipalities handle implementation and controls.
In depth
TAV. AThe frame for noise
Law 447/1995 is the framework law on noise pollution: it defines principles, competences (State, Regions, Municipalities) and the instruments to govern noise as an environmental and health factor. From it descend the implementing decrees on limits, building requirements and the qualified figures.
The acoustic classification of the territory
The Municipality divides the territory into six acoustic classes, from Class I (particularly protected areas: hospitals, schools) to Class VI (exclusively industrial areas), each with its own day and night noise limits. The zoning is the precondition: without it, you do not know which limit applies.
Acoustic impact or acoustic climate? (the hard case)
Two assessments that are often confused. The acoustic impact documentation concerns whoever introduces a noise source (an activity, an infrastructure): it shows it will not exceed the limits towards the outside. The acoustic climate assessment concerns whoever inserts a sensitive receiver (schools, hospitals, dwellings) near existing sources: it shows the site is quiet enough for that use. The first looks from the work outwards; the second from the environment towards the work.
| Assessment | When it is needed |
|---|---|
| Acoustic impact | new noise sources (activities, infrastructure) |
| Acoustic climate | new sensitive receivers (schools, hospitals, dwellings) near sources |
The differential criterion
Beyond the absolute zone limits, inside living spaces the differential criterion applies: the difference between ambient noise (with the source active) and residual noise (without it) must not exceed strict thresholds, stricter at night. It is the criterion behind most neighbour disputes; it does not apply below certain noise levels, considered negligible.
The figures and the instruments
The law establishes the qualified acoustics technician, entitled to sign the assessments, and assigns the zoning and controls to the Municipalities, coordination to the Regions and the general criteria to the State. The passive acoustic requirements of buildings — facade insulation, between units, against footstep and systems noise — are set by D.P.C.M. 5/12/1997.
Why it matters
Noise is the most underestimated and most litigated form of pollution. Law 447/1995 makes it a design parameter: acoustics is not a finishing touch but a performance, proven before (climate/impact) and built afterwards (passive requirements). For premium architecture, silence is a material.
Key points
TAV. K- Framework law on noise pollution: principles, competences and instruments (Law 447/1995).
- The Municipality classifies the territory into 6 acoustic classes (I-VI), each with its own limits.
- Two distinct assessments: acoustic impact (new sources) and acoustic climate (new sensitive receivers).
- Differential criterion: inside dwellings the difference between ambient and residual noise has strict thresholds.
- The passive acoustic requirements of buildings are set by D.P.C.M. 5/12/1997 (implementing).
- The assessments are signed by the qualified acoustics technician.
Frequently asked questions
TAV. QWhat is the difference between acoustic impact and acoustic climate?
The acoustic impact concerns whoever introduces a noise source (showing it will not exceed the limits outward); the acoustic climate concerns whoever inserts a sensitive receiver near sources (showing the site is quiet enough).
What is municipal acoustic classification?
The division of the territory into six classes (I-VI), from particularly protected areas to industrial ones, each with day and night noise limits.
What is the differential criterion?
Inside living spaces, the difference between noise with the source active and without it must not exceed strict thresholds (stricter at night); it adds to the absolute limits and does not apply below negligible levels.
Who signs the acoustic assessments?
The qualified acoustics technician, an authorised figure listed in the national register.
Where are the acoustic requirements of buildings?
In D.P.C.M. 5/12/1997, the implementing decree of the framework law, which sets facade insulation and insulation between dwellings, from footsteps and from systems.
What if the Municipality has no acoustic zoning?
Transitional limits apply until the classification is approved; but the zoning remains the correct reference for knowing which limits apply.
Glossary
TAV. G- Classificazione acustica
- Division of the municipal territory into six classes with noise limits.
- Impatto acustico
- Assessment of the noise produced by a new source towards the environment.
- Clima acustico
- Assessment of the existing noise at a site where a sensitive receiver is inserted.
- Criterio differenziale
- Limit on the difference between ambient and residual noise in living spaces.
- Tecnico competente in acustica
- Professional qualified to draw up and sign acoustic assessments.
- Requisiti acustici passivi
- Acoustic insulation performances of buildings (D.P.C.M. 5/12/1997).