Acoustic classification of the real estate units

July 22, 2010 saw the publishing of the technical standard UNI 11367 titled “Acoustic classifi cation of housing units - for assessment and verifi cation procedure on site.” It is a real report card that goes to defi ne the criteria for the measurement and evaluation of the acoustic requirements of the buildings measured on site. The standard provides for the subdivision of the property units into four classes, based on the obtained acoustic performance. The use of classes will help to inform the users of the real estate based on noise characteristics knowing that the Class I corresponds to the quietest level and Class IV to the loudest level.
The acoustic classifi cation applies to all buildings except those in agriculture, handicraft and industry, while, for schools, hospitals, nursing homes and clinics, the acoustic requirements are defi ned in the Appendix A (normative) of the same rule.





It is important to note that the overall assessment (eg. Class I, Class II, ...) is based on fi eld measurements and not on design data. It must also be accompanied by mandatory detailed assessments for each descriptor considered (apparent sound reduction, standardized sound insulation of the facade, etc ..) in order to give a complete representation of the acoustic performances. The determination of the class is done exclusively by acoustic consultants, who is bound to correctly and fully apply the standard. 
At present, the UNI 11367 is a reference of good technique and is not a mandatory standard. Therefore, compliance with the UNI 11367 is required only if it is required by contract terms.


However, it should be remembered that the Law 12/28/2015 - No. 221, came into force on 2 February 2016, cites the UNI 11367 art. 23 reporting: “The public authorities [...] foresee, in tenders for the energy efficiency of schools, and in any case for their renovation or construction, use of materials and design solutions appropriate to the achievement of the values specified for noise indicators by UNI 11367: 2010 [acoustic classification of building units] and the UNI 11532: 2014 [interior acoustic characteristics of confined spaces]. In the calls for tenders there will be evaluation criteria for the bids [...] with scores rewarded for products containing post-consumer materials or arising from the recovery of waste and materials resulting from the dismantling of complex products in the percentages established by the decree referred to in paragraph 3 of this Article “.
In the table below, we see the values of the parameters descriptors of performance characteristics of building elements to be used for the acoustic classification of real estate units. 


High performance ensures compliance with UNI 11367




Normalized sound insulation of facade  D2m,nT,w [dB]

Apparent sound reduction index of vertical and horizontal partitions between diff erent residences R’w [dB]

Normalized impact sound pressure level between diff erent residences L’n,w [dB]

Correct sound level introduced by continuously operating equipments Lic [dB(A)]

Correct sound level introduced by discontinuously operating equipments

Lid [dB(A)]

I ≥ 43 ≥ 56 ≤ 53 ≤ 25 ≤ 30
II ≥ 40 ≥ 53 ≤ 58 ≤ 28 ≤ 33
III ≥ 37 ≥ 50 ≤ 63 ≤ 32 ≤ 37
IV ≥ 32 ≥ 45 ≤ 68 ≤ 37 ≤ 42

Performance limits (UNI 11367)

There are widespread hopes for a broad application on a voluntary basis of the UNI 11367 because only in this way, is it possible to maximize the acoustic standards of the entire chain of construction, a fenomenon that has already been verified in areas that are very different; think, for example, of the revolution that occurred with the introduction of the energy consumption class of electrical appliances, now considered an essential parameter by the consumer for the choice of the best product to buy.