Context

Noise produced by cooling units on the roof of a building.

The client is an active player on the national ICT services market through its offer of solution and technological platform companies for telecommunications.

At the Milan office, cooling units were installed on the roof of the server of the internal technical plant.

Such groups produced noise pollution that caused disturbance to the inhabitants of neighboring buildings, located less than 30 meters away, and higher than what is allowed by law. The phonometric measurements, performed before the intervention in one of the disturbed houses, was 57 dB(A) with the windows open.

The site and nearby homes are in CLASS IV or in urban areas with intense vehicular traffic, with high population density, high presence of commercial activities, offices and craftsmanship.

Output limit values

Territory use destination class Times of reference
Day
(6.00-22.00) 		Night
(22.00-6.00)
CLASS IV areas destined predominantly for residential use
60dB
50dB

Input Limit Values

Territory use destination class Times of reference
Day
(6.00-22.00) 		Night
(22.00-6.00)
CLASS IV areas destined predominantly for residential use
65dB
55dB

Legislative Decree DPCM dated 14/11/97 daytime and nighttime maximum noise exposure limits in living environments and specifically:

Territory use destination class Times of reference
Day
(6.00-22.00) 		Night
(22.00-6.00)
Living areas with windows open
50dB
40dB

Legislative Decree DPCM dated 14/11/97 daytime and nighttime maximum noise exposure limits in living environments and specifically:

Territory use destination class Times of reference
Day
(6.00-22.00) 		Night
(22.00-6.00)
Living areas with windows closed
35dB
25dB
Solution

After the inspection, 2 Zeta engineers identified and presented the customer with the most appropriate solution, identified as an acoustic barrier, presenting a project description, the intervention and a calculation of the necessary economic investment.

The peculiarity of the barrier identified as a solution is that it is 26m high from the ground floor.

After a careful structural, static and wind pressure calculation to verify the stresses that the barrier can undergo, a solid and robust, time-resistant structure has been installed to support the weight of the panels and the stresses.

Paneling with a thickness of 100 mm was chosen, with diversified density to adequately absorb the sound waves.

Results

The acoustic barrier has reached the goal of satisfying the limits set by the Legislative Decree D.P.C.M. dated 14/11/97

-12dB

We have achieved compliance with the zoning limits of the City of Milan for night emissions of 50 dB(A)