What limits must the noise emissions generated by the operation of electromechanical systems serving a building comply with?
The law distinguishes between the noise that impacts on people who live inside the same building in which the systems are located and on people who live in other buildings, regardless of the internal or external location of the systems themselves. For people who live inside the building in which the systems are located, the Prime Ministerial Decree of 5/12/97 sets limits distinguishing between systems with discontinuous operation (hydraulic drains, elevators, etc..., with limits of 35 dB(A)) and continuous (ventilation systems, air conditioning, etc..., with limits varying from 25 to 35 dB(A) depending on the intended use of the building).
For people who live outside the building in which the systems are located, the Prime Ministerial Decree of 14/11/97 sets absolute limits and differentials that vary between day and night. That is, it sets both the maximum values to be respected (day or night), divided into 6 types of zones into which the national territory is fragmented, and differentials, i.e. the difference in noise between the system on and off cannot exceed 5 dB (A) during the day and 3 dB(A) at night (from 10pm to 6am).
Who are the parties responsible for any exceeding of the legal limits?
The parties responsible for exceeding the legal limits are the system designer, the installer and the seller. It is underlined that failure to comply with the legal limits is a crime, i.e. it is criminal.
How to protect yourself?
By relying on a specialist engineer known as a "Competent Technician in Environmental Acoustics" who is able to predict or measure (depending on the case) the sound pressure levels induced by the operation of the systems in living environments (including offices, schools, hospitals are living environments, i.e. inhabited by humans) to be protected and implemented through specific planning all those measures aimed at containing the noise emissions of the systems within the limits of the law; or to draw up a noise impact assessment.
How to contain sound propagation from systems?
First of all, a distinction must be made between airborne and structural sound propagation. In this discussion we will deal with the first and provide brief indications for the second.
Airborne transmission
Airborne propagation is that sound emission which propagates in the air and which, by virtue of its power and frequency, can even pass through walls of considerable thickness and which can therefore reach the environments adjacent to the technical room in which it is installed the system or which is transmitted through the air duct system to the living spaces.
Wanting to provide a summary of the interventions that can be implemented to reduce the component of noise that propagates through the air, it is first necessary to distinguish between systems installed in an internal environment (technical room) and in an external environment (typically building roofs).
For systems installed indoors you can:
1. act on the source of noise, i.e. on the system. In the case of a new installation, providing systems with a sound power rating ("Lw") certified by a third party authorized by Accredia that is as low as possible and in the case of existing systems, providing appropriate sound mitigation systems such as cabins, baffles, caps and grilles. aphonic type.
2. act on the casing of the technical room by providing:
- walls and floors equipped with high resistance to the passage of airborne noise (Rw > 60 dB);
- internally covering the walls and ceiling with fire-resistant sound-absorbing materials;
- the installation of appropriately calibrated soundproof external air intake grilles;
- doors and windows equipped with high resistance (sound impedance) to the passage of airborne noise.
3. act on the air intake and delivery channels by installing silencers and frequency-silenced channels according to the calculated needs and which cause the minimum loss of head.
For systems installed outdoors, what is stated in points 1 and 3 applies and the machine must also be CE14/2000 certified which regulates noise emissions from machines operating outdoors (implemented in Italy).
Structural transmission
Structural sound propagation, on the other hand, concerns the dynamic excitation transmitted to the structures on which the systems and their ducts cling or rest. It is fought by separating the different components of the system from each other and by suspending the attachments of the system to the civil structure on appropriately calibrated elastic springs.
Regarding the installation of systems operating both outdoors and in closed environments, including shafts or underground spaces, every mechanical system, more or less, is noisy. Furthermore, its noise level varies over time both because its workload can vary and because, frequently, the noise-reducing enclosures and anti-vibration supports deteriorate over time. But the question is: are there any limits to noise emissions that must be respected? Certainly yes and, I add, failure to comply is a crime, that is, it is criminal. But let's review the matter in order. Fundamentally, the law distinguishes between the noise generated by systems inside the building and the noise generated by external systems. First of all we deal with the noise generated by systems inside the building. Since 1997, state law has set very precise and distinct limits between discontinuous (with limits of 35 dB(A)) and continuous (with limits varying from 25 to 35 dB(A) depending on the intended use use of the building). The parties responsible for exceeding the legal limits are the designer of the system understood as the set of all the components that it was decided to install in the specific context, assuming there is one, the installer and the seller of the same; essentially everyone except the client.
Therefore, in order to avoid many problems that cause waste of time and money, it is at least strongly advisable to verify that there is an "Acoustic Evaluation" drawn up by an engineer who is a "Competent Technician in Acoustics" pursuant to law 447/95 which precisely provides the sonic impact that a system, however simple, can have. In this way the liability of the installer is attenuated since, in any case, if the judge finds negligence on the part of the installer he would in any case have responsibilities. It is specified that third parties who suffer from noise emissions can also be the owners of the system: for example a condominium chiller which annoys the condominiums themselves both due to the propagation of sound by air and by structure.
How to contain sound propagation? It is approached with two different methods relating to airborne and structural sound propagation. Airborne propagation is that sound emission that propagates in the air and which, by virtue of its power and frequency, can pass through even walls of considerable thickness. It is fought primarily by installing systems with a sound power rating (“Lw”) certified by an Accredia-authorised third party which is as low as possible; it will then be essential to rely on an acoustic engineer to calculate how and to what extent this sound power can pass through walls and attics and thus enter neighboring apartments, offices, hotel or hospital rooms. Structural sound propagation, on the other hand, concerns the dynamic excitation transmitted to the structure on which the systems and their ducts cling or rest. It is fought by separating the different components of the system from each other and by suspending the attachments of the system to the civil structure on appropriately calibrated elastic springs. The so-called "anti-vibration feet", made of rubber, are a very ineffective palliative while only by studying the way the machine vibrates is it possible to design adequately effective elastic suspensions (on springs). In summary, to reduce his burden of responsibility, the installer of the systems must seek advice from a specialist engineer.
If, however, the system in question was installed outdoors (typically on the roof of the building) then in addition to what has just been said here, the problem must also be considered from a different aspect which starts from the legislative framework. Since 1991, state law has set very precise limits: these limits, which vary between day and night (where they are more severe) are both absolute and differential. There are therefore both maximum values to be respected (day or night), divided into 6 types of zones into which the national territory is fragmented, and of a differential type, i.e. the difference in noise between the system on and off (where perhaps I hear traffic noise only) cannot exceed 5 dB(A) during the day and 3 dB(A) at night. Here, for example, installing a system that works 24 hours a day presents more risks than one that only operates during the day (the day goes from 6 am to 10 pm) as does installing a banal condensing unit on the internal courtyard of an apartment building (typically quieter than the front facade road) may cause the legal limits to be exceeded. I often hear myself making the observation that the machine is certified, since it complies with CE14/2000 which regulates the noise emissions of machines operating outdoors (implemented in Italy): well this has no relevance since the machine itself is CE14/2000 certified it may be adequate in one location and inadequate in another.
Also in this case, the parties responsible for exceeding the legal limits are the designer of the system (assuming there is one), the installer and the seller of the same; essentially everyone except the client. Therefore it is necessary to draw up a "Forecast acoustic impact assessment" signed by an engineer who is a "Competent Technician in Acoustics" pursuant to law 447/95 which predicts the sound impact that a system, however simple, may have and plans any mitigation works. In this way the liability of the installer is attenuated since, in any case, if the judge finds negligence on the part of the installer he would in any case have responsibilities.
In this regard, we cite the Sentence of the Court of Cassation n. 39883/2017 which condemned the owner of an air conditioner (who then has the right to take action against the person who installed and sold it) because its noise disturbance caused biological damage to the neighborhood (difficulty in falling asleep). Finally, it is specified that third parties who suffer from noise emissions can also be the owners of the system: for example a condominium air conditioner which annoys the condominiums themselves both due to the propagation of sound by air and by structure.
What limits must the noise emissions generated by the operation of electromechanical systems serving a building comply with?
The law distinguishes between the noise that impacts on people who live inside the same building in which the systems are located and on people who live in other buildings, regardless of the internal or external location of the systems themselves. For people who live inside the building in which the systems are located, the Prime Ministerial Decree of 5/12/97 sets limits distinguishing between systems with discontinuous operation (hydraulic drains, elevators, etc..., with limits of 35 dB(A)) and continuous (ventilation systems, air conditioning, etc..., with limits varying from 25 to 35 dB(A) depending on the intended use of the building).
For people who live outside the building in which the systems are located, the Prime Ministerial Decree of 14/11/97 sets absolute limits and differentials that vary between day and night. That is, it sets both the maximum values to be respected (day or night), divided into 6 types of zones into which the national territory is fragmented, and differentials, i.e. the difference in noise between the system on and off cannot exceed 5 dB (A) during the day and 3 dB(A) at night (from 10pm to 6am).
Who are the parties responsible for any exceeding of the legal limits?
The parties responsible for exceeding the legal limits are the system designer, the installer and the seller. It is underlined that failure to comply with the legal limits is a crime, i.e. it is criminal.
How to protect yourself?
By relying on a specialist engineer known as a "Competent Technician in Environmental Acoustics" who is able to predict or measure (depending on the case) the sound pressure levels induced by the operation of the systems in living environments (including offices, schools, hospitals are living environments, i.e. inhabited by humans) to be protected and implemented through specific planning all those measures aimed at containing the noise emissions of the systems within the limits of the law; or to draw up a noise impact assessment.
How to contain sound propagation from systems?
First of all, a distinction must be made between airborne and structural sound propagation. In this discussion we will deal with the first and provide brief indications for the second.
Airborne transmission
Airborne propagation is that sound emission which propagates in the air and which, by virtue of its power and frequency, can even pass through walls of considerable thickness and which can therefore reach the environments adjacent to the technical room in which it is installed the system or which is transmitted through the air duct system to the living spaces.
Wanting to provide a summary of the interventions that can be implemented to reduce the component of noise that propagates through the air, it is first necessary to distinguish between systems installed in an internal environment (technical room) and in an external environment (typically building roofs).
For systems installed indoors you can:
1. act on the source of noise, i.e. on the system. In the case of a new installation, providing systems with a sound power rating ("Lw") certified by a third party authorized by Accredia that is as low as possible and in the case of existing systems, providing appropriate sound mitigation systems such as cabins, baffles, caps and grilles. aphonic type.
2. act on the casing of the technical room by providing:
- walls and floors equipped with high resistance to the passage of airborne noise (Rw > 60 dB);
- internally covering the walls and ceiling with fire-resistant sound-absorbing materials;
- the installation of appropriately calibrated soundproof external air intake grilles;
- doors and windows equipped with high resistance (sound impedance) to the passage of airborne noise.
3. act on the air intake and delivery channels by installing silencers and frequency-silenced channels according to the calculated needs and which cause the minimum loss of head.
For systems installed outdoors, what is stated in points 1 and 3 applies and the machine must also be CE14/2000 certified which regulates noise emissions from machines operating outdoors (implemented in Italy).
Structural transmission
Structural sound propagation, on the other hand, concerns the dynamic excitation transmitted to the structures on which the systems and their ducts cling or rest. It is fought by separating the different components of the system from each other and by suspending the attachments of the system to the civil structure on appropriately calibrated elastic springs.
Regarding the installation of systems operating both outdoors and in closed environments, including shafts or underground spaces, every mechanical system, more or less, is noisy. Furthermore, its noise level varies over time both because its workload can vary and because, frequently, the noise-reducing enclosures and anti-vibration supports deteriorate over time. But the question is: are there any limits to noise emissions that must be respected? Certainly yes and, I add, failure to comply is a crime, that is, it is criminal. But let's review the matter in order. Fundamentally, the law distinguishes between the noise generated by systems inside the building and the noise generated by external systems. First of all we deal with the noise generated by systems inside the building. Since 1997, state law has set very precise and distinct limits between discontinuous (with limits of 35 dB(A)) and continuous (with limits varying from 25 to 35 dB(A) depending on the intended use use of the building). The parties responsible for exceeding the legal limits are the designer of the system understood as the set of all the components that it was decided to install in the specific context, assuming there is one, the installer and the seller of the same; essentially everyone except the client.
Therefore, in order to avoid many problems that cause waste of time and money, it is at least strongly advisable to verify that there is an "Acoustic Evaluation" drawn up by an engineer who is a "Competent Technician in Acoustics" pursuant to law 447/95 which precisely provides the sonic impact that a system, however simple, can have. In this way the liability of the installer is attenuated since, in any case, if the judge finds negligence on the part of the installer he would in any case have responsibilities. It is specified that third parties who suffer from noise emissions can also be the owners of the system: for example a condominium chiller which annoys the condominiums themselves both due to the propagation of sound by air and by structure.
How to contain sound propagation? It is approached with two different methods relating to airborne and structural sound propagation. Airborne propagation is that sound emission that propagates in the air and which, by virtue of its power and frequency, can pass through even walls of considerable thickness. It is fought primarily by installing systems with a sound power rating (“Lw”) certified by an Accredia-authorised third party which is as low as possible; it will then be essential to rely on an acoustic engineer to calculate how and to what extent this sound power can pass through walls and attics and thus enter neighboring apartments, offices, hotel or hospital rooms. Structural sound propagation, on the other hand, concerns the dynamic excitation transmitted to the structure on which the systems and their ducts cling or rest. It is fought by separating the different components of the system from each other and by suspending the attachments of the system to the civil structure on appropriately calibrated elastic springs. The so-called "anti-vibration feet", made of rubber, are a very ineffective palliative while only by studying the way the machine vibrates is it possible to design adequately effective elastic suspensions (on springs). In summary, to reduce his burden of responsibility, the installer of the systems must seek advice from a specialist engineer.
If, however, the system in question was installed outdoors (typically on the roof of the building) then in addition to what has just been said here, the problem must also be considered from a different aspect which starts from the legislative framework. Since 1991, state law has set very precise limits: these limits, which vary between day and night (where they are more severe) are both absolute and differential. There are therefore both maximum values to be respected (day or night), divided into 6 types of zones into which the national territory is fragmented, and of a differential type, i.e. the difference in noise between the system on and off (where perhaps I hear traffic noise only) cannot exceed 5 dB(A) during the day and 3 dB(A) at night. Here, for example, installing a system that works 24 hours a day presents more risks than one that only operates during the day (the day goes from 6 am to 10 pm) as does installing a banal condensing unit on the internal courtyard of an apartment building (typically quieter than the front facade road) may cause the legal limits to be exceeded. I often hear myself making the observation that the machine is certified, since it complies with CE14/2000 which regulates the noise emissions of machines operating outdoors (implemented in Italy): well this has no relevance since the machine itself is CE14/2000 certified it may be adequate in one location and inadequate in another.
Also in this case, the parties responsible for exceeding the legal limits are the designer of the system (assuming there is one), the installer and the seller of the same; essentially everyone except the client. Therefore it is necessary to draw up a "Forecast acoustic impact assessment" signed by an engineer who is a "Competent Technician in Acoustics" pursuant to law 447/95 which predicts the sound impact that a system, however simple, may have and plans any mitigation works. In this way the liability of the installer is attenuated since, in any case, if the judge finds negligence on the part of the installer he would in any case have responsibilities.
In this regard, we cite the Sentence of the Court of Cassation n. 39883/2017 which condemned the owner of an air conditioner (who then has the right to take action against the person who installed and sold it) because its noise disturbance caused biological damage to the neighborhood (difficulty in falling asleep). Finally, it is specified that third parties who suffer from noise emissions can also be the owners of the system: for example a condominium air conditioner which annoys the condominiums themselves both due to the propagation of sound by air and by structure.