One must always consider structure-borne sound whenever they are planning to install sound insulation measures in newly-constructed buildings. But, what is structure-borne sound, and what are necessary measures to reduce it?
What Is Structure-borne Sound?
In its simple form, the sound is produced from pulses and travels through a particular medium like air or solid structures to reach receptors like ears or detection devices.
In essence, you can expect the air in a building or its physical structures that include walls and beams to transmit sound/noise to other occupants in the building. The type of sound that is carried through a building’s structures is referred to as structure-borne sound, according to the British Regulations Approved Document E.
For example, occupants in an upper building floor can cause noise/sound that reaches the floor immediately below. Common sources of such sound may include the stomping of feet or pulling/pushing of furniture on the floor. The sound that is audible across the walls or floors of a building is considered a structure-borne sound.
In terms of technical differentiation, structure-borne sound can be divided into five groups. They are:
- Generation: refers to the real source of oscillation. Describes where the oscillation is originating from.
- Transmission: refers to the transfer of the oscillation’s energy from its originating source to the building.
- Propagation: refers to the mechanism that transmits oscillation’s energy to all parts of the building’s structures.
- Attenuation: refers to the reduction of sound amplitude and intensity as the sound waves are reflected or bounced off the surfaces of a building’s structures. Simply put, attenuation reduces the sound’s impact.
- Radiation: refers to the production of sound vibrations from exposed surfaces. At the fundamental level, both airborne and structure-borne sound are related. This is because sound vibrations that bounce from the solid surfaces in a building form airborne sound.
In addition, airborne sound can cause sections of the building to vibrate when these sound waves come up against unprotected building surfaces.
How Can Structure-borne Sound Be Reduced?
The impact of structure-borne sound can be lessened in the following ways:
• Consider installing carpets and paddling to help absorb sound waves.
• Where possible, use a strong underlay made of foam, recycled rubber, and firm fiberglass to reduce/eliminate structure-borne sound.
• Where befitting, install sound clips, spring ceiling hangers, and resilient mounts.
• When dealing with housing structures such as subflooring, consider applying soundproofing compounds between two rigid components/surfaces. The work of this compound is to distribute vibrations generated by sound waves as they move around the building structure.
• Other ways to reduce structure-borne sound are to use a secondary walling structure, a raised floor, and a suspended ceiling system.
• Also consider using high-mass structures with cavities or offset construction to avoid transmission of vibrations.
Using suitable building design features is an effective technique of mitigating structure-borne sound. However, it is a very complex subject. This is because the structure-borne sound is determined by several factors like the structural composition, nature, and construction of the receiving spaces and radiating surfaces. If you are wanting to do a vibration survey and are based in the London area then take a look at vibration survey in London.
It is best to consult an acoustic expert when designing building structures with sound-proofing requirements.
Minimum Standard Required For Insulation Of Impact Sound
The Building Regulations Approved Document E (also quoted earlier in this article) provides for the least acceptable requirements for noise insulation. The structure’s impact sound transmission must be measured and tested by allowing a tapping machine to strike a surface for sound to be received from an adjacent building space. That way, the correct measure of the structure-borne sound impact can be established.
Five Processes For Structure-borne Sound
Generation: refers to the origin and source of an oscillation.
Transmission: this is the movement of the oscillatory energy from its source towards the structure.
Propagation: refers to the spreading out of oscillatory energy all through a building’s structure.
Attenuation: This is the reduction of sound impact when sound waves traveling through a building structure come upon structural or material changes; the waves are reflected thus reducing their energy. Accordingly, the sound is attenuated.
Radiation: refers to the production of sound from exposed surfaces.
Often, many people consider airborne sound separate from structure-borne sound. However, they are closely connected. The airborne sound may be created when vibrations radiate from surfaces. When this airborne sound encounters a surface, it may cause a section of the building to vibrate.