We are constantly detecting sounds. Even when you assume that it is completely silent, in most cases there will be some form of background noise that may not be detected by your human ear. Sounds are in fact pressure variations and travel in the form of sound waves that flow through mediums such as solids, fluids, or air.
The way in which an ear hears involves first detecting and then amplifying vibrations, followed by converting the vibrations into electrical signals which are then interpreted in your auditory cortex. The measurement for sound is decibels, and our abilities to hear forms a part of the five senses, which is important for functioning. Your ability to hear is what helps to keep you safe and even brings you pleasure and joy, but when overloaded which comes from sensory input from noise pollution, your senses can experience overload which leads to ill health and stress. This is why it is very important to take the necessary measures to control the noises in the homes or buildings that we work or live in.
What Is Structure Borne Sound?
“Structure Borne” is described as a transmission medium. Opposite to the vibrations which flow through the air, a structure-borne sound travels through any solid materials like steel, concrete, and wood, and in the most basic terms, it is applied to the noises that are generated inside a building. Examples of these sounds include the heavy footsteps that come from a neighbour upstairs, or the sound of a door that slams. The heavy footsteps are what caused vibrations within the floor structure, which then direct both downward and upward through the ceiling.
5 Processes Involved In Structure Borne Sound
When structure-borne sound is generated and transmitted it is divided up into five distinct processes:
- Generation: This involves the oscillation source.
- Transmission:Transfer of oscillatory-energy to a building structure that is derived from the actual source.
- Propagation: A mechanism that involves how the energy distributes through the overall structure.
- Attenuation: As sound waves flow through a structure they reflect partially off certain surfaces, which reduces their energy, and diminishes the sound.
- Radiation: Emission of sounds that come off exposed surfaces, which results in both structure-borne sound and airborne sound.
The Importance of Structure Borne Sound
In light of the fact that complaints about noise are the main cause of neighbour disputes according to a noise survey in London, along with the damaging impact that unwanted noise often has on our daily well-being, it becomes important to take the risks involved in structure-borne sound into consideration when renovating or designing buildings. The Government’s Building Regulations Approved Document E “Resistance to the passage of sound” has set out the minimum standards when it comes to impact-sound insulation which covers between and within buildings. These standards include not only offices and homes, but also schools. The stringent criteria are focused on mitigating noise production inside structures.
How to Measure Structure Borne Sound
The impact-sound transmission will be measured in “situ” which involves a type of tapping machine that comes with steel-faced hammers, that are used to strike test surfaces. The sounds are then recorded and the decibel measurement is used, in an adjacent space. Yet this test does not take into account the several different noises that can be produced, which is why a series of measures are used in order to lower structure-borne sound.
Techniques Used to Reduce Structure Borne Sound
The way to lower structure-borne sound is to dampen or weaken the vibrations that are caused by the noise source. Below is a list of the methods that are used to mitigate production and transmission of structure-borne sound:
- Padding and carpets – Laminate or wooden floors may look great, yet they are one of the main culprits when it comes to creating significant amounts of structure-borne noise. Carpets are a better solution when possible.
- Resilient underlay – Typically manufactured from rigid fibreglass or recycled foam or rubber, this is a material type that performs in the same way as padding and carpets.
- Soundproofing compounds – Usually installed between two rigid structures like sub-flooring, the soundproofing compounds are able to dissipate vibrations when moving through the structure.
- Create a gap -One of the easiest ways to lower structure-borne sound is when there is a solid-structure, followed by an air-gap, and then another solid structure. By breaking up the contact between these masses in the way if installing raised floors, suspended ceilings, and secondary-wall structures, it helps to reduce transmission of sound waves and to break contact. In a similar way, the high-mass constructions deploy an offset construction or incorporate cavities to prevent these transmissions.
- Install anti-vibration solutions – Spring-ceiling hangers, sound clips, and anti-vibration mounts are all useful in dampening structure-borne noises.