In our daily lives, we are constantly surrounded by sound, even in moments of apparent silence. Although we may not perceive it, there is always a background noise present. Sound is essentially fluctuations in pressure that propagate as sound waves through various mediums like air, fluids, or solids. Our ability to hear relies on our ability to detect and amplify these vibrations, which are then converted into electrical signals and interpreted by the auditory cortex. Hearing, Measured in decibels, is one of our primary senses and plays a crucial role in our daily experiences. It ensures our safety and brings us happiness, but the presence of excessive unwanted noise can overload our senses, leading to stress and negative impacts on our well-being. That’s why it is vital to effectively manage and control noise within the buildings where we live and work.
What Does Structure Borne Sound Refer to?
The distinguishing factor of a sound being considered “structure borne” is primarily the medium through which it travels. Unlike vibrations that propagate through the air, structure-borne sounds propagate through solid materials like wood, concrete, and steel. In simpler terms, this pertains to the generation of noise within buildings. Instances of structure-borne sound, or structure-borne noise, include the sound of heavy footsteps from an upstairs neighbour or the noise produced by a slamming door. These heavy footsteps create vibrations within the floor structure, which propagate both upwards and downwards through the ceiling.
The Five Methods of Transmitting Vibration-Induced Sound
The process of producing and conveying structure-borne sound can be categorized into five separate stages.
- The origin of the oscillation is referred to as generation.
- Transmission refers to the process of transferring the oscillatory energy from its source to the building structure.
- Propagation refers to the process through which the energy is evenly distributed throughout the entire structure.
- Attenuation refers to the process in which sound waves travelling through a structure are partially reflected by surfaces, resulting in a decrease in their energy and the reduction of sound.
- Radiation refers to the release of sound from a surface that is exposed, resulting in the generation of both structure-borne and airborne sound
What is the Significance of Structure Borne Sound?
Given that noise grievances are the primary catalyst for conflicts between neighbours, as well as the negative effects that undesirable noise can have on our overall well-being, it is crucial to thoroughly deliberate on the potential hazard of structure-borne sound during the process of designing and renovating buildings. In fact, the Government’s Building Regulations Approved Document EE, which focuses on “Resistance to the passage of sound,” establishes the minimum standards for sound insulation caused by impact both within and between various types of buildings. These regulations encompass not only residential and office spaces but also educational institutions. The precise requirements outlined in this document aim to mitigate the generation of noise within the building’s structure itself.
Controlling structure-borne sound is a crucial factor to consider in delicate building structures, like recording studios, where the aim is to minimize external noise as much as possible.
What is the Process for Measuring Structure-Borne Sound?
Sound transmission impact is assessed on-site by employing a tapping device equipped with steel hammers to strike the surface being tested. The resulting sound is recorded and quantified in decibels in the surrounding area. Nonetheless, it is important to note that this method does not account for the diverse array of noises that may be generated. Therefore, multiple strategies are implemented to mitigate the propagation of sound through the structure. One such effective strategy that has gained popularity for reducing sound transmission is the use of cavity wall soundproofing foam, which can be instrumental in minimising structure-borne sound in various settings.
Techniques for Minimizing Structure-Borne Noise
To minimize structure-borne sound, it is essential to attenuate or dampen the vibrations resulting from the noise source. Below are the techniques utilized to mitigate the generation of structure-borne sound.
- Carpets and padding – While wooden or laminate floors may be visually appealing, they can generate significant structure-borne noise. Therefore, it is advisable to utilize carpets whenever feasible.
- Typically composed of sturdy fibreglass, recycled rubber, or foam, resilient underlays function similarly to carpets and padding.