Acoustic Terminology M-S

Acoustic Terminology M-S

Our previous blog explained the  of acoustic terminology, this blog covers  M-S.

Mass

This is a physical quantity that expresses the amount of matter in a body. Walls and floors may be described in terms of the surface density (mass per unit area, kg/m2) of the wall face or the floor surface, which is the sum of the surface densities of each component of the construction. The density of materials is expressed as mass per unit volume, kg/m3, which can be provided via the core structure and linings such as in-situ concrete or solid dense block walls.

Mass per unit area (or surface density)

This is is expressed in terms of kilograms per square metre (kg/m2). This is often used to describe boards, panels, flooring and dry linings (see gypsum based board).

Resilience

This can reduce structural vibration transmission and still maintain material performance and overall dimensions, examples include floating floor treatments such as resilient battens or cradles, or resilient ceiling bars.

Resilient ceiling bars

This acoustic solution is generally metal based and vary in thickness from 11 mm to 30 mm. They are mounted perpendicular to the joist span direction and can increase both airborne and impact sound insulation. Care should be taken to ensure that the ceiling board fixings into the resilient bar do not come into contact with the joists and reduce the potential performance.

Resilient noggin

This is a small section of resilient ceiling bar which is used to assist in bracing non load bearing partitions.

Rw

This is a single-number quantity (weighted) which characterises the airborne sound insulation of a building element from measurements undertaken in a laboratory, in accordance with BS EN ISO 717-1: 1997

Sound Insulation Testing

Sound Insulation Testing is required near the end of a development to show that the performance of the party wall and floor partitions meet the standards as stipulated in Building Regulations Approved Document E. The testing methods for airborne and impact sound insulation is in full accordance with the suggested methods presented in BS EN ISO 140-parts 4 & 7: 1998.

Stiffness

This is can improve low frequency sound insulation, for example in floors, by reducing the potential for deflection or movement of the primary structure, therefore the correct spacing and depth of joists is important.

If your project requires some acoustic design input and/or sound insulation testing please don’t hesitate to contact us at info@aptsoundtesting.co.uk or call Darren direct on 07775623464 or visit our website at: www.aptsoundtesting.co.uk

Acoustic Terminology A-B

Acoustic Terminology A-B

Often confusion can arise from the large amount of ‘terms’ used in conjunction with acoustic design and sound insulation testing. To help with this we have made a list of the following terms along with a quick explanation:

 Absorption

This is the conversion of sound energy into heat, often by the use of a porous material.

Absorbent Material

This is a material that absorbs sound energy, such as acoustic mineral wool.

Airborne sound

This is sound which is propagated from a noise source through the medium of air. Examples of these are speech and sound from a television

Airborne Sound Transmission

This is direct transmission of airborne sound through walls or floors. When sound energy is created in a room, for instance by conversation, some of the energy is reflected or absorbed by room surfaces but some may set up vibrations in the walls and floor. Depending on both the amount of energy and the type of construction, this can result in sound being transmitted to adjacent parts of the building.

Air Path

This is a void in construction elements, which adversely affects the performance of sound resisting construction. Examples of air paths include incomplete mortar joints, porous building materials, gaps around pipes and shrinkage cracks – this can also effect the air tightness results.

 Bonded resilient cover

This is a thin resilient floor covering normally of minimum 3-5mm thickness, which is bonded to the isolated screed surface to reduce impact sound transmission such as footfall noise, however it has a lesser effect when it comes to airborne noise.

Acoustic_Site_Survey

If you have a project that requires acoustic design and/or sound testing please let us know. APT Sound Testing will ensure you will have direct contact with the allocated acoustician from the start of the process, through to the successful completion of the sound insulation testing.

If you would like more information in regards to acoustic services, please contact us at info@aptsoundtesting.co.uk or visit our website at: www.aptsoundtesting.co.uk