- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 12 Apr 2018
To help develop this article, click ‘Edit this article’ above.
Impact sound (or impact noise) is a form of structure-borne sound that occurs when an object impacts on another, resulting in the generation and transmission of sound. The structural vibration caused by the impact results in sound being radiated from an adjacent vibrating surface. NB structure-borne sound may also be generated by vibrating sources rather than impact sources.
A typical example of an impact sound is footsteps on a floor resulting in sound being transmitted through the floor construction and heard in the space below. Impact sound can travel through solid structures and through cavities.
- Tension or anxiety.
- Decreased performance.
- Reduced productivity.
- Eardrum damage or hearing difficulties.
- Increased blood pressure or stress levels.
- Psychological damage.
The occurrence of impact sound is dependent on a range of factors, including:
- The force of impact.
- The characteristics of the surface that is impacted upon.
- The characteristics of the structure through which the vibration transmits.
- The characteristics of the radiating surface.
Impact sound can be prevented or reduced by:
- Carpets and pads – soft carpets and thick pad cushions can be particularly effective at reducing middle to high level frequencies, although they are less effective at isolating low frequency sound. It is important to consider whether carpets or pads might be removed in the future.
- Resilient underlay – can have a similar effect to carpets and pads. Generally, they are made from recycled rubber, rigid fibreglass, foam or other such materials. They absorb, or isolate impact energy and can be effective in minimising impact sound at middle to high level frequencies. If the underlay has significant mass, it may also provide sound insulation from air-borne sound.
- Resilient mounts – hanging resilient mounts, sound clips or spring ceiling hangers can reduce the transmission of impact sound.
- Soundproofing compounds – applying sound proofing layers can be effective in reducing impact sound. Typically the compound is applied between two rigid materials, such as subflooring. The compound dissipates the vibrations caused by sound waves as they move through the structure, and can reduce sound at all frequencies.
- A suspended ceiling system or raised floors can be used to improve impact sound insulation.
Impact sound transmission is typically measured in-situ with a tapping machine which uses steel-faced hammers to strike a test surface and generate sound in an adjacent space which can be recorded or monitored. This is useful only in giving an indication of the likely level of impact sound as it does not accurately represent the variety of impacts that might be experienced in practice.
 Related articles on Designing Buildings Wiki
- Airborne sound.
- Ash deafening.
- Audio frequency.
- British standards.
- Building acoustics.
- Building Bulletin 93: acoustic design of schools.
- Building regulations.
- Flanking sound.
- Noise nuisance.
- Reverberation time.
- Sound absorption.
- Sound frequency.
- Sound insulation.
- Sound reduction index (SRI).
- Sound v noise.
- Structure-borne sound.
Featured articles and news
HAB is a bridge design concept which incorporates an integrated hydraulic system in order to carry more weight.
ICE publish a discussion paper looking at the role of the engineer in creating inclusive cities.
A PQP describes the activities, standards, tools and processes necessary to achieve quality in a project's delivery.
How Lidl has been actively working to reinforce their brand through sustainability.
Association of British Insurers describe full-scale cladding tests as 'utterly inadequate'.
This article examines the changing policy commitments and evolving definitions of the zero carbon home.
Researchers believe they may have created a 'game-changing' new form of concrete using graphene.
Grouting refers to the injection of materials into a soil or rock formation to change its physical characteristics.
Part of Designing Buildings Wiki, BREEAM Wiki will advance knowledge sharing for the BRE family of sustainability tools.
From the decorative to the utilitarian, and from the photographed to the forgotten.
New BRE book considers the progression from project-based knowledge creation to whole-life urban knowledge management.
This CIOB article explores the concept of value in building design and construction.