Impact sound
Sound is transmitted in buildings by both air-borne sound and structure-borne sound.
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.
Impact sound can be a form of noise nuisance, particularly in dwellings, and can contribute to health problems, such as:
- 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.
Building Regulations Approved Document E - 'Resistance to the passage of sound' sets minimum standards for 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.
[edit] 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.
- Part E compliance.
- Reverberation time.
- Room acoustics.
- Sound absorption.
- Sound frequency.
- Sound insulation.
- Sound insulation testing.
- Sound reduction index (SRI).
- Sound v noise.
- Structure-borne sound.
- Underlay.
Featured articles and news
Or are you capping.
STEM ambassadors needed for ICE CityZen award.
Digital gaming competition for UK students aged 16 to 18.
Heritage protection in England vs Australia.
Fire doors and the Fire Door Inspection Scheme.
Three-quarters of fire doors fail inspections
UN International Day for Biological Diversity, May 22.
The role of geoparks, biospheres and world heritage sites.
BSRIA conference 2022, June 23.
Just one month to go ! Find out more here.
Restoring Broadbent’s Bath House
A new gallery for the University of Huddersfield.
Corruption in the construction industry.
What will it take to stop it ?
To celebrate world bee day 2022 !
Just one month until the changes to part L come into effect.
Not forgetting part F and the new part overheating part O.
Heat Pump demand rises by one quarter.
As energy prices jump up in cost.
With people in the UK from Ukraine.
Industry leader Steve Murray takes on role.
An abundant and versatile building material.
How overheating complicates ending gas in the UK.
600,000 heat pump installations targeted per year by 2028.
Cost planning, control and related articles on DB.
Helping prevent those unwanted outcomes.
ICE debate Public transport - post pandemic.
How has transport changed due to Covid-19 ?
Cross-ventilation in buildings. Do you have it ?
Will you need it ? after June 15 and the new Part O ?
Share your knowledge with the industry.
Create an account and write the first of many articles.
The green jobs delivery group.
CIAT commentary after the first meeting.
Liverpool's world heritage site status
Who is to blame?
Research recommends focussing on portfolio success rather than project success.