Glossary

Absorption coefficient
A quantity characterising the effectiveness of a sound absorbing surface. The proportion of sound energy absorbed is given as a number between zero (for a fully reflective surface) and one (for a fully absorptive surface).

Absorptive material 
Material that absorbs sound

Airborne sound
Sound propagating through the air

Airborne Sound Insulation
Sound insulation that reduces transmission of airborne sound between buildings or parts of buildings.


ANC
The Association of Noise Consultants, who are an accreditation body specifically for organisations who carryout Pre completion sound insulation testing.
ANC accredited tester Minimum qualification status for an individual who carries out pre completion sound insulation testing.


Audiometry
Audiometry is the science of carrying out objective hearing tests on individuals to determine the acuity of their hearing. Acoustic Associates (Peterborough) are able to carry out audiometric testing as well as offering courses in audiometry.


BREEAM
Building Research Establishment Assessment Method. An environmental assessment method and rating system for buildings. Acoustic Associates (Peterborough) are experienced with assessing acoustic aspects of building design and performance with respect to BREEAM advice and criteria.


British Standard BS 4142
A standard used for assessing the noise impact of development in mixed use industrial/residential areas. Acoustic Associates (Peterborough) have used BS BS4142 to assess noise in many different situations since the standard was first introduced in 1996.


British Standard BS 8233
A design standard for assessing the acoustic performance of buildings. We use guidance for the standard for assessing  for example whether noise levels in dwellings rooms are reasonable.

Caulking
Process of sealing joints.

Cavity Stop
A proprietary product or material such as mineral wool used to close the gap in a cavity


Complaints
Noise complaints may be generated due to noise from a variety of sources. Generally Acoustic Associates (Peterborough) will be called in where complaints have been recorded over industrial noise or entertainment noise.


Calculation of Road Traffic Noise (CTRN)
This procedure allows us to impact the likely noise levels that residents (and others) may be exposed to from future road traffic. Acoustic Associates (Peterborough) use this, and other methods), to predict road traffic noise.


Compliance Testing
BRREAM, BB93, HTM08-01 and other documents specify acoustic criteria which must be met. These can often be verified by a competent person carrying out sound tests. 

Ctr
The correction to a sound insulation quantity (such as DnT,W ) to take account of a specific sound spectrum. See BS EN ISO 717-1:1997


Decibel (dB)
The unit used for many acoustic quantities to indicate the level with respect to a reference level.


Design Study
Architects (and others) require robust design advice in the field of acoustics, generally to ensure that their designs will comply with the requirements of Document E with respect to sound insulation, but also to address other acoustic issues which arise in schools hospitals and offices. Acoustic Associates (Peterborough)’s design study service aims to meet that requirement buy offering useful anaylysis and advice for our clients,

DnT
The difference in sound level between a pair of rooms, in a stated frequency band, corrected for the reverberation time. See BS EN ISO 140-4:1998.


DnT,W
A single-number quantity which characterizes the air sound insulation between rooms. See BS EN ISO 717-1:1997.

DnT,W + Ctr
A single-number quantity which characterizes the air sound insulation between rooms using noise spectrum no 2 as defined in BS EN ISO 717-1:1997. See BS EN ISO 717-1:1997.


Environmental Noise
This is noise from external sources such as industry or traffic(road, rail or air) which may cause annoyance to someone at their workplace or in their dwelling. Acoustic Associates have extensive experience in addressing environmental noise issues.


Environmental Vibration
This is vibration from external sources such as industry or traffic (road, rail or air) which may cause annoyance to someone at their workplace or in their dwelling or damage to their building . Acoustic Associates have extensive experience in addressing environmental noise issues.


Flanking transmission
Sound transmitted between rooms via flanking elements instead of directly through separating elements or along any path other than the direct path.


Floating floor
A floating floor consists of a floating layer and resilient layer.


Groundborne vibration
Vibration  transmitted through the ground. Typically Acoustic Associates (Peterborough) have experience of measuring and assessing vibration from sources such as trench digging, piling, HGV traffic and rail traffic.


Hand arm vibration
Hand Arm Vibration transmitted into a workers’ hands and arms. Due to the health risks of hand arm vibration, there are Regulations which employers are expected to adopt (the 2005 Control of Vibration at Work Regulations). We are able to offer assessments at your workplace in hand arm vibration in accordance with these regulations. In addition we offer courses, generally 3 days in duration, which will qualify delegates as competent persons who can carry out hand arm vibration assessment themselves.


IOA 
The Institute of Acoustics.

Impact sound
Sound resulting from direct impact on a building element.

Impact sound insulation 
Sound insulation which reduces impact transmission from direct impacts such as footsteps on a building element. Impact tests are usually conducted on a separating floor.

Independent ceiling
A ceiling which is fixed independently of a separating floor or an internal floor.

Internal floor
Any floor that is not a separating floor

Intermediate landing
A landing between two floors

Internal wall
Any wall that does not have a separating function. T

L’nT
The impact sound pressure level in a stated frequency band, corrected for the reverberation time. See BS EN ISO 140-7:1998


L’nT,w
A single number quantity used to characterise the impact sound insulation of floors. See BS EN ISO 717-2:1997.

Mass per unit area
Is expressed in terms of kilograms per square metre (kg/m2).

Mid-Frequency Reverberation Time
The average reverberation time across the 500Hz, 1kHz and 2 kHz octave frequency bands.


New Build and Refurbishments
More onerous acoustic criteria may apply for newly built properties than for existing buildings which are being refurbished. For example, Document E of the building regulations requires that a separating wall in a newly built property should achieve a DnT,w + Ctr or 45 dB, though only 43 dB for a refurbished property.


Noise 
Unwanted sound.


noise control
This the acoustic science of reducing noise emissions from a source to a receiver and is an area in which Acoustic Associates (Peterborough) offer expert guidance. In particular our advice on noise control is useful when tackling noise which employees are exposed to in a working day. Reducing environmental noise emissions from industrial sources or traffic (road, rail and air)


Planning Applications
Planning Applications to local authorities are required for most development in the UK.  Acoustic Associates (Peterborough) are experienced in advising client on how to achieve the acoustic criteria which needed to be met for planning applications.


Planning Conditions
Planning Conditions may be applied to certain developments and we have expertise in those which have an acoustic aspect. We offer consultancy on the framing of planning
conditions and in the past we have helped our clients contest unreasonable conditions which have been imposed upon them.


Planning Policy Framework
The National Planning Policy Framework sets out the Government’s planning policies for England and how these are expected to be applied. Its introduction has significantly impacted the consequences for those undertaking acoustic work as part of the planning process.

Resilient layer
A layer that isolates a floating layer from a base floor and surrounding walls.


Reverberation
The persistence of sound in a space (room) after a sound source has stopped.


Reverberation Time
The time, in seconds, taken for the sound to decay by 60dB after a sound source has been stopped. The reveberation time of the room can effect a rooms uiltlity. For instance rooms with a high reverberation time may be suitable for music but not for lecturing.

 

Speech Transmission Index (STI)
The performance standard for speech intelligibility in open plan teaching spaces. Required values between 0.6 and 1.00.

Rw
The weighted Sound Reduction Index, which is measured in the laboratory.

RASTI
Rapid Speech Transmission Index just considers the 500Hz and 2kHz octave bands.


Sound Insulation 
The sound insulation of a wall or floor refers to  its ability to resist the passage of sound.

 


Training 
Acoustic Associates (Peterborough) are able to offer training in all areas of acoustics and vibration


Vibration
Vibration is a mechanical phenomenon whereby oscillations occur about an equilibrium point. The oscillations may be periodic such as the motion of a grinder or random such as the movement of a vehicle on a bumpy road. It may or may not be a desirable phenonemon, though Acoustic Associates (Peterborough) generally become involved when it is not so.


vibration control
This the acoustic science of reducing vibration emissions from a source to a receiver and is an area in which Acoustic Associates (Peterborough) offer expert guidance. In particular our advice on noise control is useful when tackling vibration which employees are exposed to in a working day
Reducing environmental vibration emissions from activities such as piling.


whole body vibration
Whole Body vibration is vibration transmitted into a workers’ body. Due to the health risks of whole body vibration, there are Regulations which employers are expected to comply with i.e. the 2005 Control of Vibration at Work Regulations. We are able to offer assessments at your workplace in whole body vibration in accordance with these regulations. In addition we offer courses, generally 3 days in duration, which will qualify delegates as competent persons who can carry out whole body vibration assessment themselves.

World Health Organisation (WHO)
The WHO have published a document “Guidelines for Community Noise” which is often referred to by acousticians. It includes guideline levels for noise inside and outside dwellings which Acoustic Associates (Peterborough) often refer to in our noise assessments.

Workplace Noise (Occupational Noise)
This is noise which employees are exposed to whilst undergoing typical duties.  Due to the health risks of workplace noise there are Regulations which employers are expected to comply with i.e. the 2005 Control of Noise at Work Regulations. We are able to offer assessments at your workplace in noise in accordance with these regulations. In addition we offer courses, generally 3 days in duration, which will qualify delegates as competent persons who can carry out control of noise at work assessments themselves.