Why are Room Acoustics important?
Poor room acoustics can negatively impact the use of the space in question. Room acoustics is an integral part of building acoustic design.
Acoustic performance within a room can be affected by:
– Noise Break In from other rooms or external sources (sound insulation)
– Noise Break Out from the room to other rooms or externally (sound insulation)
– Reverberation, sound reflecting from hard surfaces within the space
– Mechanical noise from plant or equipment within the room
Poor acoustic design can cause the following health and well-being issues for the people using the room:
– Sleep deprivation
– Poor speech intelligibility
– Cognitive issues
– Stress and Anxiety
– Productivity issues
– Loss of revenue
Who does it affect?
Incorrectly designed or using spaces for the purposes they had not been intended for can result in poor room acoustics.
For areas requiring privacy it is necessary that the construction prevents sound from entering or leaving a space, by any means and can include walls, doors, glazing and air-conditioning ducts. Imagine having a consultation with your Doctor and then realising the people in the waiting room can hear the contents of your conversation.
Where speech intelligibility is a key requirement then the room needs to be designed with surfaces that are not hard and can reflect sound, usually through the use of affixing acoustic panels to the walls or ceilings in order to reduce reverberation to satisfactory levels. Some spaces such as cinemas may require both sound insulation and reverberation to be taken into account.
Certain levels may be required to comply with guidance documents.
The cost of poor room acoustics
Failing to design or understand room acoustics correctly does have a negative effect on those using the room or space.
Losing staff to sickness as a result of stress or anxiety impacts a business through loss of productivity and the expense of temporary staff.
Inability for those using the room to correctly understand the conversation.
Multiple conversations becoming mixed and the customer not being able to understand correctly.
Loss of revenue through the loss of repeat customers or not being able to ‘sell’ the space in the first instance.
The cost of undertaking remedial action in both financial and time constraints.
Additional cost for providing PPE, that could be avoided.
Understanding what a room or space is to be used for is critical in ensuring the room acoustics perform to maximize the full potential of the room for all those using it.
Sound Insulation and Noise Break In/Out
Noise break in/out occurs where inadequately designed partitions, doors, glazing or adjoining services are incorporated into room design.
Walls, floors and ceilings should be designed and constructed to suit the application of the room or space. Where guidance is available this should be followed and noise source levels considered within this calculation.
The weak spot for any wall will be an area of glazing or doors within the structure. The main area of weakness will be the seals between the door leaf and frame/floor, with final designs taken all these factors into account.
Ductwork between offices can also be an issue if left unattenuated as this will allow sound to travel between adjoining rooms.
Sound insulation can be improved through alterations to the existing structure, however this can be an expensive process and we always advise that this is considered at the planning and design stage to avoid unnecessary expense or downtime in the future.
Reverberation is the build up of sound energy as it reflects off hard spaces within a room or space. The level is calculated by measuring the sound levels once the source has been turned off, as it decays by 60dB. The levels are then shown in seconds.
Treatment for reverberation is simple and can be easily undertaken as remedial or refurbishment works although it is generally easier (and cheaper) if undertaken as part of the planning and design process. Reverberation is reduced by the use of porous acoustic panels (usually foam or mineral fibre based products) applied to the walls and ceiling. The reverberation levels and area of treatment can easily be calculated or simulated in the majority of cases, although complex-shaped or high-performance rooms can be more complicated.
Associated Standards and Guidance Documents
BS 4142:2014+A1:2019 Methods for rating and assessing industrial and commercial sound
BS 8233:2014 – Guidance on Sound Insulation and Noise Reduction for Buildings
Approved Documents: Part E: Resistance to the passage of sound; Part F: Ventilation and Part O: Overheating
Acoustics, Ventilation and Overheating: Residential Design Guide January 2020
ProPG: Planning & Noise – New Residential Development, May 2017
WHO Guidelines for Community Noise
Calculation of Road Traffic Noise (CRTN)
Calculation of Railways Noise (CRN)
National Planning Policy Framework (NPPF)
Noise Policy Statement for England (NPSE)
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