SRS Acoustics for Schools

Acoustics for Schools - The SRS Guide to BB93 and Building Acoustics for Education

THE SRS SCHOOLS PLEDGE: "FREE ACOUSTIC ADVICE, DESIGN AND SPECIFICATIONS FOR ALL UK SCHOOLS."

Introduction
BB93 Activity ratings
Reverberation Time
Airborne Sound Insulation
Impact Sound Insulation
Ambient Noise Levels
Glossary of terminology
Useful links
About SRS

Example Applications:
Drama Room / Assembly Hall
Music Rooms
General Classroom
Gym / Canteen



 

Introduction

The construction standards of schools have been raised significantly to improve the environment that our children are taught in. An area of particular interest, which is maybe not immediately obvious, is that teaching and learning are both acoustically demanding activities. Detailed research has demonstrated that poor acoustics adversely affect both teaching and learning. Building Bulletin 93 (BB93) has been implemented to address these issues, promoting good acoustic design and construction of new school facilities.

In particular, BB93 offers guidance in these core areas:
• Target ambient noise levels for teaching areas
• Acoustic separation between adjacent spaces
• Lower reverberation time to promote speech intelligibility

This guide is intended to be an introduction to the aims of BB93, illustrating how each target can be met and demonstrating example constructions and installations. Sound Reduction Systems are the UK’s leading independent innovator of high performance acoustic products, developed by our team of qualified, Institute of Acoustics accredited acousticians. Because the requirements of each school are different, SRS offer bespoke solutions across the board from the refurbishment of a single classroom to assisting with complete projects.

Free Acoustic Advice, Design and Specification for all UK Schools: Sound Reduction Systems offer their industry leading knowledge and experience free of charge to help guide you to the best solution for your school, whether it is for BB93 compliance or just to improve the acoustics within your teaching environment. For your free consultation, please call 01204 380 074, e-mail bb93@soundreduction.co.uk

 

BB93 Activity ratings

The core of BB93 is understanding how each space within the school is affected by acoustics, as summarised in the table below. Each area is addressed in the subsequent sections of the following brochure.

 

 

Reverberation Time

Why? Classrooms and teaching areas with lots of hard surfaces will inevitably have long reverberation times or echoes, this leads to a ‘blurring’ of sounds which particularly impedes speech intelligibility. Longer reverberation times also raise reverberant noise levels within a room; to compensate the natural reaction is to raise your voice level, exacerbating the problem. To avoid this vicious cycle, adding acoustic absorption to the walls and ceiling of the room will quickly reduce the reverberation time.

How? Sonata absorbent panels are designed to introduce effective sound absorption into a teaching area discretely and are produced in three versions. All utilise non-fibrous acoustic foam cores to eliminate fibre fallout and can be fitted during term time. Sonata products can be colour matched to any RAL colour or finished in a range of attractive fabric finishes adding visual impact.
 

Sonata Aurio absorbers are fitted flush to walls and ceilings and are designed to add good broadband absorption. Typically, Sonata Aurio absorbers are used in more confined areas, such as corridors and small classrooms. They can also used in larger areas in conjunction with other Sonata absorber products to achieve perfect broadband absorption.

Sonata Vario absorbers offer greatly enhanced absorption, particularly at low frequency, over directly bonded absorbers and are suspended from easy to install ceiling or wall brackets. Sonata Vario absorbers work very well in classrooms and general teaching areas.

Sonata Duo Absorbers are the ultimate solution to reverberation, a vertical suspended panel that absorbs sound and will also act as a baffle, helping to break up standing waves within a space. Used in areas with demanding reverberation requirements such as large classrooms and halls, Sonata Duo panels will achieve target reverberation times with fewer panels than other conventional systems.

Soundproofing in schools – Drama / Assembly Hall:

If you're looking for effective soundproofing in schools for drama or assembly halls, the problem you'll need to counter is reverberation. That's because drama and assembly halls in schools tend to have lots of hard surfaces that will inevitably have long reverberation times or echoes. This creates a ‘blurring’ of sounds that causes particular problems with speech intelligibility, making soundproofing in school drama and assembly halls so much more vital.

 

These longer reverberation times in drama and assembly halls also raise reverberant noise levels in schools. To compensate, people tend to shout or speak louder, which makes the problem worse and makes the need for soundproofing within schools more important. This is a vicious cycle, and the usual solution to this schools soundproofing issue is to add acoustic absorption to the walls and ceiling of the drama or assembly halls to cut down the reverberation time.

Schools drama classrooms or assembly halls use a double-height space, with plenty of glazing for a light and airy space. The problem of understanding speech across the room is a particularly bad schools soundproofing issue, especially during group sessions when children are split up into smaller groups.

A target reverberation time of less than one second should be the aim. But that can be tough in a light airy drama or assembly room with lots of hard surfaces. Sonata Duo absorbers suspended from the ceiling create great soundproofing in schools' drama or assembly rooms, as you can add a large surface area of highly absorbent panels without changing the feel of the space.

Sonata absorbent panels subtly introduce effective sound absorption into a teaching area. They come in three versions, all of which use non-fibrous acoustic foam cores to eliminate fibre fallout. They can be fitted during term time. Sonata products can even be colour-matched to any RAL colour or finished in a range of attractive fabric finishes for visual impact.

Sonata Aurio absorbers fit flush to walls and ceilings and add good broadband absorption. They're a good schools soundproofing option in corridors and small classrooms, but are equally effective in larger areas when used with other Sonata absorber products to achieve perfect broadband absorption.

Sonata Vario absorbers provide enhanced absorption, particularly at low frequency, over directly bonded absorbers and are suspended from easy to install ceiling or wall brackets. Sonata Vario absorbers work well in classrooms and general teaching areas as an option for soundproofing in schools.

For the ultimate solution to schools soundproofing issues in drama and assembly halls, how about Sonata Duo? They comprise a vertical suspended panel that absorbs sound and also acts as a baffle, helping to break up standing waves within a space. Used in areas with demanding reverberation requirements such as large classrooms and drama and assembly halls, Sonata Duo panels achieve target reverberation times with fewer panels than other conventional systems.

PRODUCTS:
 

Please see individual product datasheets for installation guidance, acoustic data and physical properties: Downloads

 

Airborne Sound Insulation

Why? Airborne sound is generated typically from sources such as voices and music and travels through the air into the structure of a building, and out again into adjoining rooms. Teaching and learning can be noisy activities, particularly in the case of music classrooms or areas where children are encouraged to work in groups and need to communicate. However, teaching and learning are also very sensitive to noise which can quickly distract children and increase teacher workload. Effective sound insulation allows teachers to maximise the potential of a space without disturbing neighbouring teaching areas.

How? The table on the preceding page rates the activity noise level of each room, and also its ‘noise tolerance’ level. This can then be used to suggest the standard of separation required, in terms of airborne noise, between two different activities/rooms using the following table:

 

Higher figures represent more stringent levels of separation, but it is important to highlight that these levels of performance are linked to meeting the appropriate level of reverberation in each room. High performance will be achieved using more sophisticated wall and floor structures, but this can be minimised by adjusting the layout of the school to minimise the instances of sensitive rooms being adjacent to spaces that generate higher noise levels.

Maxiboard is a very high performance building board that can be used to upgrade stud partitions and masonry walls to much higher specifications without taking up space or causing any more disruption than a standard dry lining system. Maxiboard is particularly robust and suited to the demanding school environment and can also be used to create high performance ceiling systems, such as the Maxi 60 Ceiling, to improve timber and concrete floor structures.

Where suspended ceiling systems are specified, SoundBlocker tiles can be use to achieve a range of different levels of performance levels.
 

Soundproofing in schools – Music Rooms:

Soundproofing in schools is vitally important and never more so than in music rooms. When soundproofing music rooms, which harbour all manner of noises from a range of musical instruments to voices, you're dealing with airborne noise. Airborne sound insulation is required to dampen down those voices and music that travel through the air into the structure of a building, and out again into adjoining rooms.

 

Why is soundproofing in schools so important? Teaching and learning involves plenty of two-way communication. Add to this the sound of violins, cellos or even drums and the disruption to other classes can be quite extreme. Effective sound insulation is vital, giving teachers the chance to maximise the potential of a space without disturbing other classrooms.

Check the table on the preceding page, which rates the activity noise level of each room and its ‘noise tolerance’ level. These can be used to suggest the standard of separation required, in terms of airborne noise, between two different activities/rooms using the following table:

 

 

Minimum DnT(Tmf,max),w(dB)		Activity Noise in Source Room
		Low	Average	High	Very High
Noise Tolerance in Receiver Room	High	30	35	45	55
	Medium	35	40	50	55
	Low	40	45	55	55
	Very Low	45	50	55	60

 

 

The higher the figure, the more stringent the level of separation for soundproofing in school music rooms. The levels of performance are linked to meeting the appropriate level of reverberation in each room. A high performance level of soundproofing can be achieved in schools with more sophisticated wall and floor structures in the music room. However, adjusting the layout of the school to keep noisy spaces away from quiet rooms can also help.
 

So what products work best for soundproofing in schools? At Sound Reduction Systems (SRS), we offer Maxiboard, which works very well in music rooms.Maxiboard  is a very high-performance building board that can be used to help soundproof music rooms in schools. It upgrades stud partitions and masonry walls to a high level and adds only around 17mm to the thickness of the music room walls. It's a robust soundproofing solution that's ideally suited to schools and takes up no more space than a standard dry lining system.

 

For soundproofing in schools, Maxiboard can create a high-performance partition between music practice rooms, so that the two rooms can be used at the same time. Sonata Vario absorbent panels can also control the reverberation time, which is achieved by calculating the reverberation time of the rooms, then adding absorption to the calculation until the time is brought to an acceptable level.

Sonata Vario absorbent panels are the natural choice for soundproofing school music rooms as they can be easily fixed out of reach on the ceiling, whilst quickly introducing effective absorption.

PRODUCTS:

 

 
 

Impact Noise Insulation

Why? Just as airborne noise can cause disruption, impact noise (the sound of foot fall or furniture being moved in rooms above) can also be a significant problem. This can be particularly apparent when rooms are used for dance or drama, or when lessons change and students move around.

How? The most effective way to reduce impact noise is to create a floating floor, a floor surface that is isolated from the structure below by introducing a resilient layer.

Depending on the structure of the floor and the floor finish specified there are different ways to achieve this, generic solutions that work with any floor finishes introduce inevitable compromises. Concrete floor screeds can be isolated using 5mm Impactafoam between the floor slab and the screed. Impactafoam can achieve impact noise improvements of up to 22 dB ΔLw. Timber and concrete floors can benefit further from Acoustilay, a high performance acoustic underlay, which can achieve an impact noise improvement 42 dB ΔLw, and in the case of timber floor structures Acoustilay can also offer additional airborne sound insulation too. Acoustilay can accept a wide range of floor finishes.

In addition to improving the floor surface using isolating materials, upgraded ceilings can further reduce impact noise. Maxiboard can be used to create high performance ceiling, and SoundBlocker can be used to upgrade suspended ceiling systems.


Soundproofing in schools – General Classrooms:

When considering soundproofing in schools, the issue of general classroom noise is an important one. Airborne noise causes disruption, as does impact noise from footfall or furniture being moved around in rooms above. These schools soundproofing issues are even more apparent when rooms are used for dance or drama, or when lessons change and students move around.
When you have one classroom directly below another in a school, you'll also get lots of impact noise through the floor, particularly from chairs scraping against the floor surface upstairs.

At Sound Reduction Systems (SRS), we have products that can help with soundproofing school classrooms. Acoustilay 3, which is bonded to the concrete slab and then overlaid with 9mm tongue and grooved MDF boarding, is one solution. The thin carpet can then be refitted without disturbing the isolation layer below it.

Acoustilay creates a simple and effective floating floor that greatly reduces impact noise during class changes. The floating floor surface is isolated from the structure below by introducing a resilient layer. Acoustilay can achieve an impact noise improvement of 42 dB ΔLw.

Other options for addressing these kinds of schools soundproofing impact noises in classrooms include isolating concrete floor screeds with 5mm Impactafoam between the floor slab and the screed. Impactafoam can achieve impact noise improvements of up to 22 dB ΔLw.

Another option for schools soundproofing in classrooms is introducing upgraded ceilings with Maxiboard, which can create high-performance ceilings, while SoundBlocker can upgrade suspended ceiling systems.

PRODUCTS:

   

Please see individual product datasheets for installation guidance, acoustic data and physical properties: Downloads

 

Ambient Noise Levels

Why? Noise is all around us, from adjacent classrooms to planes flying over head it is imperative that teaching areas have low an ambient noise levels so that children can easily follow instructions from teaching staff. Children can easily be distracted by external sources destroying their concentration levels which in turn disrupts teaching and places extra burdens on the staff. Typical recommended ambient noise levels for teaching spaces are around 35dB LAeq 30 mins, though more demanding spaces such as music practice rooms should achieve 30dB and less critical spaces such as kitchens can tolerate levels as high as 50dB.

How? Ambient or background noise sources will fall into two categories, external and internal noise sources. Internal noise sources in schools are varied, separation from other teaching areas is covered in here, but care should be taken to specify appropriate glazing and ventilation. External noise, such as from nearby roads or railway lines can be minimised early on in the project planning by identifying the noise sources and modifying the placing and layout of the school to minimise its exposure to noise. Rainfall is a significant source of external noise, particularly on profiled metal roofs over assembly halls, gymnasiums and class rooms. RainCheck can be used as an unobtrusive damping material adhered directly to the underside of the roof profile to achieve demonstrably significant reductions in rainfall noise, as measured to ISO 140-18, RainCheck is currently the only product tested to this standard. In addition, SoundBlocker panels can be used to upgrade suspended ceiling systems to further reduce noise passing into shared ceiling voids.
 

Soundproofing in schools: Gymnasium:

One of the main focuses of soundproofing in schools must be gyms. A large school gymnasium usually has a profiled metal roof. It's the centre of PE and sports lessons for children, usually around 30 at one time. It's a major soundproofing issue for schools because the gym is very reverberant. This is exaggerated when it rains, when pupils struggle to hear the teacher.
 

Other sources of noise that mean schools need soundproofing solutions in their gyms include adjacent classrooms and planes passing overhead. Teaching areas must have low ambient noise levels so that children can concentrate and easily follow instructions from teaching staff. Children can easily be distracted, which places extra burdens on the staff. Typical recommended ambient noise levels for teaching spaces are around 35dB LAeq 30 mins.

Ambient or background noise sources that require soundproofing in schools and gyms fall into external and internal noise sources. For internal noise sources, the right glazing and ventilation can help. For external noise, the noise sources should be identified at project-planning stage and the layout of the school adjusted.

At Sound Reduction Systems (SRS), we have a number of products that can help with these schools soundproofing issues in gyms. For example, we can place Sonata Duo Absorbent high up near the gym roof. We assess the anticipated reverberation levels of the gym and then calculate how much absorption is required to achieve the target RT.

Another way to soundproof school gyms is RainCheck. This is applied to the roof soffit to approximately a 60% coverage and will significantly reduce the noise from heavy rain so the space becomes usable in any weather. This is because rainfall is a significant source of external noise in schools, particularly on profiled metal roofs over assembly halls, gyms and classrooms. RainCheck is an effective schools soundproofing system that adheres directly to the underside of the roof profile to achieve demonstrably significant reductions in rainfall noise.

In addition, SoundBlocker panels can help with soundproofing issues in schools by upgrading suspended ceiling systems to further reduce noise passing into shared ceiling voids.

PRODUCTS:

  

Please see individual product datasheets for installation guidance, acoustic data and physical properties: Downloads

 

Glossary of terminology

Acoustic Absorption (not to be confused with insulation) – The quality of a material to absorb echoes, reducing reverberation but not used as ‘soundproofing’ to reduce noise
in adjacent spaces.

Acoustic Insulation (not to be confused with thermal insulation) – The quality of a material to reduce or stop noise passing from one side to another, typically through thick,
heavy constructions

Performance Criteria

Reverberation time (RT) – The reverberation time, in seconds, is quoted in terms of the mid-frequency reverberation time, Tmf, the arithmetic average of the reverberation times in the 500 Hz, 1 kHz and 2 kHz octave bands.

Airborne Sound Insulation DnT(Tmf, max),w (dB) – The standardised level difference with reference to the mid-frequency reverberation time in the receiving room

Impact sound insulation L’nT(Tmf, max),w (dB) – The standardized level measured in the receiver room with reference to the mid-frequency reverberation time of the receiver room.

Ambient noise levels - LAeq, 30min (dB) – An averaged ambient or background noise measurement over a period of 30 minutes and ‘A’ weighted to mirror the response of the human ear.

Useful Links

www.ioa.org.uk
www.association-of-noise-consultants.co.uk

About SRS

Sound Reduction Systems have 25 years of experience developing and producing high performance materials to address a wide range of acoustic challenges. We maintain excellent dialogues with the leading acoustic consultancies and architects to offer the best solutions available. In every instance, we would be delighted to work with you to help clarify the potentially mystifying field of acoustics, to understand the requirements presented and then assistance to selecting the most appropriate specification. All our products are backed up by ISO standard independent testing, details of which are available on request.

As well as schools and education, Sound Reduction Systems have experience with residential buildings, meeting Part E of the Building Regulation, hospitals and healthcare, offices and industrial acoustics and commercial applications.

Disclaimer:

Site conditions and installation standards vary. SRS cannot take responsibility for the performance of any installed system of which SRS products are only a part, or that have been installed incorrectly. Prior to installation, it is necessary to identify and eliminate possible flanking paths that may compromise the acoustic performance of any SRS product.