Compulsory in all educational spaces, including mainstream and special schools, nurseries, colleges, and alternative provision, although compliance is not compulsory in tertiary and higher educational establishments.
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What is Building Bulletin 93?
Building Bulletin 93 (BB93) is the key guidance document for acoustic design in schools in England and Wales. Its full title is “Acoustic Design of Schools: Performance Standards”. It was first published in 2003 alongside the introduction of Part E4 of the Building Regulations, which brought acoustic performance in schools into statutory control.
The latest version, published by the Department for Education (DfE) in 2015 (with minor updates since), sets out the minimum acoustic standards that must be met in all new schools and significant refurbishments or extensions. Its purpose is to ensure that classrooms, halls, music rooms, and other learning spaces have good acoustic conditions that support clear communication, effective teaching, and pupil wellbeing.
Why is BB93 Important?
Noise and poor acoustics can severely affect teaching and learning. Studies show that excessive background noise or reverberation makes it harder for students to understand teachers, especially for young children, those with hearing loss, or pupils who do not have English as their first language.
By providing clear, measurable standards, BB93 helps designers, architects, and acoustic consultants create learning spaces that:
- Minimise intrusive noise from outside or adjacent rooms.
- Reduce reverberation to improve speech intelligibility.
- Control noise from building services such as ventilation systems.
When Does BB93 Apply?
BB93 applies to:
- All new schools and academies.
- Extensions to existing schools.
- Refurbishments or material changes of use where the acoustic environment is significantly affected.
It covers all educational spaces, including mainstream and special schools, nurseries, colleges, and alternative provision, although compliance is not compulsory in tertiary and higher educational establishments.
What Does BB93 Include?
BB93 sets out mandatory performance standards and design guidance for several aspects of acoustics in schools. Key areas include:
1. Indoor Ambient Noise Levels
Each type of room has a maximum permissible ambient noise level, measured in decibels LAeq,30min. For example:
- A standard classroom should not exceed 35 dB LAeq,30min when unoccupied.
- SEND (Special Educational Needs and Disability) classrooms require even lower levels, typically no higher than 30 dB LAeq,30min.
Sources of ambient noise include external traffic, playgrounds, and building services such as ventilation systems. Designers must specify construction elements like walls, roofs, and windows that provide sufficient sound insulation.
2. Airborne Sound Insulation
BB93 sets minimum airborne sound insulation levels between rooms and spaces, defined by DnT,w values. For instance:
- Classroom-to-classroom walls typically require at least 45 dB DnT,w.
- Music practice rooms or drama studios may require higher levels to prevent disturbance.
Doors, glazing, and duct penetrations must be detailed carefully to avoid flanking paths where sound can bypass the main barrier wall/floor.
3. Impact Sound Insulation
For floors and stairs, BB93 specifies limits on impact sound transmission, ensuring that footsteps or dropped objects do not disturb classrooms below.
4. Reverberation Time
Each space must have a suitable reverberation time (RT60) to ensure clear speech. For example:
- A typical classroom should have an RT60 of 0.6 seconds or less.
- Large halls, music rooms, and SEND spaces have different targets.
This may involve using acoustic ceilings, wall panels, or other absorbent finishes.
5. External Noise Break-in
The document provides guidance on protecting schools from external noise sources, like roads or railways, which can affect teaching spaces if not properly addressed. Schools near noisy sites often require higher-spec glazing, upgraded façades, or mechanical ventilation systems that allow windows to remain closed.
6. Building Services Noise
Noise from HVAC systems, fans, or ductwork must also meet strict limits. Designers must specify low-noise equipment and proper vibration isolation to keep background noise within BB93 levels.
How is Compliance Checked?
Compliance with BB93 is typically demonstrated through:
- Design stage calculations and specifications.
- On-site acoustic testing after construction (airborne and impact sound insulation tests, reverberation time measurements, and ambient noise level checks).
ENS are employed to guide the design, carry out modelling, and conduct final testing to ensure the school meets the requirements before handover.
Benefits of Good Acoustic Design
Schools built to BB93 standards offer:
- Better speech intelligibility and learning outcomes.
- Lower teacher vocal strain.
- Improved inclusion for pupils with hearing loss or additional needs.
- Greater privacy for spaces like music rooms or staff areas.
- Compliance with Building Regulations (Part E4).
BB93 and BREEAM
Good acoustic design for schools is also linked to BREEAM (the Building Research Establishment Environmental Assessment Method) credits under Hea 05 for acoustic performance. Meeting or exceeding BB93 requirements often contributes to achieving a higher BREEAM rating and securing up to three (3) credits under Hea 05.
In Summary
Building Bulletin 93 is a vital piece of guidance that ensures schools in the UK provide learning environments where speech can be clearly heard, distractions are minimised, and pupils’ and teachers’ health and wellbeing are protected. It bridges building design, education, and acoustic science — making it essential reading for architects, engineers, and anyone involved in the design and construction of schools. For assistance with BB93 compliance, call ENS.