Last reviewed: 2026-07-12 · Checked against the standards it cites · Editorial policy
Building Bulletin 93 (BB93) is the acoustic standard for schools in England. It sets maximum reverberation times and indoor ambient-noise limits by room type, and is the reference for meeting the Building Regulations' acoustic requirement (Approved Document E) in school buildings — for both new build and refurbishment.
- BB93 is the school acoustics standard for England. Approved Document E points to it as the way to demonstrate compliance for school buildings, in both new build and refurbishment.
- BB93 turns on two numbers. It sets a maximum mid-frequency reverberation time by room type — around 0.6 seconds for ordinary new-build teaching spaces — and caps indoor ambient noise.
- Panels alone do not make a school compliant. They control reverberation, one half of BB93; the other is limiting background noise, so a compliant design must address both.
- Claim performance only from measured data. The absorption you can rely on comes from the panel's tested αw or NRC at the mounting used, not a generic figure.
What BB93 is, and when it applies
Building Bulletin 93 — 'Acoustic design of schools: performance standards' — is the document that turns the Building Regulations' general acoustic requirement into concrete numbers for schools in England. Approved Document E points to BB93 as the way to demonstrate compliance for school buildings.
It applies to new schools and, in a proportionate way, to alterations and refurbishments. It covers mainstream and special schools, and sets tighter figures for rooms used by pupils with hearing impairment or special educational needs.
The two numbers BB93 turns on
Reverberation time. BB93 sets a maximum mid-frequency reverberation time for each room type — for example, ordinary teaching spaces in new-build sit around 0.6 seconds, with tighter figures for spaces used by hearing-impaired pupils and more relaxed ones for circulation. Controlling reverberation is what acoustic absorption is for.
Indoor ambient noise level. BB93 also caps the background noise (from ventilation, traffic and adjacent spaces) reaching a room, because intelligibility depends on the gap between the teacher's voice and the noise floor. Absorption helps reverberation and, indirectly, clarity — but it does not by itself fix a noise-ingress problem.
How do acoustic panels help a school meet BB93?
Reverberation is governed by how much sound absorption a room contains relative to its volume — the relationship in Sabine's equation. Hard classrooms with painted plaster, glass and hard floors have very little absorption, so speech smears and the room feels loud; adding absorptive panels or ceilings brings the reverberation time down toward the BB93 target.
The performance you can claim comes from the panel's measured αw or NRC at the mounting used, not from a generic figure. For a room used by pupils with hearing impairment, or where a fire-rated finish is also required, the specification tightens — which is where a fire-rated acoustic series and a qualified acoustician come in.
Getting it right on a real project
BB93 is a performance standard, not a shopping list: it tells you the target, not the product. The reliable route is to have an acoustician model each room, specify the absorption area and location needed to meet the reverberation and noise limits, and then select panels whose tested data delivers it.
Use the reverberation calculator to sanity-check whether a space is likely to need treatment and roughly how much — then confirm against measured data and the room-by-room BB93 targets before you specify.
Frequently asked questions
Is BB93 a legal requirement?
The Building Regulations require adequate protection against noise in school buildings, and Approved Document E identifies BB93 as the standard by which that is judged for schools in England. In practice, meeting BB93 is how a school building demonstrates it complies.
What reverberation time does BB93 ask for in a classroom?
For an ordinary new-build teaching space the mid-frequency reverberation target is around 0.6 seconds, with tighter figures for rooms used by hearing-impaired pupils. Always work to the specific figure for the room type in the current version of BB93.
Do acoustic panels alone make a school BB93-compliant?
Not on their own. Panels control reverberation, which is one half of BB93; the other is limiting background noise from ventilation, traffic and adjacent rooms. A compliant design addresses both, usually with an acoustician modelling each space.
Does BB93 apply to refurbishments?
Yes, proportionately. New buildings are expected to meet the full standards; alterations and refurbishments are expected to meet them as far as is reasonably practicable for the work being done. An acoustician can advise what applies to a given project.
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Specifying acoustic panels?
Order finishes to see and hear, model the room with the reverberation calculator, or send us the spaces and targets for panel selection and a quote. We publish no performance figure we cannot evidence — what that means for your project.