ºÃÉ«ÏÈÉúTV

Read our policy.

Changes at a glance
Key differences between the existing BB87 and the new requirements in BB93 compiled by Adrian James of Adrian James Acoustics
BB87, 1997BB93, 2002
Internal ambient noise levels Previously called background noise levels, which includes noise from teaching activities in adjacent spaces in addition to the indoor ambient noise from internal and external noise sources identified in BB93The indoor ambient noise levels in Table 1.1 of BB93 do not include noise from teaching activities in neighbouring rooms, which is addressed through specification of sound insulation. They include all other noise from internal and external noise sources except noise associated with classroom activities
Maximum indoor levelsGuidance was given that noise from aircraft and trains should not exceed 55 dB LA1 in teaching classroomsIt is now a requirement that noise from individual noisy events in certain rooms including classrooms should not regularly exceed 55 dB LA1,30mins
Sound insulation between roomsRequirements for weighted level of difference Dw are given in terms of a matrix as a function of noise tolerance and activity noise levelsThe sound insulation requirements are in some cases more onerous than in BB87. Use of doors communicating directly between classrooms is generally impracticable because these reduce sound insulation, Dw replaced by similar DnT (Tmf,max)
Sound insulation between rooms and corridorsDw quoted between rooms and corridors, but was not reproducibly measurable in practice because of the irregular dimensions of the corridors Requirements are given in Rw (weighted sound reduction index) for walls and doors, and there is a separate requirement for ventilators. Compliance has to be by calculation rather than measurement
Impact sound insulationNo requirementsNew requirements for impact sound insulation of floors over sensitive rooms (see page 8)
Reverberation times of roomsDefinition of Tmf was mean of 500 and 1000 Hz valuesDefinition of Tmf changed to mean of 500, 1000 and 2000 Hz values, which means there are limited permissible increases at lower frequencies. Some changes to room descriptions and values
Absorption in corridors, entrance halls and stairwellsNo requirementRequirements in terms of areas of sound absorbent material, as defined in Section 7 of the new Approved Document E
Open-plan spacesNo requirementUse of open-plan spaces for simultaneous teaching of several classes is strongly discouraged. If there is a real demonstrable need for such spaces, detailed acoustic modelling is needed to demonstrate that a Speech Transmission Index (STI) of 0.6 or above will be achieved
Design checksSchool designers were left to self certify compliance with the standardsSchool designers will have to submit information to satisfy building control bodies that the designs conform to the above requirements. Alternative criteria may be considered by ºÃÉ«ÏÈÉúTV Control bodies but must be fully and formally justified
CommissioningNo requirementIt is recommended that the client should include a requirement for acoustic testing in the building contract. The ºÃÉ«ÏÈÉúTV Control body may also request such a test
Footsteps on the classroom floor:
Maximum floor-impact sound levels Ìý
Type of room Maximum weighted BB93 standardised impact sound pressure level L'nT (Tmf,max),w dB
Nursery school playrooms65
Nursery school quiet rooms60
Primary school: classrooms, class bases, general teaching areas, small group rooms60
Secondary school: classrooms, general, teaching areas, seminar rooms, tutorial rooms, language laboratories60
Open-plan spacesÌý
Teaching areas60
Resource areas60
Music roomsÌý
Music classroom55
Small practice/group room55
Ensemble room55
Performance/recital room55
Recording studio55
Control room for recording55
Lecture roomsÌý
Small (fewer than 50 people)60
Large (more than 50 people)55
Other rooms Ìý
Classrooms designed specifically for use by hearing impaired pupils55
Study room (individual study, withdrawal, remedial work, teacher preparation)60
Libraries60
Science laboratories65
Drama studios55
Metalwork/woodwork classrooms, resource/light craft and practical work65
Assembly halls, multi-purpose halls (drama, PE, audio/visual presentations, assembly, occasional music)60
Audio-visual, video conference rooms60
Atria, circulation spaces used by pupils65
Indoor sports hall65
Gymnasium65
Dance studio60
Swimming pool65
Interviewing/counselling rooms, medical rooms60
Dining rooms65
Ancillary spacesÌý
Kitchens*65
Offices*, staff rooms*65
Corridors*, stairwells*65
Coats and changing areas*65
Toilets*65
* This applies only to teaching and learning spaces and is not intended to cover administration and ancillary spaces. For these areas the values are for guidance only.