Update: The BB93 Update was officially released on December 19, 2014. Access it here.

Since its introduction in 2003, BB93 guidelines have set the standard for acoustic design and requirements in UK schools. However, it has been obvious for sometime that the guidelines have failed to stay up-to-date with the modernisation of schools and the continuing complexity of these spaces – leading to the announcement of a comprehensive review of the guidelines back in 2008.

Well, after more than five years, the updated BB93 has been released.

5 Take Outs From The BB93 Update:

  • There is a standard set for IT Suites in schools.
  • Schools can no longer hide behind Alternative Performance Standards (APS) (where spaces have a pre-existing acoustic compromise and do not need to uphold the same acoustic standard). The BB93 update does not allow APS to be applied with common issues such as serving hatches; and where an APS must be applied, they are only allowed to be 5 decibels less stringent than standards for new buildings.
  • Conditions for sports halls have been relaxed. Before the update, sports halls had to meet a reverberation time (the length of time it takes from a noise being produced to when it dies out) of 1.5 seconds. This condition has been relaxed to 2 seconds.
  • Measuring the effectiveness of a building envelope at protecting from exterior noise is now measured with the assumption that the weather is mild, as opposed to the previous assumption of being mid-summer. As Peter Symons, Director of Knauf AMF Ceilings told ‘Interiors Focus’ “that meant assuming every window was open – and that drastically cut the effectiveness of any sound insulation”. The new conditions allow only a few windows to be open during testing, relaxing the amount of external noise at the time of testing.
  • Special needs teaching spaces that need to meet acoustic standards have now been expanded to include spaces used for students with English as a second language and other broader learning disadvantages.

The new decibel and reverberation time guidelines for both refurbished and pre-existing schools are outlined as follows:


Updated BB93 Decibel Levels

Room New Build (dB  limit) Refurbishment (dB limit)
General teaching areas (classroom, seminar room, small group room) 35 40
Open plan teaching area / breakout area 40 45
Primary/secondary music room/ performance/recital room 35 40
Ensemble Room 30 35
Lecture Room 35 40
Special hearing and communication teaching spaces 30 35
Study Room 40 45
Libraries 40 45
Science Labs/Design and Tech rooms 40 45
Drama Studio/Assembly Hall/ Multi-use Hall 35 40
Atrium/Circulation Space 45 50
Sports hall/ Dance studio 40 45
Swimming Pool 50 55
Dining Room 45 50

Updated BB93 Reverberation Times

Room New Build (seconds) Refurbishment (seconds)
General teaching areas (classroom, seminar room, small group room) ≤ 0.8 ≤1.0
Open plan teaching area / breakout area  ≤ 0.5/≤1.2  ≤ 0.5/≤1.2
Primary/secondary music room/recital room  ≤1.0/≤1.0 /1.0 – 1.5   ≤1.0/≤1.0 /1.0 – 1.5
Ensemble Room  0.6 – 1.2  0.6 – 1.2
Lecture Room   ≤1.0  ≤1.0
Special hearing and communication teaching spaces  ≤ 0.4  ≤ 0.4
Multi-purpose hall  0.8- 1.2  0.8 – 1.5
Libraries  ≤1.0  ≤ 1.2
Science Labs/Design and Tech rooms  ≤ 0.8  ≤1.0
Drama Studio  ≤1.0  ≤1.0
Atrium/Circulation Space  ≤1.5  ≤ 2.0
Sports hall/ Dance studio  ≤1.5/≤1.2  ≤ 2.0/≤1.5
Swimming Pool  ≤ (1.5 – 2.0)  ≤ 2.0
Dining Room  ≤ 1.0  ≤ 1.5

Reading Between The Lines

A quick look at these broad changes shows minor tweaks to the BB93 update and a more realistic framework for schools to meet.

For any school, additional costs are always going to be a major concern. With the BB93 update, most can rest assured. Any additional costs for schools created by the update will mostly affect schools with contractors that cut corners. Acoustic consideration at the time of building design is still the most effective way to prevent your school incurring additional costs later down the line.


  • Whitehead, T. (2014). Volume Control. Interiors Focus, pp.20-23.
  • Hopkins, C. et al (2003). Building Bulletin 93. 1st ed.