The British Association of Teachers of the Deaf
Promoting Excellence in Deaf Education

BB93 - current situation

BATOD has approached by members unsure about the current situation regarding BB93 following the meeting of the BB93 review group.

The recommendations contained in BB93 section 6 apply only to those rooms dedicated to the specialist teaching of HI pupils and do not apply to general teaching rooms where HI children may be taught alongside their hearing peers. The main difference between the recommendations for HI rooms and general classrooms is that the reverberation time (RT) is 0.6 seconds for general classrooms (some classrooms, DT for example, are even longer) and 0.4 for HI rooms. One of the reasons this has been agreed is that HI rooms are invariably smaller and it is easier to meet this recommendation in a small room. Providing 0.4 RT in a large (ordinary) classroom is more difficult and therefore more expensive. It should be noted that the improvement in signal to noise ratio (the most important indicator of speech transmission and intelligibility) between 0.6 and 0.4 is 1.5dB - thus the BB93 review panel's decision (this year) not to amend BB93 to recommend 0.4 for general classrooms.

August 2009