BB 101 Overheating Assessment: Ventilation, thermal comfort and indoor air quality in Schools

BB101 Overheating Assessment provides guidance for ventilation, thermal comfort and indoor air quality in schools; with the guidelines recently updated to align with the most recent industry best practice and health & safety standards. Its focus is on the health and wellbeing of students and teachers to promote learning.

The latest BB101 document accommodates the recommendations and methodology contained within CIBSE TM52. This approach has already been used through the Priority Schools Building Programme and the Department For Education (DfE) Facilities Output Specification (FOS).

To pass BB101 Overheating Assessment summer overheating criteria, the schools operative temperature using a DSY1 2020 weather file during the occupied period 9am – 4pm Monday to Friday between 1 May and 30 September. These are the criteria that BB101 is assessed:

Criterion 1: Hours of Exceedance (this is mandatory).
Criterion 2: Daily Weighted Exceedance (this is advisory).
Criterion 3: Upper Limit Temperature (this is advisory).
These criteria can be summed up:

1 – The first criterion sets a limit for the number of hours that the operative temperature can exceed the threshold comfort temperature (upper limit of the range of comfort temperature) by 1K or more during occupied hours of a typical non- heating season (1 May- 30 September). For schools this shall not be more than 40 hours.

2 – The second criteria deals with the severity of overheating within any one day, which can be as important as its frequency, the level of which is a function of both temperature rise and its duration. This criterion sets a daily limit for acceptability.

3 – The third criterion sets an absolute maximum daily temperature for a room, beyond which the level of overheating is unacceptable.

Walker Energy Analysis has a wealth of experience carrying out BB101 Overheating Assessment calculations for schools of all types, and with an extensive knowledge of the legislation and best methods of compliance.