Priority School Building Programme

The Priority School Building Programme (PSBP)  takes a new approach to daylight design in schools, requiring all teaching, working and learning spaces to be analysed using Climate-based Daylight Modelling (CBDM).

Historically, traditional daylight design within the learning environment has been a numerical process focused on the adequacy of illumination under a static overcast sky – daylight factor (DF%). The ambition being to deliver a certain percentage of diffuse light into the space and to achieve a certain degree of uniformity.

In contrast, CBDM uses local weather files to analyse the annual illuminance profile, thereby providing far greater detailed information regarding the illuminance present within the space, throughout the year, under varying sky conditions. It therefore aims to more accurately predict likely interior illuminance levels, helps to reduce potential visual comfort issues (glare) and maximise potential energy savings from the electric lighting system, when used in conjunction with daylight-linked controls.

The analysis focuses on two dynamic daylight metrics; Spatial Daylight Autonomy (sDA) and useful Daylight Illuminance (UDI).
  • Spatial Daylight Autonomy - sDA(300/50%)
  • The Spatial Daylight Autonomy (sDA) should be 50% or greater, across at least 50% of the working plane, during occupied hours. The target illuminance (typ. 300lux) should be achieved for more than 50% of the time, throughout a typical year during occupied hours (8.30am to 4.00pm) across at least 50% of the working plane
  • Useful Daylight Illuminance - UDI-a (100~3000lux)
  • The UDI-a (100-3000lux) should be >80% (ave) across the working plane during occupied hours. The level of illuminance provided below 100 Lux (UDI-s) and above 3000 Lux (UDI-e) should occur for no more than 20% of the time (ave).


The £4.4 billion Priority School Building Programme (PSBP) is rebuilding and refurbishing school buildings in the worst condition across the country. There are two phases of the programme covering a total of 537 schools. Under the first phase, PSBP1, 260 schools are being rebuilt and/or refurbished: 214 through capital grant and 46 using private finance. The first school opened in April 2014 and the vast majority of others will be open by the end of 2017, two years earlier than originally announced.

The Education & Skills Funding Agency (ESFA) Priority School Building Programme (PSBP1) takes a new approach to the design and analysis of daylight within schools. The ESFA Daylight Design Guide Rev 2 2014 and Facilities Output Specification (FOS) states that 80% of the 'Teaching & Learning Spaces', within new build projects, must meet the minimum targets for both Spatial Daylight Autonomy (sDA) and Useful Daylight Illuminance (UDI) utilising CBDM simulation techniques.
  • Teaching & Learning Space
  • All spaces within the school where 'Teaching' or 'Learning' activities will take place. This includes classrooms, laboratories, seminar, main hall, sports hall, dining hall and library. It does not include group rooms, offices or staff work rooms.


Under the second phase, PSBP2, individual blocks at 277 schools will be rebuilt and refurbished using capital grant. By focussing on individual school buildings rather than just whole schools, we will maximise the impact of our investment, helping funding go further to help the schools in most need. The ESFA plans for all PSBP2 schools to open their new or refurbished buildings by the end of 2021.

The Education & Skills Funding Agency (ESFA) Priority School Building Programme 2 (PSBP2) Generic Design Brief (GDB) 2017 uses the same Climate-based Daylight Modelling (CBDM) metrics, Spatial Daylight Autonomy & Useful Daylight Illuminance, but instead of 80% of the 'Teaching & Learning Spaces' being required to meet the minimum targets, the ESFA GDB defines six space types (L1 - L6), each with their own set of requirements for daylight compliance. Primarily, space types L1 - L3 require analysis via CBDM, with compliance targets set for each type.
  • Type L1 - Basic teaching (excluding drama and admin ofices)
  • 80% of L1 spaces are required to achieve both the sDA(300/50%) and UDI-a (100~3000lux) targets.
  • Type L2 - Hall, Dining, PE & Libraries
  • 75% of L2 spaces are required to achieve the Useful Daylight Illuminance target.
    • Type L3 - Group rooms, study areas & staff rooms
    • 60% of L3 spaces are required to achieve the Useful Daylight Illuminance target.
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