BRE AP68 PDF

Protractor set (2nd series), numbers 1 to 10 plus a guide. The full set of protractors which covers rooflight and side windows, and both overcast and uniform skies. The protractors calculate the sky component of daylight factor. In conjunction with BRE Digests 309 and 310, they can be used to find the daylight factor at a point indoors. Price includes VAT.

Sometimes people ask if they can be used to assess the loss of light to an existing building following construction of a development next door. We don't recommend them for that purpose. Instead we advise using BR209 'Site layout planning for daylight and sunlight'.