Technical Booklet D Structure·Page 12
Span Definition
Defines span as the distance measured along the centre line of a member between the centres of any two adjacent bearings or supports, with a note clarifying that spans in Part 4B of Section 4 are clear spans measured between the faces of supports.
Span – the distance measured along the centre line of a member between the centres of any two adjacent bearings or supports.
Note: the spans given in Part 4B of Section 4 for floor joists, rafters, purlins, ceiling joists, binders and roof joists are clear spans, i.e. spans between the faces of the supports.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/Technical Booklet D - Structure.pdf