Technical Booklet D Structure·Page 28·4B.9
Roof member sizes for imposed loads
Tables 4B.11 to 4B.44 specify roof member sizes for imposed loads of 0.75 kN/m² and 1.00 kN/m², with the applicable loading depending on site elevation and zone location as shown in Table 4B.2 and Diagram 4B.2.
Tables 4B.11 to 4B.44 give the sizes of certain roof members for imposed loads of 0.75 kN/m2 and 1.00 kN/m2. The loading applicable at a particular site depends on the elevation of that site above sea level and the zone in which it is situated. (See Table 4B.2 and Diagram 4B.2.)
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/regional/Technical Booklet D - Structure.pdf