INTRODUCTION
The SunLock General Engineering certificate helps installers to know how many roofs screws are required to securely hold the solar PV frame to the roof frame. This depends (in part) on the wind speed, which is higher in the edge zones of the roof. The image below shows how low pressure zones develop on the leading edge of each roof. As the wind could come from any direction, the standard defines edge zones on all edges of the roof.
The wind region map below also shows the structures should meet the standard required for installation for the region where it is installed according to AS/NZ1170.2:2021 standards.
GUIDE TO USE
Measure the overall breath ‘B’, depth ‘D’, and height ‘H’ of the house.
For example, ‘D’ is 10 metres, ‘B’ is 13 metres, and ‘H’ is 4 metres. The edge zones comprise the intermediate zone and the edge zone, which are in total ‘A’ wide. ‘A’ is the minimum value of either:
0.2 * B,
0.2 * D, or
H
In this case, ‘A’ is 0.2 x 8 = 2 metres wide. In most cases, the internal zone on the roof will be very small, and it is almost impossible to install a solar PV system within it. The image below shows the internal zones in yellow.
The edge zone and the intermediate zone are each ‘A/2’ wide. As a rough guide, use the fixing spacings for the “intermediate zone” shown in the table in the installation manual to work out how many you need. Then, add extra fixings if the row extends right into the edge zone.
For Further information
For further information contact SunLock on 1300 655 554 or order@sunlock.com.au.