INSTALLATION - PLANNING
24
TERRAIN CATEGORY
The terrain over which the approaching wind flows towards a structure must be assessed on the basis of the
following category descriptions:
Terrain Category 2: Open terrain, including grassland, with well-scattered obstructions having heights
generally from 1.5 m to 5 m, with no more than two obstructions per hectare, e.g. farmland and cleared
subdivisions with isolated trees and uncut grass.
Terrain Category 3: Terrain with numerous closely spaced obstructions having heights generally from 3 m to
10 m. The minimum density of obstructions shall be at least the equivalent of 10 house-size obstructions per
hectare, e.g. suburban housing or light industrial estates.
ROOF TYPE
Determine the roof type of the building where the PV modules are to be installed and select the appropriate
rail support.
Rail support systems are available as follows:
Roof Type
Roof Pitch
Rail Support Category
Rail Support Name (Options)
Standard tile
10 - 30º
Tile roof interface
Tile interface (Portrait)
Tile interface (Landscape)
Low profile tile
Flat tile interface
Slate
Slate interface
Metal
10 - 30º
Metal roof interface
Metal roof interface
Metal
Corrugated
< 10 º
or
< Latitude minus 15º
Tilt leg interface
10 - 15° adjustable tilt legs
15 - 30° adjustable tilt legs
30° fixed tilt legs
30 - 60° adjustable tilt legs
ROOF AREA
Determine the installation area on the roof (roof position area). The diagrams below show roof position areas
designated as “Edge Zone” areas and “Centre Zone” areas according to interface type.
Edge zone areas are subject to higher wind loadings and therefore will require closer rail support spacing.
Warning:
If any part of the system array is located in one of the edge zones, the entire array must use
the support spacing specified for the edge zones.
