DEMO — fictional range. Local brief only, NOT SENT. No personal data is collected or transmitted.
ARRAY
The roof decides the layout before the module does.
An array is laid out on a roof, and the roof has zones, obstructions and a structure. Starting from the module count produces a layout that has to be redrawn.
The four questions worth asking.
They are asked before the layout, because each one changes the array rather than the components.
- Which roof zone
- Edge and corner zones see higher wind, so they carry closer fixing centres
- What is in the way
- Vents, rooflights and plant decide the usable rectangle before the module does
- How the roof is built
- The structure decides where fixings can go, and therefore the rail direction
- Who maintains it
- Access and walkways are a layout decision, not an afterthought
Where each decision comes from
| Condition | What it decides | What it costs to get wrong |
|---|---|---|
| Exposed edge zone | Fixing centres and clamp count | Modules lifting in the first gale |
| Heavy snow region | Rail span and module tilt | A rail that deflects and cracks glass |
| Membrane roof | Whether a penetration is allowed at all | A warranty voided by the fixings |
| Tall building | Wind pressure adjusted for height | A design that was adequate at ground level |
The expensive mistake.
Designing from the module count. The array is drawn to fit the modules and then has to be forced onto a roof that has zones and obstructions, and the rework is in the fixings rather than in the drawing.
And the one that looks harmless.
Ignoring the edge zone. The middle of a roof and its corners do not see the same wind, and the corners are where arrays lift.