Openings at 8 m and 10 m

Past about 8 m the governing load stops being the curtain and becomes the wind behind it. What changes in the specification, and what does not.

Wide-span shutters close the openings a warehouse, a workshop or a vehicle bay actually needs: 8.5 m by 8 m on the CD.80 section, 10.5 m by 10 m on CD.100.

Past roughly 8 m the governing load changes. On a domestic opening the curtain’s own weight is what the door has to handle; on a wide span it is wind pressure across the closed face, and that load arrives at the guides rather than at the barrel. Guide fixing centres, bracket design and the end caps on each slat all become specification items rather than standard details.

The slat thickens accordingly — 1.4 to 2.0 mm on CD.80, 1.5 to 2.5 mm on CD.100 — and the end caps are built in three layers, because a slat end on a door this size takes the wear first.

What does not change is the rule about the operator: it is still sized on the weighed curtain. A 10 m curtain is simply a heavy one, which past about 40 m² puts it into three-phase territory.