Terminating a sheet above and below a penetration creates an end span situation and sheet support and fastener patterns should be checked accordingly, or additional support must be provided. (See 220.127.116.11 Continuity.)
Penetrations requiring removal of a roof section greater than 300 mm x 300 mm require additional supporting framework. Ideally this should be in position before the roof cladding is fixed; alternatively, the supporting framework should be in position before cutting a hole in the cladding.
The additional support for larger penetrations must have the same strength as the adjacent purlins. Purlins and the support structure must be designed to take the additional weight of any plant exceeding 100 kg. Structural members must not be removed without engineering calculations.
The person who cuts a hole greater than 600 mm x 600 mm in the roof is responsible for safety precautions, preventing workers from falling through the gap. A hole of this size is regarded as a hazard under the Health and Safety in Employment Act.