The NZ Metal Roof and Wall Cladding Code of Practice is a comprehensive design & installation guide, and a recognised related document for Acceptable Solution E2/AS1 of the NZ Building Code.
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 3.5.8 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.