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For generating out-of-plane loads on cladding and secondary structural members supporting the cladding, using the all-heights method, external pressure co-efficients Cp are given in NBC 4.1.7.5.(4) and shown in the diagram in Note A-4.1.7.5.(4). There are higher pressures on end zones that have one-tenth of the building width.
The external gust effect factor Cg from 4.1.7.3.(8) is 2.5 for components and cladding as opposed to 2.0 for the main wind force resisting system.
Using NBC 2010, the coefficients are specified in Figure I-15 as local pressure coefficients Cp* for both interior and end zones. According to Structural Commentary 29, these apply to areas about the size of a window, so they are applied to the design of sheathing and nail withdrawal.