COP v3.0:penetrations; penetrations-minimum-pitch

9.1 Penetrations Minimum Pitch 

Penetrations may be executed in roofs of any pitch down to the limit of 8° for corrugate and 3° for other profiles. Penetrations are allowed in the portion of curved roofs where the pitch falls below these limits, providing the penetration flashing bridges the apex and terminates where the pitch is a minimum of 3°.