Length of Fasteners Gypsum Board

(1)  The length of fasteners for gypsum board shall conform to Table 9.29.5.5., except that lesser depths of penetration are permitted for assemblies required to have a fire-resistance rating provided it can be shown, on the basis of fire tests, that such depths are adequate for the required rating.

Article 9.29.5.5. Ontario Regulation 332/12 Building Code,   Information published by oncodes.ca for educational purposes only.

Application of drywall finish

Source : Canada Mortgage and Housing Corporation (CMHC)