Construction of Firewalls (1) Where firewalls are used, the requirements in Part 3 shall apply. Article 9.10.11.3 Ontario Regulation 332/12 Building Code, Information published by oncodes.ca for educational purposes only. Similar articles Moisture Content (Lumber) Masonry Support Rating For Wall Sheathing When Applying CSA O325 Maximum Spans for Glue-Laminated Floor Beams – 20f-E Grade(1)