Chimney or Flue Pipe Walls (1) The walls of any chimney or flue pipe shall be constructed to be smoke- and flame-tight. Article 9.21.1.4 Ontario Regulation 332/12 Building Code, Information published by oncodes.ca for educational purposes only. Similar articles Footings Required Chimney Lining Materials Extension of Chimney Liners Clearance to the Fireplace Opening