The Ontario Building Code | Lining or Backing
188.8.131.52. Lining or Backing
(1) Every steam or hot water radiator and convector located in a recess or concealed space or attached to the face of a wall of combustible constructionshall be provided with a noncombustible lining or backing.
(2) Every steam or hot water radiator and convector shall be installed to conform to the clearance requirements of Table 184.108.40.206.
6.2.9. Piping for Heating and Cooling Systems