(1)
Where the installation of heating supply ducts in walls and floors creates a space between the duct and construction material, the space shall be firestopped with noncombustible material at each end.
(2)
Ducts shall be securely supported by metal hangers, straps, lugs or brackets, except that, where zero clearance is permitted, wooden brackets are permitted to be used.
(3)
All round duct joints shall be tight-fitting and lapped not less than 25 mm.
(4)
Rectangular duct connections shall be made with S and drive cleats or equivalent mechanical connections.
(4.1)
Rectangular panels in plenums and ducts more than 300 mm wide shall be shaped to provide sufficient stiffness.
(5)
Duct systems shall have no openings other than those required for the proper operation and maintenance of the system.