The Ontario Building Code | Underground Walkway
220.127.116.11. Underground Walkway
(1) An underground walkway shall not be designed or used for any purpose other than pedestrian travel unless,
(a) the purpose is permitted, and
(b) sprinklers are installed in any space in the walkway containing an occupancy.
(2) buildingsconnected by an underground walkway shall be separated from the walkway by a fire separation with a fire-resistance rating not less than 1 h.
(3) An underground walkway shall be of noncombustible construction suitable for an underground location.
(4) In an underground walkway,
(a) smoke barrier doors shall be installed at intervals of not more than 100 m, or
(b) the travel distance from the door of an adjacent room or space to the nearest exitshall be not more than one and a half times the least allowable travel distance to an exit for any of the adjacent occupancies as permitted by Sentence 18.104.22.168.(1).
(5) An underground walkway between buildings shall be not more than 9 m wide.