(1)  Except as provided in Sentences (2) and (3), specified snow loads shall be not less than those calculated using the following formula:

S = C_b ∙ S_s + S_r

where,

   S =   specified snow load,

C_b =   basic snow load roof factor, which is 0.45 where the entire width of a roof does not exceed 4.3 m and 0.55 for all other roofs,

  S_s =   1-in-50 year ground snow load in kPa, determined according to MMAH Supplementary Standard SB-1, “Climatic and Seismic Data”, and

  S_r =   associated 1-in-50 year rain load in kPa, determined according to MMAH Supplementary Standard SB-1, “Climatic and Seismic Data”.

    (2)  In no case shall the specified snow load be less than 1 kPa.

    (3)  Bow string, arch or semi-circular roof trusses having an unsupported span greater than 6 m shall be designed in conformance with the snow load requirements in Subsection 4.1.6.

Article 9.4.2.2 Ontario Regulation 332/12 Building Code,   Information published by oncodes.ca for educational purposes only.