(1)
Except as provided in Sentences (2) and (3), the accumulation factor, Ca, for areas adjacent to roof-mounted vertical projections shall be calculated in accordance with Sentence 4.1.6.5.(1) using the following values for the peak accumulation factor, Ca0, and the drift length, xd:
(a)
Ca0 shall be taken as the lesser of,
(b)
xd shall be taken as the lesser of 3.35h and (2/3)l0, where h = height of the projection, and l0 = longest horizontal dimension of the projection. (See Note A-4.1.6.7.(1))
(2)
Ca is permitted to be calculated in accordance with Article 4.1.6.5. for larger projections. (See Note A-4.1.6.7.(2))
(3)
Where the longest horizontal dimension of the roof projection, l0, is less than 3 m, the drift surcharge adjacent to the projection need not be considered.