Symbols and Notations used in Snow Loads Design Data

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Symbols and Notations used in Snow Loads Design Data

This is a list of symbology used in related snow loads design and engineering webpages.

C_e = exposure factor as determined from Table E-2
C_s = slope factor as determined from Fig. E-2
C_t = thermal factor as determined from Table E-3
h_b = height of balanced snow load determined by dividing p_s by γ , in ft (m)
h_c = clear height from top of balanced snow load to (1) closest point on adjacent upper roof, (2) top of parapet, or (3) top of a projection on the roof, in ft (m)
h_d = height of snow drift, in ft (m)
h_o = height of obstruction above the surface of the roof, in ft (m)
I = importance factor as determined from Table E-4
l_u = length of the roof upwind of the drift, in ft (m)
L = roof length parallel to the ridge line, in ft (m)
p_d = maximum intensity of drift surcharge load, in lb/ft²(kN/m²)
p f = snow load on flat roofs (“flat” = roof slope ≤ 5◦), in lb/ft² (kN/m²)
pg = ground snow load as determined from Fig. 7-1 and Table E-1; or a site-specific analysis, in lb/ft² (kN/m²)
p_s = sloped roof snow load, in lb/ft² (kN/m²)
s = separation distance between buildings, in ft (m)
S = roof slope run for a rise of one
θ = roof slope on the leeward side, in degrees
w = width of snow drift, in ft (m)
W = horizontal distance from eave to ridge, in ft (m)

γ = snow density, in lb/ft³ (kN/m³) as determined from Eq. E-3 but not less than the following minimum values for low slope roofs.

Where:

p_g is 20 lb/ft² (0.96 kN/m²) or less,
p_f = (I ) pg (Importance factor times pg)

Where:

p_g exceeds 20 lb/ft²2 (0.96 kN/m²),
p_f = 20(I ) (20 lb/ft² times Importance factor)