Pressures on parapets for rigid or flexible structures are calculated as follows:

Pp= qp(GCpn)

(27.3-3)

where

Pp	=	combined net pressure on parapet
qp	=	velocity pressure evaluated at top of parapet
GCpn	=	$\{\begin{array}{cc}+1.5& \text{for windward parapet}\\ -1.0& \text{for leeward parapet}\end{array}$