The "c_pe" coefficients are calculated from Table 7.1 for windward and leeward surfaces. Note that windward and leeward surfaces are marked with the latter "D" and "E" in the figure, respectively.

Zone	D	E
h/d	Cpe = Cpe,10	Cpe = Cpe,10
5	+0.8	-0.7
1	+0.8	-0.5
≤ 0.25	+0.7	-0.3

Table 7.1 Recommended values of external pressure coefficients for vertical walls and rectangular buildings (only partial data for the table shown below)

The following points are important to note:

1. Pressure coefficient "c_pe" is divided into two components: overall coefficient "c_pe,10" (pressures on surfaces > 10 m²) and local coefficient "c_pe,1" (pressures < 1 m²). Current implementation does not count local effects, hence, it is assumed that "c_pe = c_pe,10". Also note that the equation given for Figure 7.2 is not implemented (i.e., interpolation of c_pe between c_pe,10 and c_pe,1).
2. In calculation of c_pe according to Table 7.1, the following rule is applied to obtain the value of d: if the extends of the story/stories above are greater than the extends of the current story, the greater extends from the stories above is used.
3. In calculation of c_pe according to Table 7.1, an option to apply a correction for lack of windward and leeward correlation is also included (see Section 7.2.2, Note (3)). In this case, the same rule applied to c_pe is followed to obtain "d".
4. The c_pe coefficients can be also directly entered by the user. In this case, values for X and Y directions are entered separately for windward and leeward surfaces.
5. Interpolation is applied for intermediate values of h/d in Table 7.1.