Peak velocity pressure, q_b, at height z is calculated according to the procedure given in NA.2.17.

Annex A of "NA to BS EN 1991-1-4:2005" shows flow diagrams for determination of q_b (i.e., Figures A.NA.1 and A.NA.2). These diagrams are implemented. Note that diagrams refer to Figures NA.3, NA.4, NA.5, NA.6, NA.7 and NA.8.

It is also possible to enter a constant value of q_b in the program. In this case, there is no need to calculate v_m exclusively.