rain on snow surcharge

huangyhg

rain on snow surcharge
in asce 7-05, is the rain on snow surcharge applied to the pf, or the minimum pf?
for a 20 psf ground snow, i=1, the pf = 14, however the minimum would be 20, depending on the roof type.  when applying the surcharge, is it added to 14, or the 20?  
it is added to the pf (14+5=20), not the minimum pf (20). but in this case the 20 would still control.