SInce Mike Witte has already addressed the question about the kPa value in the EPW stat
file in the BLDG-SIM bulletin board, I'll refrain from any further comment on your first
question.

As to your second question, are you saying that the EPW format contains a field for
liquid precipitation (which it does), but that it's always empty on "all the weather files"?
Please keep in mind that the EPWs are derived from source weather files. If the source
weather file is a TMY3 or TMY2/IWEC, there should be liquid precipitation PROVIDED that it
was being recorded by the weather station.

Last word of advice: any questions about EPW weather files should be posted on the
energyplus-support, not the equest-users, bulletin board.

Joe

Joe Huang
White Box Technologies, Inc.
346 Rheem Blvd., Suite 205A
Moraga CA 94556
yjhuang at whiteboxtechnologies.com
http://weather.whiteboxtechnologies.com for simulation-ready weather data
(o) (925)388-0265
(c) (510)928-2683
"building energy simulations at your fingertips"