During analysis of external pipework,
Structural department indicated design windspeed of 115 mph.

I add this to the load cases:

+x
-x
+z
-z


But, do we normally add this wind force to the vertical directions? ie +/- Y?
Yor answers are appreciated.

If you're subject to a 115mph vertical wind, you're probably in the middle of a tornado and have bigger problems. :-)