NJD...
Get a copy of Air Force Manual 32-1123(I)*** ~Airfield & Heliport Planning & Design.
See Attachment 7: it lists (2) locations to call for this [official] data.... and there is a boat-load of other good design info You NEED to know.
*** = Army TM 5-803-7
*** = Navy Facilities Engineering Command Pub P-971
NOTE: IHS, or equivalent spec/data services, have this document on-line.
Regards, Wil Taylor