Calvin Siddell Hannum, 63, a retired Army colonel who was decorated for gallantry in two wars, died at Fairfax Hospital Saturday following heart surgery.

Col. Hannum was born in Pittsfield, Mass., and educated at the University of Massachusetts. He entered the Army in 1941 and retired in 1969.At the time of his death, he was administrator of research contracts at George Washington University.

Col. Hannum served as an armored officer in the North African and European campaigns of World War II. He was twice decorated with the Silver Star Medal and also received the Purple Heart Medal. He won a third Silver Star in the Korean conflict. His otherdecorations included three Legions of Merit.

Apart from World War II and Korea, Col. Hannum had several assignments with U.S. and NATO forces in Europe and Turkey. He also was in the office of the Secretary of Defense from 1966 to 1969.

Survivors include his wife, Virginia, of Annandale, where the family established a home in the early 1950s: two sons, David and Robert, and one daughter. Marie, all of the home: and a brother, Latimer Hannum, of Paupack, Pa.

The family suggests that expressions of sympathy be in the form of contributions of the SHARE Home Coommittee of St. Micheal's Catholic Church, Annandale.