Warren Carl Hansen, 55, president of the Air Flow Co., a Gaithersburg firm that designs special purpose refrigeration equipment, died Dec. 30 at the Shady Grove Adventist Hospital in Rockville, after a heart attack.

Mr. Hansen, who was born in Chester, Pa., attended Harvard University and Pennsylvania University during the 1940s. He saw submarine duty in the South Pacific during World War II.

In 1948, he began his career in salesand manufacturing of industrial refrigeration equipment, as an overseas salesman for the Frick Co., of Waynesboro, Pa. He moved to Silver Spring in the early 1950s and became vice-president of H.W. Hottel, Inc. He also was the East Coast representative for Ellis and Watts Production.

In 1959, he founded the Air Flow Co. in Rockville. The company, which sells air-conditioning refrigeration and humidity equipment for companies in this country and overseas, now is located at the Montgomery Airpark in Gaithersburg. In 1976, Mr. Hansen received the President's "E" award for the organization's export division.

Mr. Hansen was president of the American Society of Heating, Refrigeration and Air Conditioning Engineers, chairman of the board of directors for the Montgomery County General Hospital, and a founding member of St. John's Lutheran Church in Rockville.

Survivors include his wife, E. Frances, of Gaithersburg; a son, Thomas K., of Mount Airy, Md.; two daughters, Laura M., of Gaithersburg, and Jean E., of Boulder, Colo.; two brothers, Earl, of Norfolk, Va., and Victor, of Harrisburg, Pa., and his stepfather, Victor Jensen of Philadelphia.