Harrison Somerville Sr., 71, retired president and board chairman of the Thos. Somerville Co., died Wednesday at his home in Summer after an apparent heart attack.

Mr. Somerville began in 1925 with the family-owned plumbing supply firm founded in Washington in the early 1860s. He served as president from 1966 to 1968, and then as chairman of the board until his retirement in 1974.

He was born in Washington and earned a bachelor's degree from George Washington University.

Mr. Somerville was active in many civic and fraternal organizations. He belonged to the Washington rard of Trade, serving as chairman of the membership committee in the late in 1940s, and chairman of the aviation commivtee in the 1950s.

He was a past trustee of the Metropolitan Police Boys Club and past vice president of the Boys' Club of Washington.

Mr. Somerville was past president of the Middle-Atlantic Wholesalers Association, past president of the American Institute of Supply Association, and a founder of the Washington chapter of Sales and Marketing Executives.

He was a member of the Kiwanis Club of Washington, the Hexagon Club, the Mount Pleasant Lodge of the Masons and the Ancient Order of y his wife, Florence, of the home in Sumner; two daughters, F. Christina Stickle, of Bethesda, and Sandra Hoyt, of Sumner; a son, Harrison Jr., of Potomac; eight grandchildren, and a great-grandchild.

The family suggests that expressions of sympathy be in the form of contributions to the Kiwanis Club of Washington or to the American Heart Association.