Louis E. (Ed) Purnell, 71, a retired insurance agent who had been active in Northern Virginia Community affairs, died Friday at Arlington Hospital after a heart attack. He had lived in Arlington since 1935.

Mr. Purnell was a special agent with the Lincoln National Life Insurance Co. from 1952 until retiring in 1974. He had worked for the Riggs National Bank from 1929 until joining the Lincoln Company.

A native of Baltimore, he moved to Washington as a boy, and graduated from Eastern High School in 1928. Later, he completed training at the American Institute of Banking.

Mr. Purnell was elected to the advisory board of the Arlington Agency on Aging in 1977. He was treasurer of the advisory board of Madison Center Associates, Inc., an adult day-care organization.

At the time of his death, he was president of the Arlington chapter of the American Association of Retired Persons. He had been on the board of directors since 1977.

Mr. Purnell had served as treasurer of Westmoreland Congregational Church here from 1937 to 1950. He became a deacon and then an elder of Trinity Presbyterian Church in Arlington in 1954. He had been active in many church organizations and had been chairman of the board of trustees. He was elected to the board of directors of Westminister Presbyterian Homes Inc. of the synod of Virginia.

He had served as a Boy Scout leader in Arlington for 12 years. A master Mason, he belonged to Columbia Lodge No. 285 in Arlington.

Mr. Purnell belonged to the Georgetown Lions Club and had been deputy district director of Zone 22C. At one time he had participated in a gerontology study at Johns Hopkins Medical Center.

He is survived by his wife of 48 years, the former Mary Augusta Kaiser of Arlington; two sons, Navy Cmdr. Louis S., of Owings, Md., and Brian H., of Pendleton, Ore.; a brother, Richard A., of Annapolis, and four grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the Trinity Presbyterian Church building fund.