Ramon Granados, 68, a former volunteer fire chief in Prince George's County and a retired employe of the U.S. Capitol Architect's Office, died of cardiac arrest Tuesday at St. Mary's Hospital in Leonardtown, Md. He was a resident of Hollywood, Md.

He joined the Riverdale Heights Volunteer Fire Department in 1929 and was its chief from 1940 to 1952. He moved to Bowie in the early 1960s and was a member of the Bowie Volunteer Fire Department for many years.

Mr. Granados was president of the Prince George's County Volunteer Firemen's Association in 1944 and 1945 and had belonged to the Maryland State Firemen's Association.

From 1935 to 1967, he was a truck driver for the Continental Baking Company and was a business agent for the Teamsters' Local 33 during much of this time. He then worked at the U.S. Capitol as an airconditioning mechanic before retiring in November 1979.

Mr. Granados was a native of Washington. He lived in Mount Rainier, Riverdale, and Bowie before moving to Hollywood in 1974.

Survivors include his wife, Katherine C., of Hollywood; two sons, Michael and Ramon, both of Bowie; three brothers, Luis, of California, Md., Juan, of Hyattsville, and Tony, of Levittown, Pa.; four sisters, Rose Hill of Sun City Center, Fla., Clara Koch of Riverdale, Mary Sepulveda of Richmond, and Lola Klumpp of Avenel, N.J., and five grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to St. John's Catholic Church in Hollywood, Md.