Roscoe L. Bloss, 56, a physicist who worked for the National Bureau of Standards for 30 years before retiring in July 1980, died Sept. 1 at Shady Grove Adventist Hospital in Rockville after a heart attack. He lived in Rockville.

Mr. Bloss was head of NBS's vibration measurements section from 1967 to 1969. He was chief of the engineering mechanics section until 1977. Prior to his retirement, when he received the agency's Certificate of Recognition, he was a group leader in the product safety technology division.

His professional memberships included the American Physical Society and the Society for Experimental Stress Analysis. He was chairman of the subcommittee on calibration of testing machines of the American Society for Testing Materials and last year received its Award of Merit.

Mr. Bloss, who was born in Colorado, served in the Army in Europe during World War II. He graduated from the University of Colorado in 1950 with a degree in engineering physics.

Survivors include his wife, the former Corine Shearer Carwile, a son, Gregory, and a daughter, Adrienne, all of Rockville, and three sisters, Euna Erickson of Fruita, Colo., Freda Michaelsen of Collbran, Colo., and Joan Baer of Osmond, Neb.

The family suggests that expressions of sympathy be in the form of contributions to the Memorial Fund of Christ Congregational Church, Silver Spring, Md.