The D.C. School Board last night voted to close six public elementary schools, a move that will affect only about 147 students.

Of the six schools, only one, Lennox Elementary, at 5th and G streets SE, is currently being used for daily classes.

Of the other five, Bruce Elementary, at 770 Kenyon St. NW, has been used for school system administrative offices. Magruder Elementary, also in Northwest at 16th and M streets, has been used for several years to house D.C. government-sponsored women's programs. The programs will be unaffected by the school closings.

Bruce, built in 1882, was characterized in a school administrative report as being in "poor" and "unsanitary" condition. It will be retained for school system offices by the school board at a cost of about $92,000 a year. Magruder will also be retained, as school officials hope to use it as leverage for bringing in developers for the restoration of the historic Sumner School next door.

Hayes Elementary, at 5th and K streets NE, which currently houses school administrative offices and a Department of Human Resources day care center, also will be closed. Though the school property will be returned to the city's Department of General Resources, the day care center will continue to operate at the school.

Congress Heights Elementary, at 6th Street and Alabama Avenue SE, which is now being used for a city-run pre-school program, will be returned to the city within one year.

Grimke Elementary, at Vermont Avenue and T Street NW, will be closed, but not until the school board can find other facilities to house special education programs for the 70 handicapped children who now attend classes there.

The school board, which met in a special session at Dunbar High School. also discussed closing Jefferson Junior High and Randall Senior High schools in Southwest, Hine Jr. High in Southeast and Garnett-Patterson Junior High in Northwest, but those proposals were voted down by large margins.