The Fairfax County Board of Supervisors this week approved commercial construction next to an elementary school near Tysons Corner after the developers agreed to provide safeguards for the schoolchildren.

Representatives of John G. Georgelas & Sons Inc. agreed to last-minute handwritten proffers, or promises, designed to guarantee the safety of children attending Freedom Hill Elementary School, off Old Courthouse Road, before the board approved construction of office buildings adjacent to the school.

Nancy Jones, president of the Freedom Hill PTA, told the board that parents basically did not oppose the change to commercial zoning on the four-acre site.

"There is deep concern" about the school, its borders and its playgrounds, she said. Jones said there is a fear of "a possible blatant lack of safety concerns."

She asked for "sufficient barriers between the work site and the school" and voiced concern about construction machinery and road changes that she said could endanger the schoolchildren.

Developers agreed to notify the PTA of their construction schedule and promised to build a brick wall between the development and the school once construction is finished. Meanwhile, the developer will provide temporary fencing.

"We will in turn monitor the children. We need to do all that is necessary for the safekeeping of these little people between the ages of 3 and 12," Jones said.

Freedom Hill school is almost surrounded on the north side by commercial development that now engulfs Old Courthouse Road, which is considered to be the southern boundary of Tysons Corner.

There has been considerable discussion among community leaders and school officials over the Freedom Hill school's future because of decreasing enrollments. However, during the past 18 months, several major single-family detached residential developments have been built south, east and west of Freedom Hill. Last year, the county put a new roof on the building in spite of rumors that it might be closed. The Fairfax County Board of Education is expected to review elementary school boundaries in the next few months.

A spokesman for the developer said the proposal represented "an assemblage of five parcels on the south side of Old Courthouse Road. These have been the subject of numerous rezonings."

Two low-rise office buildings are planned. Sidewalks will be built along Old Courthouse in front of the site. The developer also promised to make sure that all construction equipment is kept off school land.

The tract, which borders on Old Courthouse Road between Lord Fairfax Road and George Washington Road, also abuts the recently realigned Gallows Road. Developers said much of the traffic from the project would be concentrated in the afternoons after schoolchildren had gone.