Fairfax County this week approved a developer's plan to build 78 detached houses near a proposed new firing range at the Lorton prison facility in the southern part of the county.

The Board of Supervisors agreed to rezone 32 acres adjacent to the prison after considering and rejecting a proposal to require the builder to post a sign telling prospective buyers of the nearby prison.

The builder for his part indicated to the board that he will tell people if they ask but will not volunteer the information, since he expects that would "handicap" sales.

The property is located on the southeast corner of Hooes and Silverbrook roads.

The board agreed to change the zoning from one house per acre to three after debating the merits of new home construction near the prison facility.

"This borders the Lorton maximum-security section," supervisor T. Farrell Egge told the board.

However, 5,500 feet of pastureland separates that Lorton facility from the borders of the housing development, according to the Fairfax County planning staff.

Even though the staff report said people using a new firing range at the Lorton facility will be firing toward the building sites, the staff said that "stray bullets should not be a problem" because of the design of the firing range.

The range will be buried in the ground and have a special steel-plated roof running parallel to the range, according to the staff.

A "significant steel barrier" is also planned along the edge of the firing range, the staff said.

"Are you going to tell folks how close . . .the houses are to the driving range?" one supervisor asked a lawyer representing the developer, Carbone Enterprises Inc.

"People who come from out of town are not familiar with the problems we in Fairfax County have with Lorton," said Centreville supervisor Martha Pennino.

"If someone is moving from Boston or North Carolina they are not going to know about it," she said. "The first time I saw Lorton, I thought it was a college campus."

Supervisor Joe Alexander of the Lee district said the Board of Supervisors has the right to require that the builder post notices.

"It is only right that we let the people know," Alexander said.

Lawyers for the developers said, "We feel people know."

Alexander said the board has required developers of residential neighborhoods in areas near the yet-to-be-built Springfield Bypass to post signs telling those looking for new homes exactly where the road is going to be built to guarantee that buyers are aware that a major road is planned in the area.

A spokesman for Carbone Enterprises told the board Lorton has "been there since 1918."

Jerry Carbone, head of the company, told supervisors his company does not intend to tell people about the Lorton site directly. He said sales would be "handicapped" by saying the penal institution is there. However, he emphasized that he thinks there is a market for the houses. He said the homes are going to be built at the same market level of others now selling in the area.

Lawyers argued that other Lorton developers had not been required to post signs indicating the location of the penal facility in relation to either town houses or single-family detached homes. "We have known exactly where it is all along. There are three or four projects in a closer radius than ours to Lorton," Carbone said.

The Carbone development will be one of the few new detached developments in the area.

"What they will be buying is at a better price than in McLean," Carbone said.

"Everything that has been done there in the Lorton area is town houses. We could have put 120 town houses in there but we wanted to provide some detached housing at a reasonable price," he said.

Carbone said nearby town house projects with prices beginning in the $60,000 range are selling rapidly. He plans to market detached homes in the high $70,000 to the low $80,000 range.

"You cannot find a single-family detached house in Fairfax for less than $90,000," he said.

In an interview later he said, "The board wanted me to put up a big sign saying the prison is 1.5 miles away. If anybody asks, I will tell them. It is the obligation of any builder to answer any question asked."

He said he doubted purchasers would buy his houses without driving around and seeing the prison. He said the county was asking him to bear the burdens created by Lorton. "The obligation is for the county to do their job."