Despite protests by Brentsville District residents that more industry in their neighborhood could lower property values and invade their privacy, the Prince William County Board of Supervisors agreed last week to rezone 30 acres that was zoned light industrial in 1979 to heavy industrial, allowing an Arlington woodworking company to locate on the property.

About 30 residents attended the public hearing held before the board voted. Several argued that a rezoning would destroy the buffer zone between their homes and farms and nearby industries. The supervisors also received a petition signed by approximately 150 persons who said they opposed the zoning change.

Brentsville Supervisor Joseph Reading said that while he sympathized with the residents, he "never looks at petitioners' names -- just the addresses. And some of those people live so far in the western end of the county that I doubt they even know where Wellington Road is. People will sign anything."

As for the residents, Reading said he "doesn't blame them" for opposing industrial development per se, but said he "would have more sympathy for them if they'd done their homework."

According to Reading, the board voted to approve the request because light industrial zoning meant in 1979 what heavy industrial means today. Changes in the zoning code approved by the board two years ago show that manufacturing plants were an allowed use of land zoned for light industry in the original ordinance, but that allowed uses of land zoned light industrial now include business offices, publishing and printing, data processing and similar businesses.

"It isn't the designation itself that's important here," Reading said. "It's what the land will be used for."

A spokesman for the applicant told the board that the Arlington woodworking plant would need only 10 acres of the property but that proffers will include keeping out certain "undesirable" businesses such as automobile graveyards, sanitary landfills, mining operations and automobile painting and repairing operations.

The building, which will have a brick front, will be set 85 feet from Wellington Road, with landscaping 35 feet from the road and an eight-foot chain link fence slatted with redwood in back of that. The 30 acres are part of a 105-acre tract owned by the Mary C. Flannery estate.

The board also directed the county attorney to take legal action against a man who has been running an automobile repair shop illegally for four years despite repeated requests by the county to cease operation. Vern Enger, owner of a shop at Centreville Road and Browns Lane in Brentsville that the county said is hidden by overgrown weeds, junked cars and a chain-link fence, has been trying to rezone the 2.2 acres from residential to commercial, although the operation would be considered heavy industrial, according to zoning administrator Sager Williams.

In other business the board unanimously approved requests from six of the county's volunteer fire departments to appropriate funds for various projects. They are:

* The Dumfries-Triangle Fire Department -- $30,000 for immediate construction costs and $4,000 in reserve for purchase of a pumper.

* Occoquan-Woodbridge-Lorton Fire Department -- $45,000 for building additions and $12,822 for equipment maintenance.

* Coles Fire Department -- $56,411 for the first payment on a new fire engine, station modifications and other items.