Arlington has taken the first step toward expanding its central library.

Last Saturday the Arlington County Board voted to begin negotiations to acquire a parcel of land just south of the present library site in Quincy Park in the Virginia Square area.

The land is intended for a 30,000-square-foot building and more parking. The current library building, which is 60,000 square feet, will be renovated.

"There will be more stack space, more seating area, a separate young adult room and a popular library with best sellers," said Charles M. Brown, Arlington's director of libraries.

The expansion site being eyed by the county is presently the site of the Arlington Funeral Home. It is bounded by N. Quincy Street, Fairfax Drive, N. Pollard Street and N. 10th Street.

It will be the first expansion of the central library in 20 years. Financing for the project comes from a $10.8 million bond approved by county voters in November 1986.

The present building was constructed in 1961 and was renovated in 1967. "It is literally crammed to the rafters," said Brown.

Improvements to the current building's electrical system are being planned. The system presently cannot supply the computers that are now an integral part of libraries, Brown said.

If negotiations for the added site are successful, construction bids will be solicited next fall and the new building and renovations will be complete by 1991, said Brown.

The final design of the new building project must be approved by the county board. County officials have promised that the library expansion will not reduce open space or recreational facilities at Quincy Park.

It is unclear whether the central library building will have to be closed while renovations are in progress.