The former American Canyon City Hall may become the new home for the library in Napa County’s second-biggest city.

Napa City-County Library officials say they may soon hire an architect to evaluate if the vacant city building could be renovated into a new library. If the answer is yes, revamping the structure and preparing it for the public could take three years.

“We’re just at the very beginning,” Napa City-County Library Director Danis Kreimeier said this week.

Napa County Public Works Director Don Ridenhour, whose department oversees capital projects, said architects have until Sept. 11 to apply for the evaluation work. Once hired, the consultant will assess the structural soundness of the 5,000-square-foot building to make sure it can be retrofitted and effectively redesigned. The consultant will also have to determine if the project is economically feasible, Kreimeier said.

 In July, Napa County supervisors set aside $55,000 for the study, saying American Canyon’s library — now crammed into a nearby office space at Canyon Plaza — needs more room.

American Canyon City Manager Rich Ramirez said the city has agreed not to sell, lease or rent the building for six months while the feasibility study is completed. The former City Hall building has been empty since January, when the city opened a new City Hall a mile to the north, at 4381 Broadway near Napa Junction Road.

Having the branch at the former City Hall would give the public more space and reduce the city’s overall operating costs, Ramirez said.

The city pays $79,000 a year on the lease of the 3,000 square-foot space in Canyon Plaza, a shopping and office plaza owned and managed by Rick Hess of R.H. Hess Development Co.

Terry Birkholz, the Napa City-County Library commissioner from American Canyon, is grateful for the support of the county supervisors and hoping for the best.

“It sounds promising,” she said.

Library representatives, including Birkholz, have said repeatedly that American Canyon’s library branch is too small for a city that continues to grow in population. American Canyon’s population increased by 1.8 percent in 2008, to 16,500 people, according to the state Department of Finance. That follows years of much more explosive growth.

According to library officials, the American Canyon branch’s circulation increased from 76,000 books and other materials in 2006-2007 to 99,000 in 2008-2009.

Birkholz said a bigger library will offer space to store books for Friends of the American Canyon Library public sales, proceeds of which benefit the American Canyon branch. The books were until recently kept at the city’s former police station on Elliott Drive. When the city decided to renovate that building and make it a senior center, the books were shipped to temporary quarters at the new City Hall.