San Francisco will close borders to talented and artistic teens looking for a free and prestigious arts education at the city’s Ruth Asawa School of the Arts, a decision derided by many students, parents and teachers, yet unanimously approved by the school board Tuesday.

The decision ends the long-standing practice of allowing transfer students from other school districts to audition and gain admission to the high school, considered among the region’s most elite public art schools. The new policy will apply to admission for fall 2016. Current out-of-town students would be allowed to complete high school there, as well as those admitted for the incoming freshman class.

Opponents who crowded the school board chambers Tuesday night said the decision would water down the talent pool. Several students held signs that read, “SOTA = Talent,” and “Keep SOTA Pre-Professional,” using the common acronym for the school.

“I have friends that live three or four blocks away outside of San Francisco,” said Salena Nguyen, a junior theater student. “They don’t have any other options for an arts high school.”

Teachers also urged the board to allow them to maintain the quality of their programs.

“SOTA is a school for classical arts, not cartooning, graffiti art and hip-hop dance,” said teacher Donald Fontowitz in an e-mail to the school board and The Chronicle, urging the district to beef up classical art instruction in elementary and middle schools to increase city applicants. “We know how to run our school, we don't need help from downtown.”

Previous board policy restricted transfer students to 10 percent of the school’s enrollment. Currently, the 84 out-of-town students make up nearly 14 percent of enrollment across all art forms and nearly half of them are white. Several supportive speakers said many San Francisco students are talented, but don’t have classical training or need help with the audition process. Others lambasted the taxpayer money raised in San Francisco for the schools and then spent on the outsider students.

Board member Sandra Fewer urged the transfer students at the board meeting to fight for an arts school in their cities

“We serve San Francisco first,” she said. “This is their school. It is a San Francisco public school.

“You need to go to Contra Costa,” Fewer said. “I bet they have money for a school of the arts there.”

The resolution approved by the board also addressed a lack of diversity at the art school, which is predominantly white and Asian, with a lower percentage of English learners and low-income students than the district. The board called on the superintendent to provide art programs during the summer and create a task force to study and recommend ways to strengthen and expand art education to grow the applicant pool at School of the Arts.

Also on Tuesday, the school board voted to add Vietnamese and Arabic language programs in the district’s schools, including instruction in language and culture, by the 2017-18 school year.

Jill Tucker is a San Francisco Chronicle staff writer. E-mail: jtucker@sfchronicle.com Twitter: @jilltucker