Philadelphia ? Complaining of low pay, cold rooms and air laden with paint fumes and charcoal dust, models who pose nude at a Philadelphia art school voted Wednesday to join a union.

“We were at a loss about how to get the schools to pay attention to us,” said Claire Hankins, 39, who led the effort to organize artists’ models at the Moore College of Art and Design.

The union vote came after the National Labor Relations Board rejected the school’s argument that the models were independent contractors.

“We feel they are sporadic, occasional employees hired for a specific service, as opposed to employees that we can depend on,” said Moore President Happy Craven Fernandez. She said Moore administrators had not gotten any complaints from models about working conditions.

Based on the NLRB ruling, only 13 models at the school had worked enough hours to vote on whether to join District Council 47 of the American Federation of State, County and Municipal Employees. Hankins said that seven of the 13 attended Wednesday’s meeting and all voted to unionize.

The local — which also represents white-collar city workers and zoo employees — wants to organize about 200 models who pose for art classes in the Philadelphia region, which is also home to the Pennsylvania Academy of Fine Arts and several other art schools.

Gary Kapanowski, a District 47 organizer, said he does not know of any other school in the country where nude models have organized, though he hopes that will change. “The labor movement needs to reach out to constituencies beyond the normal groups,” he said.

Hankins wants the all-women’s art school to raise its $11 hourly rate and provide its 40 to 60 models with warm, clean, safe spaces in which to work.

The Moore models said that disrobing for art school classes was hard work that requires them to hold a pose for long periods under sometimes difficult conditions. The studios at Moore and other art schools often lack private changing areas, adequate heaters and outside air, Hankins said.

“In the building where models do most of their work, there’s no fresh air coming in,” said Hankins, a model for nearly 20 years.

Cheryl Breese, 41, does not support efforts to unionize her fellow art class models. Breese, who is raising two teenagers and working on a college degree, made just $12,000 last year, but worries she would lose flexibility if the jobs were unionized.

“Most of us go into this job because of the freedom it presents,” said Breese, who does not work at Moore.