More than 600 adjunct professors and lecturers at the School of the Art Institute of Chicago will become part of the school’s union following a Tuesday vote, doubling the size of the city’s first major museum union.

The Art Institute of Chicago Workers United already represents about 600 staff members at both the museum and its affiliated school. The union is represented by the American Federation of State, County and Municipal Employees, which also represents unionized museum workers at the Museum of Contemporary Art in Los Angeles and the Philadelphia Museum of Art.

According to AFSCME Council 31, adjunct professors and lecturers voted 377-33 to unionize.

When faculty members announced their intention to unionize earlier this year, many expressed frustration with what they described as low pay, precarious working conditions and inequity in access to benefits.

“We simply need better contracts,” Danny Floyd, a lecturer in the school’s visual and critical studies department, said Tuesday.

Like other lecturers who make up part of the new bargaining unit, Floyd does not receive health insurance through his work at the school, where he has taught for more than eight years.

“I’m really happy that we have power at the negotiating table as a result of this vote,” he said. “I really look forward to improving our school for my colleagues and for my students.”

In a statement provided by Director of Communications Bree Witt, the school said Tuesday it intended to bargain in good faith with the union “to negotiate an initial collective bargaining agreement that best meets the needs of all parties to the contract while allowing us to continue to deliver on our mission of providing a world-class art and design education.”

In January, Art Institute workers formed the Art Institute of Chicago Workers United after a 142-44 vote. School of the Art Institute staff members voted 115-48 in favor of the union soon after. The union includes workers such as curators, retail employees custodians and librarians at the museum and academic advisers, administrative workers and mailroom employees at the school.

Non-tenure-track faculty members will now form a third bargaining unit under the union’s umbrella. They announced their intention to unionize in May and asked school management for voluntary recognition of their union in September. After school management declined to recognize the union, workers filed for an election with the National Labor Relations Board, said Anders Lindall, a spokesperson for AFSCME Council 31.

“Our colleagues have emphatically said yes to our union,” the faculty union’s organizing committee said in a statement Tuesday. “Along with the staff at the school and museum, we’ve achieved an AICWU three-peat that sends a crystal-clear message to our president, provost and board: We know our worth, we know how critical our labor is to our institution, and we know it’s time to put it in writing.”