Any restaurants, snack shops and retail stores wishing to open at the Austin-Bergstrom International Airport will be required to include labor peace agreements as part of their proposals, after a resolution the Austin City Council approved Thursday.

The move comes ahead of expected concessionaire solicitations for a nine-gate terminal expansion that is expected to open in 2019. It will not affect current businesses in the airport, which just entered new contracts, until those contracts expire in about 10 years.

The city requirements hold that the company have an agreement with any union that might represent employees to, at minimum, prohibit boycotts and service disruptions. Such guarantees are typically negotiated in exchange for agreements about wages, work hours and other working conditions.

Dozens of unionized airport concession employees turned out to the City Council meeting in matching T-shirts to show support for the item. Requiring labor agreements to be in place would protect the concessionaires from strikes in case of bargaining disagreements, said Willy Gonzalez, chapter president of Unite Here’s Local 23.

Gonzalez estimated more than 80 percent of airport concession employees are members of the union. Most of those work for businesses operated by Delaware North, which operates about two-thirds of the airport concessions.

Council Member Delia Garza, the resolution’s sponsor, teared up as she spoke of her support for union employees.

“This is truly an economic agreement here,” she told the union members. “This action will allow you to sit at the table, to have the conversations you have to have to get your pay and provide for your families.”