The management of the Philadelphia Museum of Art and union activists have set July 6 as the starting date for a mail election to determine whether its staff will affiliate with AFSCME District Council 47, the main bargaining unit for the city’s white-collar employees.

Organizers of the effort, which went before the National Labor Relations Board for hearings this week, said that the union and management had agreed to an NLRB-supervised process that would culminate with a vote count Aug. 6.

In an email, staff organizers at the museum called the agreement “a big win for all eligible staff.”

D.C. 47 officials said organizers submitted to the NLRB union authorization cards signed by over two-thirds of eligible employees on May 22. At the time, they asked management to voluntarily agree to the effort.

Management did not, and hired the Philadelphia law firm Morgan Lewis to represent it before the NLRB at hearings this week.

At the hearings, management initially resisted the union’s argument that all eligible employees at the museum, said to number over 250, should be represented by one unit. Management contended there should be two units if any, one for “core” employees and another for “noncore” staff.

That position was abandoned relatively quickly and the sides agreed to the current schedule for a “wall-to-wall” union representing all eligible employees, the organizers said. Workers who are furloughed as a result of the museum’s effort to shed employees, announced Wednesday, will still be eligible to vote in the election.

D.C. 47 leaders say they anticipate setting up a new local to represent the museum workforce should the drive win support.

In a note to staff earlier Thursday, Timothy Rub, museum director and chief executive, said the voting, conducted by mail, “will give each and every one of the employees within the petitioned-for unit an opportunity to participate in this process and to have their individual voices heard and their individual votes counted.”

Organizers said Thursday night that they were “heartened that furloughed workers will have a say in the future of the museum.” Museum officials said that merely reflected a legal requirement.