Many HVAC construction projects in and around Chicago may stop with Sheet Metal Workers Local 73 on strike.

The walkout by the 5,000-member union was announced Tuesday night on the union’s Facebook page. The most recent contract proposal from SMACNA Greater Chicago, which employs the union’s members, was rejected 544-321, the union said.

Bargaining was set to resume today.

In a post on its website, officials with the Sheet Metal and Air-Conditioning Contractors’ National Association’s Greater Chicago chapter said they were “deeply disappointed” the union has decided to strike. It notes that work operating under project-labor agreements will continue, since their terms forbid walkouts.

The association said its most recent offer was a three-year contract with 3 percent annual raises that would have brought journeyman wages up to $81.78 per hour.