Residents are invited to the town’s annual open house Thursday from 4 to 7 p.m. Members of the public can stop by municipal offices to meet town employees, learn about town services, pick up tips about fire and electric safety and other topics, and enjoy refreshments. The open house doubles this year as a celebration of National Fire Prevention and Public Works weeks. “This gives us an opportunity to share our offices, our work, and our time with all residents — and they aren’t coming in to pay a bill, pick up a license, or pay a parking ticket. It’s all for an evening of information and family fun,” Diane Norris, assistant town manager, said in a prepared statement. Participants are asked to park in the municipal lots at the senior center or across from Town Hall. They can then ride for free on the Salem Trolley to the fire and police stations, the public library, Town Hall, the Senior Center, and the Electric Division.