The Zoning Board of Appeals is in the process of drafting a decision on the Parc at Medfield, a 96-unit housing complex proposed by the Gatehouse Group under the state’s Chapter 40B affordable housing law. The board has 40 days from Nov. 5, which marked the end of its public hearings on the project, to decide whether to grant the developer a permit. Plans for the Parc complex call for two buildings of 48 apartments on the site of the former Potpourri building, in an industrial zone between West Street and Route 27. Some of the units would be rented at below-market rates to income-eligible tenants. Local residents have expressed concern over the number of children the development would add to the school system, as well as the project’s effects on wetlands, and traffic and pedestrian safety. Chapter 40B limits the control that a community can exercise over projects that include affordable housing if less than 10 percent of the community’s housing stock is considered affordable. Roughly 4.4 percent of the housing in Medfield meets the state’s affordability standards.