Since 1972, M&M Welding & Fabricators Inc. has been a full-service mechanical contractor. Based in Gaithersburg, Md., the firm specializes in boiler repairs, replacements, installation, re-tubes and rentals. It installs and repairs chillers and generators. M&M Welding & Fabricators Inc. renders an array of services, including backflow testing, power piping and installation of underground steam systems and storage tanks. Its list of clients comprises Fairfax County Public Schools, Department of General Services and Board of Education of Montgomery County.