Building maintenance and repair; Construction and maintenance of buildings; Construction project management services in the field of mechanical systems, plumbing systems, pipefitting, code welding, HVAC systems, ammonia systems, and refrigeration systems; HVAC contractor services; Mechanical contractor services; Plumbing and gas and water installation; Plumbing contractor services; Plumbing installation advisory services; Plumbing maintenance advisory services; Plumbing repair advisory services; Advisory services relating to the construction of buildings; Advisory services relating to the installation of plumbing; Advisory services relating to the maintenance of plumbing; Advisory services relating to the repair of plumbing; Building construction; Contractor services, namely, review of and remedial recommendations for building plumbing, electrical and mechanical systems for others; General construction contracting; Heating contractor services; Installation of HVAC systems; Installation of plumbing systems; Installation, maintenance and repair of refrigerating apparatus; Maintenance of plumbing; Maintenance of the mechanical systems, plumbing systems, HVAC systems, ammonia systems, and refrigeration systems in buildings; Maintenance of the mechanical systems, plumbing systems, HVAC systems, ammonia systems, and refrigeration systems in commercial and industrial buildings