37 Custom construction of modular rooms and structures, ceiling structures, door structures, lighting structures and hardware support structures; installation, repair, maintenance of medical, clean room, treatment, laboratory, and surgical facilities; installation and assembly of surgical, medical and dental apparatus; installation of lighting apparatus, heating apparatus, refrigerating apparatus, drying apparatus, ventilating and air conditioning apparatus and sanitary installations; maintenance and repair of surgical, medical and dental instruments and apparatus, and maintenance and repair of lighting, heating, refrigeration, drying, ventilation, and air conditioning apparatus, and sanitary installations; construction of hospital buildings and maintenance and repair of hospital buildings; construction of modular buildings and maintenance and repair of modular buildings