37 CONSTRUCTION OF INDUSTRIAL FURNANCES; INSTALLATION OF MACHINES, MOTORS, EQUIPMENT AND PRODUCTION AND MACHINING PROCESSES IN INDUSTRIAL INSTALLATIONS; CONSTRUCTION OF INSULATING SYSTEMS, LAYING PIPELINES; REPAIR AND MAINTENANCE OF ELECTRICAL, ELECTRONIC AND MECHANICAL PRODUCTS, PRECISION ENGINEERING PRODUCTS, MEDICO-ELECTRICAL EQUIPMENT, AND HEATING INSTALLATIONS; METAL WORKING; PREPARING, MAINTAINING AND INSTALLING EQUIPMENT IN THE POWER, TRANSPORTATION AND INDUSTRIAL FIELD