The technical specifications for a building project normally require that some time be devoted prior to project closeout for instruction and training of the client’s building operating personnel and building engineer, who will be responsible for operating and maintaining the various building systems. Manufacturers’ operating procedures, manuals, and inventory of spare parts and attic stock should be reviewed with the client, building engineer, and the contractor installing the work. The building engineer should thus gain a general understanding of the individual systems and their interaction in the operation of the building. During the warranty and guarantee period, the contractor or applicable subcontractor may be requested to assist the building engineer further in operation and maintenance of a system, including testing, balancing, and minor adjustment. After the shakedown period and when the engineer thoroughly understands system operation, the client’s personnel assume full responsibility and deal directly with the manufacturers of various building components for maintenance. Or the client may subcontract maintenance, a normal procedure for such systems as elevators and escalators where specialty expertise in maintenance is required.