F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
F16L59/00—Thermal insulation in general
F16L59/14—Arrangements for the insulation of pipes or pipe systems
F16L59/147—Arrangements for the insulation of pipes or pipe systems the insulation being located inwardly of the outer surface of the pipe