FREQUENCY OF EXTERNAL AND INTERNAL INSPECTIONS
Type of vessel Maximum period between 2 Type of inspection
consecutive inspections
Steam boiler 1 year External and internal,
in alternance
Hot-water boiler 2 years External
8 years Internal
Thermal fluid boiler 4 years External
Water heater 2 years External
Pressure cookers with a 1 year External and internal
quick release except for
sterilizers
Steam generator 2 years External and internal
Anhydrous ammonia tank other 2 years External
than refrigerating system
Drying roller 2 years External
Digestor 2 years External