Equipment or pipework with an operation temperature greater than 55°C in case of metallic surfaces and 65°C in the case of non-metallic surfaces should be insulated so that the surface temperature after insulation (cold surface temperature) does not exceed 55°C.
SELECTION OF HOT INSULATION MATERIALS
The objective is to select a material, which will serve the insulation purpose at the lowest cost. This can be a complicated procedure. In addition to the factors listed careful consideration should be given to insulation thickness. On pipework, an over-specification of thickness creates a needless increase in the cost of the outer protection.
HOT INSULATION MATERIALS
Common to all these materials, it is recommended that their use be limited to conditions of 90% of the manufacturer’s limiting temperatures in order to safeguard against temperature surge at start-up operations of plant.
APPLICATION OF HOT INSULATION
Either pipe section, mattress or any flexible insulation may be used for pipework. However, practical reasons preclude the use of mattress or flexible insulation where the outside diameter of the pipe or the outside diameter of any previous layer of insulation is 200mm or less.