INSPECTION WINDOWS ON INSULATION

Corrosion and/or erosion in pipe or equipment can occur both inside and outside of the metal; Internal corrosion or erosion due to the nature of the fluid are usually monitored with probes while external reduction of thickness caused by external envinroment is monitored with ultrasonic tests.

When the equipment is insulated, even if theoretically any point should be verified, inspection windows in strategic points must be provided to verify the remaining metal thickness during the life of the plant. External corrosion under insulation (twart corrosion) occurs when water or other aggessive fluid remains in contact with the metal. The map of the inspection windows shall take into account the locations where it is easier the formation of water for condensation. Sleeperways and culverts for pipes and sumps for equipment are typical location to provide the windows.

The dimension of the windiw depends on the dimension of the device used for the ultrasonic test.

See also: twart corrosion