For example, overhead cranes which have control equipment within the structure may appear to be perfectly
secure in an open environment and be generally weatherproof. They are seldom, if ever, completely airtight,
and exposure to extremes of hot and cold exposed conditions leads to moist air being drawn into the
internal structure causing damage from condensation. Materials in general, and especially those to be
welded, must be stored clear of the ground on suitable dunned to avoid deterioration which may affect
subsequent welding. Materials in store must be inspected regularly, preferably to a preparation-arranged programmed,
and records maintained to ensure that the inspections are carried out.