All of the elastic compounds present a permeability to gases at different levels. The pressured gas penetrates below the O-Ring surface forming air pockets in the intermolecular spaces. The quantity of gas absorbed depends on the type of compound and of the gas in contact with it, from the temperature and the exercise pressure. The instance described above can be the cause of damage to the O-Ring, if it is followed by an abrupt reduction in pressure and the consequent dilating of the ring, the gas included in the compound has an explosive behaviour. The explosion of the air pockets present in the compound provokes the laceration of the O-Ring surfaces. The effect of an explosive decompression on an O-Ring is shown in figure 9.6.
Damaged by explosive decompression