Probably the next question that might arise is to how does an air compressor get fuel for explosion? It is to note that most of the ships use oil lubricated compressors and it is the lubrication system of these compressors that provide the necessary fuel for a probable explosion. One more potent source of fuel is the carbon deposits that are created when the oil heats up at high temperatures.
The last and the most easily producible factor - the heat source, can be generated due to variety of reasons.
The most common source of heat source is heat generated due to friction between two surfaces. Lack of proper lubrication is the most common cause for heat generated in this way. However, lack of lubrication can also be due to degradation of lubricating oil, faulty lubricating oil pump, chocked oil filter, worn out parts etc. These are the prime reasons for the developments of hot spots.
The lack of lubrication will increase the wear and tear of the moving parts of the compressor, deteriorating the quality and operation of the compressor. As the components continue to operate poorly, carry over of the oil to the air passages takes place, increasing the temperature of that area. Also, it is very important to remove this heat generated. If proper steps are not taken to remove the heat, heat build up will take place increasing the temperature substantially. Inter-coolers play an important role in this heat removal and thus need to be properly working.