Some cargoes must be kept from commingling, and in some cases to provide for an extra margin of safety, two isolation valves are closed between the incompatible cargoes so contamination cannot occur.

Related Terms


Any loss of performance due to the presence of contamination. Two basic types of contamination failure are: Perceptible - gradual loss of efficiency or performance, and Catastrophic - dramatic, unexpected failure.


A broad subject which applies to all types of material systems (including both biological and engineering). It is concerned with planning, organizing, managing, and implementing all activities required to determine, achieve and maintain a specified contamination level.


Oil-insoluble materials that result from oxidation and decomposition of lube oil and contamination from external sources and engine blow-by. These can settle out on machine or engine parts. Examples are sludge, varnish, lacquer and carbon.


A fluid circulation process designed to remove contamination from the wetted surfaces of a fluid system.


Passage of unburned fuel and combustion gases past the piston rings of internal combustion engines, resulting in fuel dilution and contamination of the crankcase oil.


A method of analysis whereby the dry weight of contaminant per unit volume of fluid can be measured showing the degree of contamination in terms of milligrams of contaminant per liter of fluid.


A method by which a specified volume of fluid is filtered through a membrane filter of known pore structure. All particulate matter in excess of an 'average size', determined by the membrane characteristics, is retained on its surface. Thus, the membrane is discolored by an amount proportional to the particulate level of the fluid sample. Visually comparing the test filter with standard patches of known contamination levels determines acceptability for a given fluid.


The fluid system contamination level at the time of release from an assembly or overhaul line. Fluid system life can be shortened significantly by full-load operation under a high fluid contamination condition for just a few hours. Contaminant implanted and generated during the break-in period can devastate critical components unless removed under controlled operating and high performance filtering conditions.


The degree of contamination. Contamination usually expressed in ppm.


Occurs when foreign materials or impurities enter the fuel, oil or water.

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