Contaminated Fuel Analysis

Emulsified water, freestanding water, diesel particulate, microbial growths and diesel sludge can cause significant damage to emergency generators. Modern engines are incredibly sensitive to these fuel contaminants. Engine filters can block and fuel injectors can suffer damage, resulting in total engine failure. This can have huge implications if the engine drives a generator providing emergency power to a hospital, data centre or bank. ASTM D975 indicates the importance of a plan for monitoring bulk fuel during prolonged storage. Stored fuel should be periodically sampled and its quality assessed.


The basic test package offered by Sterling Analytical Laboratory evaluates fuel samples to ensure fuel has not been exposed to harmful contaminants:

Test Required Method Indicates
Clear and Bright ASTM D4176 Visual Appearance
Water and Sediment ASTM D2709  Filter plugging/corrosion
Water by Karl Fischer ASTM D6304 Engine fouling/corrosion
Flash Point ASTM D93 Gas contamination 
Microbial Growth ASTM D6469 Filter plugging, corrosion
Particulate  ASTM D2276  Filter Plugging 

Additional testing may be required to further evaluate fuel quality:

Test Required Method Indicates
Distillation ASTM D86 Hydrocarbon Mixture
API Gravity ASTM D1298 Measured Volumes
Copper Strip corrosion ASTM D130 Protect metal parts
Asphaltenes AH-24A-ASP2 Filter Plugging
Sulfur ASTM D5453 Emissions Control
Cetane Number ASTM D976 Ignition Quality
Cetane Index ASTM D4737 Aromatic Content
Ash Content ASTM D482 Engine deposits
Viscosity ASTM D445 Injector & Pump wear
Carbon Residue ASTM D524 System Deposits