Jet-Care US Laboratory is awarded American Bureau of Shipping (ABS) Service Supplier status.

Find out more in the News section.

Spectro | Jet-Care launch new sample kits for marine customers

Find out more in the News section and on the Marine Sample Kits page.

Spectro | Jet-Care confirm compliance with new hydraulic fluid sampling requirements of Airbus OIT

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Spectro | Jet-Care Updates regarding Coronavirus (COVID-19)

All our laboratories remain open - please read the latest information in the News Section of our website.


We are specialists in our field and understand the time, safety and maintenance pressures you face. Our comprehensive range of services, including oil, hydraulic fluid, fuel, debris and filter analysis, is tailored to your specific requirements so you always have the resources available when you most need them.

TAN - Total Acid Number

This test measures the acidic constituents in oils and is reported in milligrams of potassium hydroxide per gram of sample.   Oils degrade while in service, due to both acidic and basic oxidation. An increase in the acid number of a used oil is a measure of the amount of acidic substances absorbed. It is measured by determining the Total Acid Number (TAN) of the oil and the value is checked against published condemning limits. The rate of change of the TAN is more important than its absolute value. A rapid increase may be caused by excessive degradation due to oxidation, hotspots from skidding bearings, carbon seals, dirty oil ways or by top-up with a different oil.