CURIOSITY CORNER: What do inspection report abbreviations stand for?

Upon receipt of an inspection report, have you ever wondered what all the abbreviations stand for and their significance? Why can’t there be one number reported as the bottom line quantity, which is contractually agreed upon? In fact, this is one of the most common questions we receive from newbies in the energy industry.

In the “solids” commodity world, when a truckload of televisions is delivered, the bill of lading (the amount loaded) matches up directly to what is being delivered at all points. 500 TV’s loaded… 250 delivered at point one, 100 at point two, 150 delivered at point three. Simple!

It isn’t the same in the “liquid” commodities market due to many factors that affect the final quantity before it is commercially agreed upon. We will explain abbreviations listed on final inspection reports, what they mean, and their significance in the determination of the quantity loaded or discharged.

T.O.V. – Total Observed Volume

This is everything in a tank or vessel compartment at the observed temperature. This volume includes the product, free water (FW) and sediment and water (S&W).

G.O.V. – Gross Observed Volume

This is the TOV above (everything in the tank) minus the free water, again at the observed temperature. Remember the “O” as in observed, not corrected, as these are observed volumes regardless of temperature.

G.S.V. – Gross Standard Volume

The GSV represents the Gross Observed Volume corrected to a standard temperature. In the United States, this is 60 degrees F.

N.S.V. – Net Standard Volume 

The NSV is the GSV (above) minus the sediment and water – again corrected to a standard temperature. Remember the “S” means standard – this indicates the volumes have all been corrected or standardized.

T.C.V. – Total Calculated Volume

This is the GSV with the free water added back in. It is therefore all of the product (including S&W) corrected to a standard temperature with any free water added back in. TCV is primarily a loss control tool as it looks at the complete picture of the cargo on board a vessel.

FW – Free Water

It is necessary to determine the amount of free water, if any, before and after each product movement into or out of a tank in order that the appropriate corrections can be made. This will always be in the form of a deduction. The amount of the deduction is determined by converting the free water level gauge to a volume through the use of the tank compartment’s capacity table.

S&W – Sediment & Water

The API Committee regarding Petroleum measurement prefers this abbreviation to the older BS&W (bottom sediment and water). Sediment is the matter that settles to the bottom of a liquid; also called tank bottoms.

Sediment and Water refer to material coexisting with, yet foreign to, petroleum liquid and requiring a separate measurement. This foreign material includes emulsified or suspended water and sediment. The quantity of suspended material present is determined by laboratory testing of a sample of petroleum liquid.