ALL LEVEL SAMPLE - An all levels sample is obtained by submerging a stoppered container to a point as near as possible to the draw-off level of a tank, then removing the stopper and raising the container at a rate such that the container is about 75% full (no more than 85%) as it emerges from the liquid.
API GRAVITY is the density of the petroleum product and may be measured by a hydrometer instrument having a scale graduated in degrees API.
AUTOMATIC GAUGING SYSTEM - An automatic gauging system is a computerized system used to determine the total gross volume in a tank.
BALLAST is the water taken on a vessel, typically when it is empty or partly loaded to increase draft, properly submerge the propeller and maintain stability and trim.
BLACK OIL / DIRTY OIL / RESIDUAL is commonly known to the industry as a heavy (low API Gravity), dark in color and viscous in texture product that typically requires heating to liquefy.
BOTTOMS are the product below the suction point in a tank.
BOTTOM SAMPLE - A bottom sample is a sample of the material obtained from the tank bottom.
BUNKER is the combustible fuel used for operating the vessel's engines and, if necessary, the heaters used for heating the cargo being transported.
CALIBRATION TABLES or CHARTS are tables that represent the volumes in each tank according to the liquid (innage) or space (ullage) measured in the tank.
CLEAN OIL is commonly known to the industry as a lighter (higher API Gravity), light in color and liquid in texture product.
CLEARANCE SAMPLE - A clearance sample is a spot sample taken 4 inches below the tank outlet level.
CLINGAGE is the cargo that adheres to all surfaces of the emptied portion of a tank other than the bottom surface.
CLOSING GAUGE is an innage or ullage measurement taken after the product is transferred into or out of a tank.
COMPOSITE SPOT SAMPLE - A composite spot sample is a blend of spot samples mixed in volumetric proportions.
For tanks with greater than 1,000 Bbls capacity, spot samples are collected in the following ways:
i. For tanks containing more than 15 FT of product, at three levels.
ii. For tanks containing between 10 and 15FT of product, at two levels.
iii. For tanks containing less than 10 feet of product, one middle spot sample at the center of the product.
CORRECTED GAUGE is the Physical. / Observed Gauge corrected by the vessel's trim.
CRITICAL ZONE is the distance from the point where a floating roof in a shore tank is resting on its normal supports to the point where the roof is floating freely.
CRUDE OIL WASHING is a method for washing tanks on a vessel. It involves the use of a high-pressure stream of the crude oil cargo to dissolve clingage and sediment from the bulkheads, bottom, and internal tank structures of a vessel during the discharge operation.
CUT - a cut is a marked line on the measuring scale made by the product or free water being measured.
DATUM PLATE is a level metal plate located on the tank bottom directly under the reference gauge point to provide a fixed contact surface from which liquid level measurement can be made.
DIRTY OIL / BLACK OIL / RESIDUAL is commonly known by the industry as a heavy (low API Gravity), dark in color and viscous in texture product that typically requires heating to liquefy.
DRAFT is a vessel's depth below the water line, measured from the surface of the water to the bottom of the vessel's keel.
DRAIN SAMPLE - a drain sample is obtained from the water draw-off valve.
FLOW PROPORTIONAL SAMPLE - a flow proportional sample is taken from a pipeline during the entire transfer. The rate of sampling is proportional to the flow of the liquid in the pipe at any instant.
FREE WATER (FW) is the volume of water that is not in suspension in the petroleum liquid. Typically found at the lower layer.
GROSS OBSERVED VOLUME (GOV)
GOV = TOV - FW
GOV is the total volume of all petroleum liquids and sediment and water, excluding free water at observed temperature.
GROSS STANDARD VOLUME (GSV)
GSV = GOV x VCF
GSV is the total volume of all petroleum liquids and sediment and water, excluding free water, corrected by the appropriate volume correction factor.
INNAGE (DIP) GAUGE - An innage (dip) gauge is the level of liquid in a tank measured from the datum plate or tank bottom to the surface of the liquid.
INNERTING is a procedure used to reduce the oxygen content of a vessel's cargo spaces to 8 % or less. This procedure is performed by introducing and inert gas such as nitrogen or carbon dioxide or a mixture of gases such as flue gas.
INTERNAL CIRCULATION METHOD - this method is applied by transferring a measured volume of liquid from one shore tank into the same tank or another shore tank containing similar product through the pipeline system designed for the inspection operation. This method is used to eliminate air or vapors from the line.
LETTER OF PROTEST is a written record of a particular action or finding that is questioned at the time of occurrence.
LINE DISPLACEMENT METHOD - This method is applied by measuring the volume of liquid pumped from a shore tank to a vessel (Load Transfer) or to a shore tank from a vessel (Discharge Transfer) through the pipeline system designated for the cargo transfer and comparing the measured volume delivered to the measured volume received. This method is used to determine the line volume condition.
LINE PRESS METHOD - This method is applied by pressurizing the contents of the designated pipeline system with product to eliminate air or vapors from the line.
LIST is the leaning or inclination of a vessel, expressed in degrees port (left side) or starboard (right side).
LOAD ON TOP is the act of loading product on top of existing cargo and commingling both products together.
LOWER SAMPLE - A lower sample is a spot sample obtained at the midpoint level of the lower third of the tank contents.
MIDDLE SAMPLE - A middle sample is a spot sample obtained from the middle of the tank contents.
MULTIPOINT GAUGING is measuring a vessel tank through two or more openings in the top of the tank.
NET STANDARD VOLUME (NSV)
NSV = GSV - S&W
NSV is the total corrected volume of all petroleum liquids, excluding sediment and water and free water.
NOTICE OF APPARENT DISCREPANCY is a written record of a significant volume difference found at the time of volume calculations and/or voyage analysis.
ON-BOARD QUANTITY (OBQ) is the material present in the vessel's cargo tanks, void spaces and pipelines before the vessel is loaded.
OPENING GAUGE is an innage or ullage measurement taken before the product is transferred into or out of a tank.
OUTLET SAMPLE - An outlet sample is a spot sample taken from the bottom of the tank outlet level, but not higher than 1 meter (39") above the bottom of the tank.
PARTIAL DISCHARGE is the act of discharging part of the cargo on board a vessel.
REFERENCE GAUGE HEIGHT is the distance from the datum plate or tank bottom to the reference gauge point. This distance should be clearly marked on the tank top near the gauge hatch and recorded in the tank's calibration table.
REFERENCE GAUGE POINT is a mark on the gauge hatch of a tank, which indicates the exact location where the gauging should be carried out.
REMAINING ON BOARD (ROB) is the material present in the vessel's cargo tanks, void spaces and pipelines after the vessel is discharged.
RESIDUAL / DIRTY OIL / BLACK OIL is commonly known by the industry as a heavy (low API Gravity), dark in color and viscous in texture product that typically requires heating to liquefy.
RUNNING SAMPLE - a running sample is obtained by lowering an un-stoppered container from the top of the product level to the bottom of the outlet connection and returning it to the top of the product at a uniform rate of speed such that the container is approximately 75% full (no more 85%) when withdrawn from the product.
SEA SUCTION VALVE is a valve used to control in take of ballast on a vessel.
SEDIMENT AND WATER (S&W) is the non-hydrocarbon solid material and water found in suspension in a petroleum product.
SINGLE TANK COMPOSITE SAMPLE - A single tank composite sample is an equal blend of the upper, middle and lower spot samples. For tanks of uniform cross section, such as an upright cylindrical tank, the blend consists of equal parts of the three samples.
SLOPS are oil, oil/water/sediment, and emulsions contained in slop tanks or designated cargo tanks. The mixture is usually a result of tank stripping and washing.
SLUDGE is a highly viscous mixture of oil, water, sediment and residue.
SPOT SAMPLE - A spot sample is a sample taken from a specific level of a tank or from a pipe at a specific time during a pumping operation.
STOP GAUGE is a pre-determined innage or ullage gauge representing a specific volume of cargo within a tank.
SURFACE SAMPLE - A surface sample is a sample skimmed from the surface of a liquid in a tank.
TANK-SIDE SAMPLE - A tank side sample is a spot sample taken from a sample connection located on the side of the tank.
TOP SAMPLE - A top sample is a spot sample obtained 6 inches below the top surface of the liquid.
TOTAL CALCULATED VOLUME (TCV)
TCV = GSV + FW
TCV is the total corrected volume of all petroleum liquids and sediment and water, corrected to a standard temperature plus all free water measured at observed temperature.
TOTAL OBSERVED VOLUME (TOV) is the total of all petroleum liquids, sediment and water, and free water at the observed temperature.
TRIM is the difference between the forward and aft drafts of a vessel, expressed by the head or by the stern.
TUBE or THIEF SAMPLE - A tube or thief sample is obtained with a sampling tube or special thief sampler from a specified point in the tank or container.
ULLAGE (OUTAGE) GAUGE - An ullage (outage) gauge is the distance from the surface of the liquid in a tank to the reference gauge point of the tank.
UPPER SAMPLE - An upper sample is a spot sample taken at the midpoint level of the upper third of the tank contents.
VESSEL EXPERIENCE FACTOR (VEF) - The VEF is a calculated value based on statistical comparisons between TCV quantities delivered or received by the Vessel, against the corresponding Shore measurements, at either load or discharge ports.
VESSEL LOAD RATIO (VLR) =Vessel Quantity Received / Bill of Lading.
VESSEL DISCHARGE RATIO (VDR) = Vessel Quantity Delivered / Outturn.
VOLUME CORRECTION FACTOR (VCF) - The VCF is a factor used for converting volumes at an observed temperature and gravity or density to a standard temperature (60 °F or 15 °C).
WALL WASH TEST is the procedure of washing selected areas of a vessel's tank interior and testing the wash liquid for the presence of material which might contaminate the cargo to be loaded.
WATER CUT MEASUREMENT is the procedure of locating the product / water interface for determining the volume of free water in a shore tank or vessel compartment.
WATER WASHING is a method for washing vessel's tanks. It involves the use of a high-pressure water stream to dissolve clingage and sediment from the bulkheads, bottom, and internal tank structures of a vessel.
WEDGE FORMULA is a mathematical formula use for calculating small amounts of liquid materials (OBQ’s and/or ROB’s) on board a vessel. The wedge formula is used when the liquid material is not in contact with all bulkheads of the vessel's tank.
WIPE TEST is the procedure of randomly wiping the interior of a vessel tank with an absorbent white rag. This procedure is used to test the tank's coating for possible color contamination on cargo to be loaded.