API MPMS 17.7:1995(R2012) pdf download.Manual of Petroleum Measurement Standards Chapter 17—Marine Measurement
This procedure is intended to determine a fixed barge/shore ratio which can be used either when no reliable Vessel Experience Factor (VEF) is available or to verify and validate an existing VEF. The resultant ratio may be used as a ÒControl FactorÓ to ascertain a corrected barge volume for comparison against future shore delivery or receipt volumes. This procedure describes the method for determining the volume ratio of a barge relative to an accurate known volume, measured by shore tank or meter; this will be known as the Control Factor. The procedures and practices relate to action by buyers, sellers, shore terminal operations, barge owners, independent inspectors, and other parties having an interest in the measurements. If the methods stated in this procedure are followed, the measurements will form a reli- able basis for comparing relative shore and barge volumes in the production of a Control Factor. The procedures contained in this method apply to a single transfer between the shore and the barge, preferably using a light or medium product or chemical with an approximate volume of at least 80 percent fill of the barge capacity. The procedure may be conducted again at a later date for added assurance or to update the factor for any structural change(s) or damage to the barge. This method is not a substitute for, nor does it replace, barge calibration (strapping) tables or the need for recalibra- tion. The gauging procedures outlined herein and known as ÒDouble Reference GaugingÓ may also be employed in regular inspection of barge and shore quantification as a loss control technique. This method is intended for inland waterway barges. Ocean-going barges should use VEF method.
The use of a large tank will decrease the accuracy due to the gauging tolerance when a relatively small volume is transferred from a large tank. Select a tank size that is suit- able for test volume. To ensure accuracy in uncertainty better than 0.20 percent of the volume, a single shore tank should be used that has sufficient volume to conduct the test: one that allows a minimum of 2 meters (about 6 feet) of tank volume to be transferred to the barge. However, the level remaining in the tank on completion of the test should be at least 2 feet above the top of the main tank outlet pipe. Prefer- ably, the tank should be more than half full prior to the test. The tank bottom should be stable, and have no known appreciable flexing. Flexing in excess of 15 millimeters (about 1 Ú 2 inch) may not be suitable for use in development of a B.C.F. Check any available records and inquire of terminal experience with variance in total gauge height.