API MPMS 2B-2002 pdf free download

API MPMS 2B-2002 pdf free download.Manual of Petroleum Measurement Standards Chapter 2-1 Tank Calibration Section 2B- Calibration of Upright Cylindrical Tanks Using the Optical Reference Line Method.
2.2B.1 Introduction The optical reference line method (ORLM) is an alternative method to the manual tank strapping method (MTSM) for determining tank diameter. The primary difference between the ORLM and the MTSM is the procedure for determining tank diameter at shell courses other than the bottom course. The ORLM provides for measuring a reference diameter on the bottom course by manual strapping and measuring deviations in tank diameter at other predetermined horizontal and vertical stations by using an optical device. The other required special measurements. procedures, methods. and analytical tools for the development of a tank capacity table are identical to those stated in API Standard 2550. 2.2B.2 Scope This standard describes measurement and calcula- tion procedures for determining the diameters of up- right welded (lap/butt) cylindrical tanks, or vertical cylindrical tanks, with a smooth outside surface and either floating or fixed roofs. This standard should be used in conjunction with AP1 Standard 2550. For external application of the ORL .M on insulated tanks, the insulation must be removed. The ORLM may be used on the interior of the tank; however, when the reference circumference on the bottom course is established exterally, the insulation al the bottom ring must be removed. This measurement shall conform to the procedures described in API Standard 2550. Abnormally deformed tanks (that is, tanks that are dented or have other visible signs of damage) should be repaired before any calibration is undertaken.
2.2B.3.3 The offset is the measurement observed through an optical device on the horizontal scale of a traversing magnetic trolley at each vertical station. 2.2B.3.4 The reference offset is the measurement observed through an optical device on the horizontal scale of a traversing magnetic trolley at the vertical station on the bottom plate. 2.2B.3.5 The reference circumference is the circum- ference of a tank measured by the MTSM on the bottom ring. 2.2B.3.6 The reference radius is the reference cir- cumference divided by 2π, where π= 3.141593. 2.2B.3.7 An optical device is an optical plummet or a theodolite equipped with a precision level. 2.2B.4 Referenced Publications The following publications are referenced in this chapter: API Std 2550 Measurement and Calibration of Upright Cylindrical Tanks (ANSI/ASTM D 1220) Manual of Petroleum Measurement Standards Chapter 1, “Vocabulary” 2.2B.5 Significance Accurate tank circumference/radius measurements are critical in determinations of liquid volume. These measurements are infuenced by both random ertors associated with physical measurements and systematic errors associated with the particular device and/or procedure used.
2.2B.7.4 CALIBRATION PROCEDURES The calibration measurements may be taken with any fll height of liquid in the tank. No transfer or mixing of the liquid shall occur during the calibration. The temperature and the relative density or API gravity of the liquid and the height of the liquid shall be recorded prior to the calibration procedure. Measure- ments shall proceed in the following manner:， a. The reference circumference shall be measured using a master tape. The reference circumference shall be measured at or very near the height of the first vertical station on the bottom ring (where the reference offset shall be measured as shown in Figure 2). The procedures given in API Standard 2550 shall be fol- lowed for the reference circumference measurement. b. The optical device shall be verified as being in a stable position. At any given horizontal station, the device should not move or be disturbed during the traverse of the magnetic trolley from the bottom ring to the top.