API MPMS 2.2D-2003 pdf free download

API MPMS 2.2D-2003 pdf free download.Manual of Petroleum Measurements Standards Chapter 2—Tank Calibration Section 2D—Calibration of Upright Cylindrical Tanks Using the Internal Electro-optical Distance Ranging Method.
5.1 ELECTRO-OPTICAL DISTANCE-RANGING INSTRUMENT 5.1.1 The angular measuring part of the instrument shall have an angular graduation and resolution equal to or better than ± 0.0002 gon*, a repeatability equal to or better than ± 0.0005 gon, and an uncertainty equal to or better than ± 0.001 gon. 2 . 5.1.2 The distance-measuring part of the instrument, used for direct determination of the distances, shall have a gradua- tion and resolution equal to or better than ± 1 mm, a repeat- ability equal to or better than ± 2 mm, and an uncertainty equal to or better than ± 2 mm. 5.2 INSTRUMENT MOUNTING consisting of a tripod which is Þrm and stable. The legs of the tripod shall be held Þrm, and steadied by suitable devices such as magnetic bearers. 5.3 LASER BEAM EMITTER having a low-power laser beam complying with IEC 825, which is either an integral part of the EODR instrument or a separate device. If the laser beam emitter is a separate device, it may be Þtted with a Þber optic light transmitter system and a theodolite telescope eye- piece connection, by which the laser beam may be transmit- ted through a theodolite, or such that it may be Þtted to a theodolite with its axis parallel to the axis of the theodolite. The laser beam may be coincident with the optical axis of the telescope Note 1: The laser beam emitter is used to position target points on the tank shell. 5.4 STADIA a rigid bar, usually 2 m long, such that the graduated length between the two stadia marks remains con- stant to within ± 0.02 mm. 5.5 EQUIPMENT FOR BOTTOM CALIBRATION (see 11.1) 5.6 AUXILIARY EQUIPMENT including: a. heavy weights to be set around the instrument to steady the unit; b. lighting within the tank, if required.
6.3 Calibration shall be carried out without interruption. 6.4 The EODR instrument shall be veriÞed prior to calibration. The accuracy of the distance-measuring unit as well as the angular measuring unit shall be veriÞed using the procedures recommended by the manufacturer. The appropriate procedures given in Appendix A shall be used for the veriÞcation of equipment in the Þeld. 6.5 The tank shall be free from vibration and airborne dust particles. Note 3: The ßoor of the tanks should be as free as possible from debris, dust and loose scale. 6.6 Lighting, when required, shall be placed within the tank so as not to interfere with the operation of the EODR instrument. 7 EODR Instrument Setup Within the Tank 7.1 INSTRUMENT SETUP 7.1.1 The instrument shall be set up with care, according to the procedure and instructions given by the manufacturers. 7.1.2 The instrument shall be set up so as to be stable. If necessary, the tank bottom in the vicinity of the instru- ment shall be made Þrm and steady by placing heavy weights in the area. The legs of the tripod on which the instrument is mounted shall be steadied by use of suitable devices, such as magnetic bearers, to prevent slippage on the tank bottom. 7.1.3 The instrument shall be located at, or near, the center of the tank. Note 4: This will ensure that the measured slope distances, at any one horizontal level, do not vary signiÞcantly and minimizes the overall uncertainty of slope distance determination. 7.1.4 The instrument shall be set horizontal, thus ensuring that the vertical axis (standing axis) is vertical.
7.2.3 The slope distances to each of the two reference target points shall be measured. Two successive readings to each ref- erence target point shall be taken. The two readings, at each point, shall agree within ± 2 mm. The average distance to each point shall be calculated. The slope distances shall be recorded. 7.2.4 Wait 15 min and repeat 7.2.3. The repeated slope dis- tances shall agree within ± 2 mm with the slope distances originally measured. The slope distances shall be recorded. 7.2.5 If the original and repeated average slope distances do not agree within ± 2 mm, determine the reason for the difference. a. If the reason for differences is due to the instrument and or its stability, repeat the procedure from 7.1. b. If the instrument was switched off during the determina- tion of the differences, repeat the procedure from 7.2.1. c. If neither a) nor b) is appropriate, repeat the procedure from 7.2.3 d. Repeat the appropriate procedures until two successive readings agree within ± 2 mm. 8 Selection of Target Points 8.1 Select two sets of target points per course, one at 1 / 5 to 1 / 4 of course height above the lower horizontal seam, the other at 1 / 5 to 1 / 4 of course height below the upper horizontal seam. The number of target points per set, on each course of the tank shell wall, is dependent on tank circumference. The min- imum number of target points per set, as a function of tank circumference, is given in Table 1 and illustrated in Figure 1. 8.2 The target points shall be at least 300 mm from any ver- tical welded seam.