API MPMS 2.2E:2004 pdf download
API MPMS 2.2E:2004 pdf download.Petroleum and Liquid Petroleum Products- Calibration of Horizontal Cylindrical Tanks Part 1: Manual Methods.
9.4.2 Length of the horizontal cylinder
The length of the horizontal tank (cylindrical part) Is measured at the welding of the first knuckle at four measuring points representative of the length of the tank (see Figure 2).
For each measuring point, a reference point shall be marked on the tank. The measurement of the length should be repeated at least twice, Measurements shall be read to the nearest 1 mm and shall be considered satisfactory if two consecutive readings are within 0,03 % of the length or ± 3 mm, whichever Is greater. Determine the overall length by taking the average of the two consecutive readings.
9.4.3 Head radii measurements
The radius of the knuckle shall be measured using templates or depth gauges whenever possible (see Figure 2) taking up to eight measurements around the circumference, if practical, or taken from the drawings An average of eight measurements is then computed.
NOTE Physical measurements are preferred to readings from drawings.
9.4.4 Head length measurements
The length of the head shall be measured between the weldings mentioned in 9.4.2 at at least two points (see
Figure 2).
9.4.5 Measurement of length between centre head
The total length of the tank shall be measured between each end (between centre heads). Repeat the measurements until two consecutive readings agree within a tolerance of 0.03 % of the length or 3 mm. whichever Is greater.
10 Additional measurements
10.1 Deadwood
The dimensions of the deadwood shall be measured, whenever possible, or taken from the drawings and the heights of the lowest and highest point of such deadwood measured in relation to the datum point of the tank. The measurements shall be recorded to the nearest 5 mm.
10.2 Measurement of tilt
10.2.1 Above-ground tanks
When the tank is installed above the ground, a theodolite instrument with a measunng stroke can be used to determine the tih of the tank by measuring the difference in horizontal height at the weldings, i.e. at the knuckle- weldings.
The theodolite is therefore installed at the middle of the horizontal length of the tank, a little distance from the tank. The angle to the target points on the knuckle-weldings is then measured, and used for the calculation of the tilt angle (standard survey technique).
10.2.2 Underground tanks
When the tank Is installed underground, a theodolite instrument with a measuring stick can be used to determine
the tih of the tank.
The theodolite is therefore installed at the middle of the horizontal length of the tank and the height and distance of the measuring stroke (standard survey technique) is then measured.
12 Recalibration
Tanks shall be recalibrated whenever the calibration becomes suspect or the tank becomes physically deformed, for example, due to movement off the tank foundations or as required by national regulations. Similarly. if new equipment affecting deadwood volume is fitted or deadwood is removed, the tank calibration table shall be recalculated.
13 Descriptive data
13.1 Descriptive data should be entered on the tank measurement fomi. The commonly used name for the contents of the tank is a sufficient description. If a more accurate description is desired, a hydrometer reading shall be obtained and recorded with the temperature of the sample.
13.2 Supplemental pencil sketches, each completely identified, dated and signed, will forni an important part of the field data. The sketches should show
a) typical vertical and circumferential seams,
b) number and size of plates per ring.
C) location of rings at which the thickness of the plate changes.
d) arrangements and size of nozzles and manways,
e) dents and bulges in shell plates,
f) amount of off-level from the horizontal position,
g) method used in bypassing an obstwction in the path of a circumferential measurement,
h) location of the tape path different from that shown on guide sheets, and
i) location and estimated size of a gauging shelf.
NOTE Further details can be found in annex C of ISO 7507-1:1993.
