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 Internal measurements
9.1 General
For the measurement procedures, a telescopic rod (5.2) of sufficient length to completely measure the internal diameter of the tank shall be used. The internal method is applicable to tanks less than 4 m in diameter.
In all cases, the telescopic rod shall be applied to the tank at the prescribed locations, at four positions, equally divided around the circumference. The average of these four measurements shall be recorded.
9.2 Repetition of measurements
After an internal diameter has been measured, the telescopic rod shall be released and brought back again to the
tank shell. The readings shall be repeated and recorded.
9.3 Tolerances
Measurements shall be read to the nearest 1 mm and shall be considered satisfactory if they are within 0,05 % of the diameter or ± 1 mm, whichever is greater.
If agreement is not obtained, further measurements shall be taken and recorded until two consecutive averages agree. The overall average of these two averages shall be taken as the diameter. If consecutive measurements do not agree, the reason for the disagreement shall be determined and the calibration procedure shall be repeated.
9.4 Other measurements on tank-shell plates
9.4.1 Plate thickness
The plate thickness shall either be measured for each course, whenever possible, or will be taken from the drawings. The plate thickness for each course shall be recorded to the nearest 0,5 mm. Physical measurements are preferred to readings from drawings.
NOTE The thickness Is required tot pressure correction,
9.4.2 Length of th. 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 measunng 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 prectical, or taken from the d.awings. An average of eighl 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 heeghts 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 measuring stroke can be used to determine the tilt 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 rnstalled underground, a theodolite instrument with a measuring stick can be used to determine the tilt 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.