BS ISO 7507-3:2006 pdf download.Petroleum and liquid petroleum products ——Calibration of vertical cylindrical tanks—— Part 3: Optical-triangulation method.
11.3.4 Leaving the tripod supports in the same position, interchange the stacha (or prism) and the theodolite. so that the stadia (or prism) is at location Ti and the theodolite is at location T2.
Repeat the determinations descnbed in 11.3.2 and 11.3.3.
11.3.5 The value tar D obtained In 11.3.2 shall agree with that obtained In 11.3.4 withIn the tolerances given in 12.1. If agreement is not obtained, repeat the measurements, starting at station Ti • until two consecutive values do so agree. Record the arithmetic mean of the two values as the horizontal distance Ti to T2.
11.3.6 Transfer [tie tripod set up at Ti to T3, leaving the tripod set up at T2 In place. Apply the procedure in
11.3.2 to 11.3.4 for locations Ti and T2 to locations T2 and T3.
11.3.7 Continue th€ procedures for all subsequent stations around the circumference until station TI is reached again.
11.3.8 For each course, repeat the procedure described in 11.3.2 to 11.3.7 at two levels, one at about 114 of the course height above the lower horizontal seam and the other at about 1,4 of the course height below the upper horizontal seam.
12 Tolerances
12.1 Distances between theodolites
The measurements of the distance, D, between the two theodolile stations taken before and after other optical readings shall not chffer by more than the tolerances given in Table 3.
Repeat the determinations descnbed in 11.3.2 and 11.3.3.
11.3.5 The value tar D obtained In 11.3.2 shall agree with that obtained In 11.3.4 withIn the tolerances given in 12.1. If agreement is not obtained, repeat the measurements, starting at station Ti • until two consecutive values do so agree. Record the arithmetic mean of the two values as the horizontal distance Ti to T2.
11.3.6 Transfer [tie tripod set up at Ti to T3, leaving the tripod set up at T2 In place. Apply the procedure in
11.3.2 to 11.3.4 for locations Ti and T2 to locations T2 and T3.
11.3.7 Continue th€ procedures for all subsequent stations around the circumference until station TI is reached again.
11.3.8 For each course, repeat the procedure described in 11.3.2 to 11.3.7 at two levels, one at about 114 of the course height above the lower horizontal seam and the other at about 1,4 of the course height below the upper horizontal seam.
12 Tolerances
12.1 Distances between theodolites
The measurements of the distance, D, between the two theodolile stations taken before and after other optical readings shall not chffer by more than the tolerances given in Table 3.
