ISO 8697:1999 pdf download – Crude petroleum and petroleum products -Transfer accountability -Assessmentof on board quantity (OBQ)and quantity remaining on board (ROB).
4.3 Before taking any 080 or ROB measurements, the vessel shall be required to eliminate list. The vessers trim shall be determined and recorded.
4.4 Before taking any 080 or ROB measurements, pipelines and pumps shall be &ained. One of the vessel’s tanks shall be designated to receive the material drained from all the lines and pumps. The designated tank shall be at the end of the vessel with the deepest draught and shaM be the smallest cargo tank in which the material can be measured. The designated tank shall be gauged before and after line and pump &ainlng and the measurements recorded. The measurements obtained alter line and pump draining shall be used for the calculation of 080 or
4.5 All tanks on board the vessel that may contain 060 or ROB shall be gauged
4.6 The 060 or ROB quantities in each tank shall be measured Iron, at least lour positions.
It less than four positions are available, a note of protest shall be lodged with the vessel indicating that the vessel is inadequately equipped to allow measurement in accordance with this International Standard. In this case, the OBO or ROB quantity in each tank shall be measured from aN the available positions.
One of the positions shall be the reference gauging position as defined in the vessel’s tank capacity table.
NOTE The other positions should be those which cI3Irlement the reference gauglig position so that meawrement can be made close to the geometric centre of the tank and close to the suction in each tank.
4.7 All measurements shall be taken manually with a dip-tape and weight that is capable of measunng the material depth and overall height of the compartment, Electrical equipment shall not be used.
4.8 Measure the 080 or ROB depth by direct dipping. At the same time, measure the overall height of the tank and record It. Compare the measured overall height with the tank height, H (which shall be also recorded), given in the vessel’s capacity tables to check that the tank bottom has been reached.
It the tank bottom has not been reached, measurements from other positions are preferred. Alternatively, it may be necessary to rely on ullage(s).
NOTE Reference heights given in a vessers tank-cacity tables can significantly change during a vessers lime in commissaon It is generally the case that vessel tank capacity tables ril only Include a reference height for the reference gauging posihon The use of ullage measurement for 080 and ROB should therefore he treated with caution and oi4 used if it can be established by reference to a loaded tank condition that there has been no change in the measured reference height.
4.9 The nature of the material on the dip-weight after dipping shall be visually examined to determine if liquid or non-liquid is present in each tank, If liquid is present, a water dip shall be taken. Record the depth(s) and the nature of the material(s). If both liquid and non-liquid material coexist in the same tank, record the depth of each.
NOTE Where liquid is lying on top of solidified material, careful assessment is needed as the liquid may run down and obscure that part of the dip-weight wioch should show solidified material.
It shall be ascertained whether solidified material (for example, crude oils with high pour points or heavy residues) is present. If solidified material is present and the trim of the vessel at the time of solidification is known, this trim shall be recorded (see 5.6).
4.10 If a sufficient ad depth Is found, its temperature shall be measured and recorded.
NOTE 1 It is recommended that a portable electrical teneraturo probe be used to determine temperaties.
NOTE 2 The recorded temperature may be used If ills required to calculate oil volumes at a standard temperature, using the procedures given in ISO 911 (1 or ISO 91 ‘2 (2J.
4.11 If sufficIent 080 or ROB depth Is found, a sample shall be obtained. If a sample Is taken, this shall be recorded and reported. The sample(s) shall be retained to assist In the resolution of any dispute.
NOTE Saroples should be obtained from bquid and non-liquid material. It suf1lent material is available, sampling should be carried out in accordance with ISO 3170 (3).