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If the line is stated to be
full, a line verification should be performed. If the line is
reported to be empty, a check of line drains should be made at
available locations (preferably at the low points in the
line). If the line is partially full, then the slack volume
should be determined by conducting a line displacement.
Shore lines should be walked,
if practical, to determine whether all valves are in the proper open or
closed positions are are sealed where possible. If it proves
impossible to witness valve settings or to seal valves, record (to the
extent advised by the terminal), the status of valves in the loading
system. If this task cannot be accomplished, note the reason
for non-verification and identify the tanks used in loading the
vessel. Record the findings in the inspection report and
issue a letter of protest.
When non-dedicated loading
lines are used, determine optimal loading sequences of products flowing
through the lines in order to minimize the potential for contamination
caused by line displacement. This determination should
include an agreement on how the lines will be displaced and/or how the
different product interfaces will be handled.
Before loading, each product in
the shore tanks must meet the quality specifications of all contractual
agreements and governmental agencies for both load port and
disport. Sampling and laboratory analysis shall be used to
ensure that quality specifications are met.
I addition to causing
off-specification of petroleum products, contamination may result in an
unsafe condition for terminal and/or the vessel.
If the shore line contains
material that requires heat, then it should be noted in the inspection
report whether the shore lines are insulated and if they are stem
traced and the line temperature should be obtained whenever possible
and recorded.
- Tank Gauges
Take opening gauges,
temperatures, samples and water measurements of each tank to be used in
the loading. Obtain the reference height from the tank
calibration tables before gauges and water cuts are taken.
Any difference between the observed reference height and the reference
height shown on the tank calibration tables should be noted and
investigated. Ullage and innage measurements should be taken
for purposes of comparison. The results of the investigation
will indicate which gauges should be used for volume
determination. The heavy nature of some products may require
that an outage measurement be taken. Products with densities
heavier than water may need to be water cut on top of the product.
Any incrustation that forms on
top of the product may produce inaccuracies in measurement.
If this condition exists, all parties should be notified and the
condition should be documented in the inspection report. If
the tank has been in active service recently and if time permits, wait
for the liquid level to reach equilibrium conditions. If
waiting is impossible, the inspection report should indicate how long
the cargo remained in the tank before gauging. Record the
automatic gauges for the purposes of comparison.
All gauges should be recorded
only after securing two identical measurements that have been read to
the nearest 1/8 inch (0.01 foot or 3 mm). In the case of
tanks with floating roofs, gauging should be avoided while the roof is
in the critical zone. The placement of roof legs in high or
low position and the critical zone should be noted in the inspection
report.
Sections
of text taken from API - MPMS Chapter 17 Marine Measurement
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