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As a cautionary note - the
surveyor should remember that the temperatures taken at or near heating
elements may distort temperature profiles.
- Portable Electronic Thermometer
The portable electronic
thermometer (PET) is the preferred means for obtaining temperatures,
The PET should have a
calibrated range of accuracy that meets the desired temperature range
of the material from which a temperature is to be taken. For
example: a PET with a calibrated micro-circuitry accurate to 300oF/149oC
is not acceptable for asphaltic products that are stored at 350oF/177oC.
- Cupcase Thermometer
Cupcase thermometers must
remain in the oil long enough to reach the temperature of the liquid
that is being measured. With regard to liquids in which
temperature stratification may occur, the time constraints involved in
using a cupcase thermometer to profile a tank may necessitate the use
of a PET.
- Dynamic Temperature Measurement
If a temperature probe in the
shore line is used to determine the temperature for the correction of
metered quantity loaded, verify and record in the inspection report the
last two times that the probe was checked for accuracy.
- Automatic Tank Gauging and
Temperature System
In an automatic tank gauging
and temperature system is used and readings cannot be verified by
manual measurements, record in the inspection report the last two times
that the automatic system and the manual measurements were
compared. Explain on the inspection report why manual
measurements were not taken and indicate any corrections that were made
to the automatic gauges.
It may be noted that automatic
gauging systems with accuracy and/or measurement tolerances equal to or
better than manual measurements may be used for custody transfer by
mutual agreement among interested parties.
Sections
of text taken from API - MPMS Chapter 17 Marine Measurement
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