PROCESS & CONTROL SYSTEM DYNAMIC MEASUREMENTS
GENERAL REQUIREMENTS
6.1 Reference Conditions
All observed liquid volumes shall be corrected to the reference temperature and
pressure appropriate for the system of units. The use of these conditions are
defined in Procedure No. 1 – Definition of Reference Units and Standard
Conditions.
6.2 Volume/Mass Measurement
Hydrocarbon measurements may be either in volumetric or mass units. Volume
shall normally be used for stand-alone tanker loading operations. Depending on
the system requirements, volume or mass may be utilized for multi-facility
pipeline or offshore pipeline with an allocation requirement.
Where the measurement is in volume units, these shall be referred to standard
reference conditions such as 60°F or 15°C temperature. The metering system
shall compute inferred volumes by means of individual meter temperature
compensation and totalizers.
Mass measurement and reporting shall be achieved either by:
a) Measurement of volumetric flow rate (for example, by turbine or ultrasonic
meter) and fluid density. Mass flow rate shall then be computed as the
product of this density and the measured volume.
b) Direct mass measurement by Coriolis meter or similar.
6.3 Volume Correction
Volumes shall be corrected to reference conditions using factors determined from
the standards published by the American Society of Testing and Materials
(ASTM) and/or the American Petroleum Institute (API) Manual of Petroleum
Measurement Standards (MPMS).
Refer to SAES-Y-103 for selection of volume correction standards by product
and service type.