All measurement equipment shall be maintained in optimum operating condition
at all times to ensure the accuracy and reliability of all measured values. All
measurement equipment used to calibrate, verify, or certify field measurement
equipment or systems shall be certified as to accuracy at the time of purchase
and re-certified annually or at any time the accuracy is in doubt.
PROCESS & CONTROL SYSTEM INSPECTION AND MAINTENANCE
No modifications or maintenance shall be performed on any measurement
equipment or systems that could affect the accuracy or reliability of the measured
quantity or quality without prior consultation with the Custody Measurement Unit.
11.1 Maintenance
Regular Preventive Maintenance (PM) and service shall be scheduled and
performed to ensure the accuracy and reliability of all measurement and shall be
included in the PM program.
Maintenance Departments shall maintain equipment calibrations to the guidelines
provided in Procedure No 4 –Equipment Calibration Frequency.
Critical valves and seals for metering systems shall be tested and leak checked
per Procedure No 64 – Critical Valve Seal Integrity Check
Operational and Maintenance Departments shall isolate and remove out of
tolerance custody/royalty measurement equipment. Out of tolerance equipment
used in custody/royalty service shall be red-tagged, sealed and locked from
service. The equipment shall be repaired and re-calibrated before being returned
to service per Procedure No 67 – Meters Returned to Service
11.2 Inspection
Meters shall be inspected for excessive wear, faulty or weak parts, improper
clearances, etc. per the following procedures:
Procedure No 65 – Turbine Meter Inspection
Procedure No 66- Positive Displacement Meter Inspection
Meter shall be inspected when there is an indication of performance shift as
identified in Procedure No 39 – Meter Factor Acceptance Criteria.
A Meter Inspection Report shall be completed to provide a complete description
of the condition of all parts of a meter. The technician who inspects, repairs, or
makes replacements shall prepare this report. The original of the Meter
Inspection Report shall be sent to the Custody Measurement Unit and a copy
shall be maintained with the maintenance file at the location.
11.3 Performance Monitoring
Operations and Maintenance Departments involved in the use and maintenance
of the equipment and systems are required to monitor the performance of the
measurement equipment and systems. The performance monitoring shall use
statistical quality control (SQC) methods to determine preventative maintenance,
calibration and verification activities.
Each Operating Department shall maintain a database for the purposes of
performance monitoring, maintenance planning and scheduling. For example
meter control factors shall be monitored to determine preventative maintenance,
control limits and future calibration schedules.