Scope
This Guideline identifies the tolerances and standards that will be considered acceptable performance.
CUSTODY AND ROYALTY MEASUREMENT SYSTEM AND EQUIPMENT TOLERANCES
Frequency
Not Applicable
Procedure
Meter Proving:
Min to Max deviation between trial runs 0.05%
Flow deviation 10% of Flow
Temperature deviation 0.2°F
Trial Runs 10
Meter Factor:
Deviation from current factor to initial factor for propane, butane, NGL, hexane, ASL, AXL, AL) ± 0.25%
Deviation between current factor and initial factor for AH ± 0.35%
API:
On-line densitometer vs. lab spot sample : 0.2° API or 0.0010 specific gravity
Densitometer repeatability 0.0005 kg/L
Densitometer calibrated range 0.300 to 1.100 kg/L
Temperature:
Flow Computer vs. Certified
Reference Glass Thermometer
or Electric Temperature Probe 0.2°F (0.1°C)
Pressure:
Flow Computer vs. Reference Gauge ±5 psi
Dead weight tester vs. pressure instrument ±2 psi
Pressure Gauge Accuracy 0.5% of calibrated span
Pressure Transmitter Accuracy ±0.075% of calibrated span.
Pipe Prover:
Sphere Inflation 2% to 4% of pipe prover internal diameter
Base prover volume shift between calibrations. < ±0.02%
Meter Registration Accuracy:
Computer Net vs. Instrument Net 0.005%
Thermometer Accuracy:
Electronic Temperature Probes vs. N.I.S.T. Certified Thermometer :0.2°F (0.1°C)
Certified Reference Glass Thermometer vs. N.I.S.T. Certified Glass Thermometer :0.2°F (0.1°C)