What is a meter prover and why is it needed?

A meter prover is a calibrated vessel used to verify the accuracy of flow meters in custody transfer service. By displacing a known volume of fluid past the meter, the meter factor (MF) can be calculated as the ratio of true prover volume to indicated meter volume. Provers ensure measurement accuracy within 0.02-0.05% for custody transfer billing per API MPMS standards.

What is the difference between a pipe prover and a small volume prover?

A pipe prover (conventional prover) uses a large-diameter U-shaped or straight pipe loop with a displacer sphere or piston traveling between two detector switches. Displaced volumes are typically 50-5000 gallons. A small volume prover (SVP) uses a precision-machined cylinder with a piston, typically 0.1-50 gallons, requiring multiple passes to accumulate sufficient meter pulses for repeatability.

How many meter pulses are required per proving pass?

API MPMS Chapter 4 recommends a minimum of 10,000 pulses per pass for turbine meters to achieve 0.02% resolution. For Coriolis and ultrasonic meters with lower pulse resolution, 500-1,000 pulses per pass may be acceptable. Small volume provers compensate with multiple passes (typically 5-10) to accumulate total required pulses.

What repeatability is required for custody transfer proving?

API MPMS Chapter 4 requires that consecutive meter factors from a proving run agree within 0.05% (0.0005) for custody transfer applications. This means all individual run meter factors must fall within a range of 0.05% of the mean. If repeatability exceeds this threshold, the proving is considered invalid and must be repeated.

Meter Prover Sizing Calculator | Pipe Prover & SVP Design

Prover Configuration

Prover Type

Meter Type Being Proved

Flow Conditions

Minimum Flow Rate

Maximum Flow Rate

GPM

Operating Conditions

Operating Pressure

psig

Operating Temperature

°F

Fluid Type

Meter & Proving Parameters

Meter Pulse Resolution

Typical: 80-8400 pulses/bbl (turbine), 20-500 pulses/bbl (Coriolis)

Desired Repeatability (%)

API MPMS Ch. 4: 0.05% for custody transfer

Minimum Pulses per Pass

pulses

10,000 (turbine), 500-1,000 (Coriolis/ultrasonic)

Number of Proving Runs

runs

Understanding Meter Proving

What is Meter Proving?
Meter proving compares a meter's indicated volume against a known reference volume (the prover) to determine a correction factor (meter factor). The meter factor MF = V_prover / V_meter ensures custody transfer accuracy within 0.02-0.05%.

Prover Types:
Unidirectional: displacer travels one way per run
Bidirectional: displacer travels both directions
SVP: compact piston prover, multiple passes

Key Sizing Parameters:
Minimum prover volume based on required pulses and repeatability. Prover pipe diameter based on flow velocity (1-5 ft/s). Round trip time must exceed 30 seconds for pipe provers.

📚 Learn the Theory

Understand prover types, meter factor calculations, volume correction factors, and API MPMS proving standards

Read Engineering Guide →

Results

Minimum Prover Volume

gallons

Prover Volume (barrels) -

Prover Pipe Diameter -

Detector Spacing -

Total Prover Length -

Round Trip Time (max flow) -

Round Trip Time (min flow) -

Pulses per Pass -

Passes Required (SVP) -

Proving Time Estimate -

Ctsp (Temp Correction) -

Cpsp (Pressure Correction) -

Pressure Rating -

Formula

V_min = N_pulses / K_meter

V_min = Minimum displaced volume per pass

N_pulses = Required pulses per pass

K_meter = Meter K-factor (pulses/unit volume)

MF = V_prover_base / V_meter

V_base = V_prover × Ctsp × Cpsp

Standards & References

API MPMS Ch. 4
Proving Systems
API MPMS Ch. 12.2
Calculation of Petroleum Quantities
API MPMS Ch. 11.1
Temperature & Pressure Volume Correction (Table 6C)
API MPMS Ch. 5
Metering (Turbine, PD, Coriolis, Ultrasonic)

Engineering Notes

Minimum pass time: 30 seconds per pass recommended for pipe provers
Prover velocity: 1-5 ft/s through prover pipe for accurate detection
Repeatability: 0.05% for custody transfer, 0.02% for high-value products
SVP advantage: Compact size, portable; requires more passes
Bidirectional advantage: Two data points per round trip, shorter proving time
Volume corrections: Ctsp and Cpsp correct prover steel volume for operating conditions

Quick Reference — Typical Prover Sizes

4" meter, 200 GPM → 6-8" prover, ~50 gal
6" meter, 500 GPM → 10-12" prover, ~150 gal
10" meter, 2000 GPM → 16-20" prover, ~600 gal
16" meter, 5000 GPM → 24-30" prover, ~2000 gal
SVP (compact): 1-50 gallon cylinder, 5-10 passes

Meter Prover Sizing Calculator

Prover Configuration

Flow Conditions

Operating Conditions

Meter & Proving Parameters

Understanding Meter Proving

📚 Learn the Theory

Results

Formula

Standards & References

Engineering Notes

Quick Reference — Typical Prover Sizes

Related Calculators

Orifice Meter

Pipeline Hydraulics

Gas Conversions

Ideal Gas Law