BS 7813:1995

Committees responsible
National foreword
Guide
Section 1. General
1.1 Scope
1.2 Definitions
1.3 Symbols and units
1.4 Central proving
1.5 On-line proving
Section 2. Statistical measurements
2.1 Principles of statistical measurement
2.2 Measurement procedure
Section 3. Central proving
3.1 Collection of data
3.2 Reliability of data collected and resulting values
3.3 Performance charts
3.4 Control charts and tests
3.5 Worked examples
Section 4. On-line proving
4.1 Collection of data
4.2 Reliability of data collected
4.3 Performance charts
4.4 Control charts
4.5 Worked examples
Section 5. Secondary control
5.1 Comparison between meter and tank
Tables
1 Performance chart no. 5 - Direct matrix
2 Performance chart no. 6
3 Example 5: test results for turbine meter
4 Performance chart, meter no. 310 test report, 1978
5 Meter factor for turbine meter no. 310, 1978
6 Random uncertainty of polynomial for turbine no.
     310, 1978
7 Performance chart, meter no. 310 test report 1979
8 Meter factor for turbine meter no. 310, 1979
9 Random uncertainty of polynomial for turbine no.
     310, 1979
10 Performance chart, meter no. 310 test report, 1980
11 Meter factor for turbine meter no. 310, 1980
12 Random uncertainty of polynomial for turbine no.
     310, 1980
13 Example 4 - normalizing meter factor
14 Computed uncertainty for vertical cylindrical tanks
     at 15 deg C
15 Computed meter uncertainty at 15 deg C
16 Combined values of transfer uncertainty for tank
     and meter
A.1 Distribution of the range
A.2 Limiting values E2 (n, theta), P = 0,95
A.3 Limiting values E2 (n, theta), P = 0,99
B.1 t-distribution values
D.1 For use with Dixon's test for outliers
D.2 For use with Grubb's test for outliers
Figures
1 Performance chart: K-factor versus flowrate
     [showing scatter (range) of 5 to 10 consecutive
     runs]
2 Control chart (general)
3 Performance chart no. 1
4 Performance chart no. 2
5 Performance chart no. 3, E = f(Q)
6 Performance chart no. 4 - UCC polynomial
7 Control chart no. 1
8 Control chart no. 2
9 Control chart no. 3
10 Control chart no. 4
11 Double chronometer method of pulse interpolation
12 Performance chart, turbine no. 310, 1978
13 Log (Q/v) vs. meter factor, turbine no. 310, 1978
14 Performance chart, turbine no. 310, 1979
15 Log (Q/v) vs. meter factor, turbine no. 310, 1979
16 Performance chart, turbine no. 310, 1980
17 Log (Q/v) vs. meter factor, turbine no. 310, 1980
18 Comparison of 1978 data with 1979 data, log (Q/v)
     vs. meter factor, turbine no. 310
19 Comparison of 1979 data with 1980 data, log (Q/v)
     vs. meter factor, turbine no. 310
20 Permissible change in flowrate during proving
21 Performance chart from series of on-line provings
22 K-factor (mean of 5 or 10 consecutive runs) versus
     time
23 Combined performance/control chart
24 Moving-average meter factor versus time
25 Control chart for meter operating within linear
     range
26 Chart A - meter performance curves - meter turbine
     proved with pipe prover
27 Control chart - meter operating outside linear
     range
C.1 Frequency histogram
C.2 Bell-shaped distribution curve
Annexes
A (informative) Statistical tables
B (informative) t-distribution values for 95% and 99%
     probability (two-sided)
C (informative) Normal (Gaussian) distribution
D (informative) Outlier tests
E (informative) Random uncertainty of polynomial
     approximation
F (informative) Bibliography
List of references

Acts as a guide for establishing and monitoring the performance of meters for liquid hydrocarbons, using statistical control procedures for central and on-line proving. Also gives definitions, symbols and units, tables, diagrams and annexes.

In dynamic measuring systems the performance of meters for liquid hydrocarbons will vary with changes in flow conditions, viz. flowrate, viscosity, temperature, pressure, density of product, and with mechanical wear.

This International Standard has been prepared as a guide for establishing and monitoring the performance of such meters, using appropriate statistical control procedures for both central and on-line proving. These procedures may be applied to measurements made by any type of volumetric or mass metering system.

The procedures to be followed for collecting data, on which the control limits are based, are described. An alternative method for establishing the reliability of these data is described in ISO 7278-3.

Methods are described for calculating the warning and action control limits for the charts covering the selected performance characteristics, the application of these control charts to subsequent routine measurements, and their interpretation. Worked examples are given in the appropriate central and on-line proving sections.