• AS 3778.2.4-2007

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    Measurement of water flow in open channels General - Estimation of uncertainty of a flow rate measurement (Reconfirmed 2022)

    Available format(s):  Hardcopy, PDF 1 User, PDF 3 Users, PDF 5 Users, PDF 9 Users

    Language(s):  English

    Published date:  08-06-2007

    Publisher:  Standards Australia

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    Table of Contents - (Show below) - (Hide below)

    1 - AS 3778.2.4-2007 Measurement of water flow in open channels Part 2.4: General - Estimation of uncertainty of a flow rate measur
    4 - PREFACE
    5 - CONTENTS
    6 - INTRODUCTION
    7 - 1 Scope
    7 - 2 Normative references
    7 - 3 Terms and definitions
    9 - 4 Symbols and abbreviated terms
    9 - 4.1 Symbols
    13 - 4.2 Subscripts
    14 - 5 Evaluation of the uncertainty in a measurement process
    15 - 6 Type A evaluations of uncertainty
    15 - 6.1 General considerations
    15 - 6.2 Calculation procedure
    16 - 7 Type B evaluation of uncertainties
    16 - 7.1 General considerations
    16 - 7.2 Calculation procedure
    16 - 7.3 Rectangular probability distribution
    17 - 7.4 Normal probability distribution
    17 - 7.5 Triangular probability distribution
    17 - 7.6 Bimodal probability distribution
    17 - 7.7 Assigning a probability distribution
    17 - 7.8 Asymmetric probability distributions
    18 - 8 Sensitivity coefficients
    18 - 8.1 General
    18 - 8.2 Analytical solution
    18 - 8.3 Numerical solution
    19 - 9 Combination of uncertainties
    20 - 10 Expression of results
    20 - 10.1 Expanded uncertainty
    21 - 10.2 Uncertainty budget
    23 - Annex A (normative) Step-by-step procedure for calculating uncertainty
    23 - A. 1 Dimensional and non-dimensional uncertainty
    23 - A. 2 Mathematical relationship
    23 - A. 3 Standard uncertainty
    24 - A. 4 Sensitivity coefficients
    24 - A. 5 Combined uncertainty
    24 - A. 6 Unreliable input quantities
    25 - A. 7 Expanded uncertainty
    25 - A. 8 Expression of results
    26 - Annex B (normative) Probability distributions
    28 - Annex C (normative) Coverage factors
    30 - Annex D (informative) Basic statistical concepts for use in Type A assessments of uncertainty
    30 - D.1 Mean of a set of data,
    30 - D.2 Experimental standard deviation, s, of a set of data
    31 - D.3 Degrees of freedom, ν, associated with a sample variance or standard deviation
    31 - D.4 Standard uncertainty, xu, of a sample mean based on the sample standard deviation
    31 - D.5 Standard uncertainty, xu, of the sample mean based on a standard deviation derived from past experience
    31 - D.6 Standard uncertainty, usm, of a single value based on past experience
    32 - D.7 Pooled standard deviation, spo, from several sets of data
    32 - D.8 Degrees of freedom, vpo, associated with a pooled standard deviation
    32 - D.9 Expanded uncertainty, xU, of a sample mean based on the sample standard deviation
    33 - D.10 Expanded uncertainty, xU, of a sample mean based on a standard deviation derived from past experience
    33 - D.11 Expanded uncertainty, Usm, of a single value
    33 - D.12 Tolerance interval for individual measurements
    34 - D.13 Detection of outliers
    35 - D.14 Worked examples
    42 - Annex E (informative) Measurement uncertainty sources
    42 - E.1 Categories of uncertainty sources
    42 - E.2 Calibration uncertainty
    42 - E.3 Data acquisition uncertainty
    43 - E.4 Data processing uncertainty
    43 - E.5 Uncertainty due to methods
    44 - Annex F (informative) Correlated input variables
    46 - Annex G (informative) Examples
    46 - G.1 Example 1 - A critical flow nozzle is used to measure the mass flow of air in a calibration rig
    48 - G.2 Example 2 - Comparing two flow-rates measured with the same meter
    53 - G.3 Example 3 - Computation of the uncertainty of flow measurement made by an orifice plate
    59 - G.4 Example 4 - Computation of uncertainty in a flow (discharge) measurement made by a velocity- area survey using a current meter
    61 - G.5 Example 5 - Computation of uncertainty in a flow (discharge) measurement made using weirs and flumes
    64 - Annex H (informative) The calibration of a flow meter on a calibration rig
    64 - H.1 General
    64 - H.2 Calibration rig uncertainty
    64 - H.3 Use of the calibration rig
    67 - Annex I (informative) Type A and Type B uncertainties in relation to contributions to uncertainty from “random” and “systematic” sources of uncertainty
    68 - Annex J (informative) Special situations using two or more meters in parallel
    70 - Annex K (informative) Alternative technique for uncertainty analysis
    71 - Bibliography

    Abstract - (Show below) - (Hide below)

    establishes general principles and describes procedures for evaluating the uncertainty of a fluid flow-rate or quantity.

    General Product Information - (Show below) - (Hide below)

    Committee CE-024
    Document Type Standard
    Publisher Standards Australia
    Status Current
    Supersedes

    History - (Show below) - (Hide below)

    First published as AS 3778.2.4-1990.Second edition 2001.Third edition 2007. Originated as AS 3778.2.4-1990. Third edition 2007.

    Standards Referencing This Book - (Show below) - (Hide below)

    AS 3778.3.2-1990 Measurement of water flow in open channels Velocity-area methods - Measurement by moving-boat method (Reconfirmed 2022)
    AS 2360.7.1-2001 Measurement of fluid flow in closed conduits - Assessment of uncertainty in the calibration and use of flow measurement devices - Linear calibration relationships
    AS 3778.4.5-1991 Measurement of water flow in open channels Part 4: Measurement using flow gauging structures Triangular profile weirs
    AS 3778.3.4-1990 Measurement of water flow in open channels Part 3: Velocity-area methods Collection and processing of data for determination of errors in measurement
    AS 3778.7-2008 Measurement of water flow in open channels Determination of volume of water and water level in lakes and reservoirs
    AS 3778.4.3-1991 Measurement of water flow in open channels Measurement using flow gauging structures - Round-nose horizontal broad-crested weirs (Reconfirmed 2019)
    AS 2360.1.1-1993 Measurement of fluid flow in closed conduits Pressure differential methods - Measurement using orifice plates, nozzles or Venturi tubes - Conduits with diameters from 50 mm to 1200 mm
    AS 3778.2.3-2001 Measurement of water flow in open channels General - Determination of the stage-discharge relationship
    AS 3778.4.2-1991 Measurement of water flow in open channels Part 4: Measurement using flow gauging structures Rectangular broad-crested weirs
    AS 3778.4.2-1991 Measurement of water flow in open channels Part 4: Measurement using flow gauging structures Rectangular broad-crested weirs
    AS 2360.0-1993 Measurement of fluid flow in closed conduits Vocabulary and symbols (Reconfirmed 2019)
    AS 2360.6.2-1993 Measurement of fluid flow in closed conduits Volumetric methods - By volume
    AS 3778.2.2-2001 Measurement of water flow in open channels General - Establishment and operation of a gauging station
    AS 3778.4.4-1991 Measurement of water flow in open channels Measurement using flow gauging structures - V-shaped broadcrested weirs (Reconfirmed 2019)
    AS 3778.1-2009 Measurement of water flow in open channels Hydrometric determinations - Vocabulary and symbols
    AS 3778.3.1-2001 Measurement of water flow in open channels Velocity-area methods - Measurement by current-meters and floats
    ATS 4747.2-2008 Meters for non-urban water supply Specification for closed conduit meters fully charged
    ATS 4747.3-2008 Meters for non-urban water supply - Specifications for open channel meters
    AS 2360.6.1-1993 Measurement of fluid flow in closed conduits Volumetric methods - By mass
    AS 2360.7.2-1993 Measurement of fluid flow in closed conduits Assessment of uncertainty in the calibration and use of flow measurement devices - Non-linear calibration relationships (Reconfirmed 2019)
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