I.S. EN ISO 748:2007
Superseded
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HYDROMETRY - MEASUREMENT OF LIQUID FLOW IN OPEN CHANNELS USING CURRENT-METERS OR FLOATS
Hardcopy , PDF
English
01-01-2007
03-01-2022
For Harmonized Standards, check the EU site to confirm that the Standard is cited in the Official Journal.
Only cited Standards give presumption of conformance to New Approach Directives/Regulations.
Foreword
1 Scope
2 Normative references
3 Terms and definitions
4 Principle of the methods of measurements
5 Selection and demarcation of site
5.1 Selection of site
5.2 Demarcation of site
6 Measurement of cross-sectional area
6.1 General
6.2 Measurement of width
6.3 Measurement of depth
7 Measurement of velocity
7.1 Measurement of velocity using current-meters
7.1.1 Rotating-element current-meters
7.1.2 Electromagnetic current-meters
7.1.3 Measurement procedure
7.1.4 Oblique flow
7.1.5 Determination of the mean velocity in a vertical
7.1.6 Errors and limitations
7.2 Measurement of velocity using floats
7.2.1 General
7.2.2 Selection of site
7.2.3 Measuring procedure
7.2.4 Types of float
7.2.5 Determination of velocity
7.2.6 Main sources of error
8 Computation of discharge
8.1 General
8.2 Graphical method
8.2.1 Depth-velocity-integration
8.2.2 Velocity-area integration method (velocity-contour
method)
8.3 Arithmetic methods
8.3.1 Mean-section method
8.3.2 Mid-section method
8.4 Independent vertical method
8.5 Mean-section method - Horizontal planes
8.6 Determination of discharge from surface-float velocity
measurements
8.7 Determination of discharge for variations of water level
8.7.1 General
8.7.2 Computation of discharge
8.7.3 Computation of mean water level
9 Uncertainties in flow measurement
9.1 General
9.2 Definition of uncertainty
9.3 Method of calculating the uncertainty in discharge by
measurement of velocity by current-meter
9.3.1 General
9.3.2 Contributory uncertainties
9.3.3 Example
9.3.4 Combined uncertainty
9.4 Method of calculating the uncertainty in discharge by
measurement of velocity using floats
9.4.1 General
9.4.2 Contributory uncertainties
9.4.3 Combined uncertainty in discharge
9.4.4 Example
Annex A (informative) Correction for sag, pull, slope and
temperature in measurement of cross-section
width by tape or wire
Annex B (informative) Distance measurement across the
cross-section
Annex C (informative) Corrections for wetted length of wire
when measuring depths with wire not normal to surface
Annex D (informative) Correction for drift
Annex E (informative) Uncertainties in the velocity-area
measurement
Annex F (informative) Determination of mean velocity from
float measurements
Bibliography
Describes methods for determining the velocity and cross-sectional area of water flowing in open channels without ice cover, and for computing the discharge therefrom.
| DocumentType |
Standard
|
| Pages |
60
|
| PublisherName |
National Standards Authority of Ireland
|
| Status |
Superseded
|
| SupersededBy | |
| Supersedes |
| Standards | Relationship |
| NEN EN ISO 748 : 2007 | Identical |
| EN ISO 748:2007 | Identical |
| NF EN ISO 748 : 2009 | Identical |
| ISO 748:2007 | Identical |
| NBN EN ISO 748 : 2007 | Identical |
| NS EN ISO 748 : 2ED 2007 | Identical |
| BS EN ISO 748:2007 | Identical |
| DIN EN ISO 748:2008-02 | Identical |
| UNE-EN ISO 748:2009 | Identical |
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