BS EN 12405-3:2015
$215.11
Gas meters. Conversion devices – Flow computer
| Published By | Publication Date | Number of Pages |
| BSI | 2015 | 82 |
Part 3 of this European Standard specifies the requirements and tests for the construction, performance, safety and conformity of flow computers (FCs) used to meet the metrological and technical requirements of a high accuracy volume conversion device.
They are used to determine volume of fuel gases, including those of the first and second families according to EN 437 .
For the purpose of this European Standard, only flow computers that are intended to operate with ultrasonic meters according to ISO 17089‑1 or gas turbine meters conforming to EN 12261 are considered.
For the purpose of this European Standard only classification classes E2 and M1 are considered for the flow computer calculator.
FCs are equipped with external separate transducers for pressure and temperature which may be approved separately.
The provisions concerning pressure and temperature transducers are given in Annex B and C.
Requirements and tests are given for energy calculator in EN 12405‑2 .
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 4 | Contents Page |
| 10 | 1 Scope 2 Normative references |
| 12 | 3 Terms, definitions and symbols 3.1 Terms and definitions |
| 18 | 3.2 Symbols and subscripts |
| 20 | 3.3 Abbreviations 3.4 Environmental classification for flow computers 3.4.1 Climatic conditions 3.4.2 Mechanical conditions 3.4.3 Electrical and Electromagnetic conditions 4 Principle of measurement 4.1 General |
| 21 | 4.2 Correction functions 4.2.1 General |
| 22 | 4.2.2 Correction of the volume at measurement conditions 4.2.2.1 General requirements 4.2.2.2 Gas meter error curve e(Qi) |
| 23 | 4.2.2.3 Gas meter definite and continuous error function δ(Q) or δ(Re) |
| 24 | 4.2.2.4 Correction procedure of the gas meter errors |
| 25 | 4.2.2.5 Limits of error correction application 4.2.3 Temperature and pressure correction of USM body dimension 4.2.4 Temperature and pressure measurement correction for conversion 5 Rated operating conditions 5.1 Specified field of measurement 5.1.1 General 5.1.2 Specified measurement range for gas pressure |
| 26 | 5.1.3 Specified measurement range for gas temperature 5.1.4 Gas characteristics 5.1.5 Base conditions 5.2 Environmental conditions 5.2.1 Ambient temperature range 5.2.2 Humidity range 5.3 Power supply |
| 27 | 6 Construction requirements 6.1 General 6.2 Sealing |
| 29 | 6.3 Time measuring functions 6.3.1 Clock 6.3.2 Time interval |
| 30 | 6.4 Casings 6.5 Indications 6.5.1 General |
| 32 | 6.5.2 Electronic indicating device 6.6 Inputs for volume conversion |
| 33 | 6.7 Alarms in flow computer 6.7.1 Detection of defective operation situations 6.7.2 Handling of volumes during maintenance 6.7.3 Memorization of metrological data 6.7.4 Handling of alarms 6.8 Specific monitoring functions performed by flow computer 6.8.1 General |
| 35 | 6.8.2 Turbine Meter health check (Mechanical meter) 6.8.2.1 Pulse – pulse comparison/Volume Comparison |
| 36 | 6.8.2.2 Pulse – Encoder comparison 6.8.3 USM health check (meter integrity check) 6.8.3.1 Verifying USM data |
| 37 | 6.8.3.2 Timeout check 6.8.4 Gas analysis devices health check 6.8.4.1 Verifying analysis data 6.8.4.2 GC-GC comparison |
| 38 | 6.8.4.3 Timeout check 6.8.5 p-T transducer health check 6.8.5.1 Verifying measurements 6.8.5.2 Timeout check for transducers 6.8.5.3 Cross check of measurements 6.8.6 Self check of the Z algorithm 6.8.7 Volume comparison 6.8.7.1 Meter – Meter comparison (serial meter connection) |
| 39 | 6.8.7.2 Meter – Meter comparison via Z-switching 6.8.7.3 Meter – Meter comparison via parallel operation |
| 40 | 6.8.8 Gas quality comparison 6.8.8.1 Speed of sound comparison between USM and GC 6.9 Cut-off function 6.10 Long-term data storage 6.10.1 General |
| 41 | 6.10.2 Categories of data to be stored 6.10.3 Triggers and methods for storage |
| 42 | 6.10.4 Clock-time stamps 6.10.5 Security (physical, electronic and software) |
| 43 | 6.10.6 Error handling 6.10.7 Long term data storage – Security audit |
| 44 | 7 Installation requirements 7.1 General |
| 45 | 7.2 Calculator 7.3 Temperature transducer 7.4 Pressure transducer |
| 46 | 8 Performance 8.1 Reference conditions 8.2 Rated operating conditions 8.3 Maximum permissible errors 8.3.1 General |
| 47 | 8.3.2 Global approach: error of main indication 8.3.3 Modular approach: specific errors for a FC 8.4 Conditions of matching the constituent elements of a FC |
| 48 | 8.5 Influence factors 8.6 Disturbances 8.7 Durability 8.8 Repeatability 8.9 Reliability |
| 49 | 8.10 Adjustment and calibration of the transducers 9 Tests of conformity 9.1 Verification of the construction requirements |
| 50 | 9.2 Verification of the performance requirements 9.2.1 Test conditions |
| 51 | 9.2.2 Samples of FC required for testing |
| 52 | 10 Marking |
| 53 | 11 Installation and operating instructions |
| 54 | Annex A (normative) Type test A.1 General conditions A.1.1 General A.1.2 Additional conditions specific to FC |
| 55 | A.1.3 Test procedures A.1.3.1 Test procedure 1 (PR1) A.1.3.2 Test procedure 2 (PR2) |
| 56 | A.1.3.3 Test procedure 3 (PR3) A.1.3.4 Test procedure 4 (PR4) A.1.3.5 Test procedure 5 (PR5) A.1.4 Verification of the construction requirements A.2 Accuracy tests under reference conditions A.2.1 Objective A.2.2 Reference to documents A.2.3 Procedure |
| 57 | A.2.4 Acceptance criteria A.3 Effect of ambient temperature A.3.1 Objective A.3.2 Reference to documents A.3.3 Procedure A.3.4 Acceptance criteria A.4 Effect of damp heat, steady-state test A.4.1 Objective A.4.2 Reference to documents A.4.3 Procedure |
| 58 | A.4.4 Acceptance criteria A.5 Effect of damp heat, cyclic test A.5.1 Objective A.5.2 Reference to documents A.5.3 Procedure A.5.4 Acceptance criteria A.6 Electrical power variation A.6.1 Objective |
| 59 | A.6.2 Reference to documents A.6.3 Procedure A.6.4 Acceptance criteria A.7 Short time power reductions A.7.1 Objective A.7.2 Reference to documents A.7.3 Procedure A.7.4 Acceptance criteria |
| 60 | A.8 Electrical bursts A.8.1 Objective A.8.2 Reference to documents A.8.3 Procedure A.8.4 Acceptance criteria A.9 Electromagnetic susceptibility A.9.1 Objective A.9.2 Reference to documents A.9.3 Procedure A.9.4 Acceptance criteria |
| 61 | A.10 Electrostatic discharges A.10.1 Objective A.10.2 Reference to documents A.10.3 Procedure A.10.4 Acceptance criteria A.11 Overload of pressure (only for pressure transducers) A.11.1 Objective A.11.2 Reference to documents A.11.3 Procedure |
| 62 | A.11.4 Acceptance criteria A.12 Effect of vibrations A.12.1 Objective A.12.2 Reference to documents A.12.3 Procedure A.12.4 Acceptance criteria A.13 Effect of shocks A.13.1 Objective A.13.2 Reference to documents A.13.3 Procedure |
| 63 | A.13.4 Acceptance criteria A.14 Overload of pressure (mechanical) (only for pressure transducer) A.14.1 Objective A.14.2 Reference to documents A.14.3 Procedure A.14.4 Acceptance criteria A.15 Durability A.15.1 Objective A.15.2 Reference to documents A.15.3 Procedure |
| 64 | A.15.4 Acceptance criteria A.16 Alarms operation A.16.1 Objective A.16.2 Reference to documents A.16.3 Procedure A.16.4 Acceptance criteria |
| 65 | A.17 Repeatability A.17.1 Objective A.17.2 Reference to standards A.17.3 Procedure A.17.4 Acceptance criteria A.18 Short time DC power variations A.18.1 Objective A.18.2 Reference to standards A.18.3 Procedure A.18.4 Acceptance criteria |
| 66 | A.19 Surges on supply lines and/or signal lines A.19.1 Objective A.19.2 Reference to standards A.19.3 Procedure A.19.4 Acceptance criteria A.20 Power frequency magnetic field A.20.1 Objective A.20.2 Reference to standards A.20.3 Procedure A.20.4 Acceptance criteria |
| 67 | Annex B (normative) Pressure transducers B.1 Scope B.2 Rated operating conditions B.2.1 Specified measurement range for pressure B.2.2 Environmental class B.2.3 Power supply B.3 Construction requirements B.3.1 General B.3.2 Casings B.3.3 Indications B.3.3.1 General |
| 68 | B.3.3.2 Electronic indicating device B.4 Performances B.4.1 Reference conditions B.4.2 Rated operating conditions B.4.3 Maximum permissible errors B.4.4 Influence factors B.4.5 Disturbances B.4.6 Durability |
| 69 | B.5 Tests of conformity B.5.1 Test conditions B.5.2 Tests B.5.3 Sample of pressure transducers required for testing B.6 Marking |
| 70 | Annex C (normative)Temperature transducers C.1 Scope C.2 Rated operating conditions C.2.1 Specified measurement range for temperature C.2.2 Environmental class C.2.3 Power supply C.3 Construction requirements C.3.1 General C.3.2 Casings C.3.3 Indications C.3.3.1 General |
| 71 | C.3.3.2 Electronic indicating device C.4 Performances C.4.1 Reference conditions C.4.2 Rated operating conditions C.4.3 Maximum permissible errors C.4.4 Influence factors C.4.5 Disturbances C.4.6 Durability |
| 72 | C.5 Tests of conformity C.5.1 Test conditions C.5.2 Tests C.5.3 Sample of temperature transducers required for testing C.6 Marking |
| 73 | Annex D (normative)Requirements and testing of meter error correction D.1 General D.2 Verification of the volumetric flow rate determination D.3 Verification of the gas density calculation procedure |
| 74 | D.4 Verification of the gas viscosity calculation procedures D.5 Verification of the error transposition from e(Qi) to e(Rei) |
| 75 | D.6 Verification of the error function δ(Q) or δ(Re) interpolation or approximation D.7 Verification of correction factor F(Q) or F(Re), corrected flow rate and corrected volume determination D.8 Verification of the activation and deactivation of error correction calculations on limits of its application D.8.1 with error correction based on flow rate Q calibration D.8.2 with error correction based on Re calibration |
| 76 | Annex E (informative) Range of application of meter error correction with functions: e(Q) or e (Re) E.1 General E.2 Range of application |
| 77 | E.3 Example for turbine meters working at pop nearly constant |
