API MPMS 4.9.2:2005 pdf download
API MPMS 4.9.2:2005 pdf download.Manual of Petroleum Measurement Standards Chapter 4-Proving Systems Section 9—Methods of Calibration for
Displacement and Volumetric TankProvers Part 2-Determination of the Volume of Displacement and Tank Provers by the Waterdraw Method of Calibration.
6.1.1 Calibration Records
All the involved parties (witnesses) should review the Calibration Certificate Package from the previous prover calibration together with all the past maintenance records and calibration hisiory of the prover thai is available. Confirm that the identifying numbers on all the calibrated equipment (test measures, thermometers, pressure gauges etc.) to be used in the calibration correspond to their respective reports of calibration. Verify that all the temperature-indicating devices (e.g., thermometers) and pressure-indicating devices (e.g., pressure-gauges) have up-to-date certificates of calibration.
All field standard test measures to be used to calibrate the prover must have up-to-date calibration certificates, which shall be verified. An up-to-date calibration certificate for a test measure is defined in the latest edition of the API MPMS Chapter 4.7, “Field Standard Test Measures.”
In a case where infrequently used test measures, as described in API MPMS Chapter 4.7, arc requested to bc used in the calibration, this request shall be made before the date of the calibration. All the interested parties shall together determine whether the test measures to be used meet the criteria established for infrequently used test measures. Their findings shall be conclusive and binding, and shall be delivered to the owner/operator of the prover to be calibrated, in writing, before the date of the calibration.
6.1.2 Temperature and Pressure Device Verification
A certified or calibrated thennometer shall be on-site with a certificate of calibration accuracy. The certificate of calibration shall be traceable to NIST or other appropriate national metrology institutes. The certified thermometer shall be used to verify the accuracy of all the other thermometers (working thermometers) used in the calibration procedures. The certified or calibrated thermometer and the working thermometers must agree within ± 0.1°F (± 0.05°C). Alternatively, working thermometers that have been certified to have been verified at three points (e.g., high, mid and low range points) within one year and a day of the time of the prover calibration by a thermometer that has a calibration traceable to NIST or other appropriate national metrology institutes may also be used providing that all of them agree among themselves within ±0.1°F (± 0.05°C).
Electronic temperature measurement devices may be used in the calibration if there is agreement between all the represented parties. If using electronic temperature measurement devices then the requirements laid out in API MPMS Chapter 7, “Temperature Measurement”, shall be followed. As part of the requirement that the device be verified before each calibration, this verification shall be carried out against a calibrated or certified thermometer, accurate to ±0.1°F (0.05°C).
A thorough inspection of all the thermometers to be used shall be made, and care must be taken to observe any signs of mercury separation, or any other defects. Once a set of thermometers has been chosen, an on-site verification of them shall he made to determine that all their readings agree to within 0.1°F (0.05°C) of the calibrated or certified thermometer. This shall be done in a temperature stable water bath that is at the approximate temperature of the water to he used in the calibration of the prover. Any thermometers that are outside of this tolerance shall be rejected as defective. If any electronic thermometric devices are used then all the same requirements as the glass thermometers shall apply. All temperature measuring devices shall be read and recorded to the nearest 0.1°F (0.05°C).
A calibrated dial type pressure gauge. or other acceptable type of pressure device (e.g. digital pressure gauge, pressure transmitter, etc.), accurate to within 1 psi, shall be used for the waterdraw calibration providing that it has a valid certificate of calibration available on-site, which is traceable to NIST or other appropriate national metrology institutes. The definition of a valid certificate of calibration can be found in paragraph 6.7, “Temperature and Pressure Indicators”. If using an analog, dial type, pressure gauge, then before beginning the waterdraw calibration it shall be checked to see that it reads “zero” at atmospheric pressure. If a valid calibration certificate is not available for this pressure gauge, or the “zero” setting requires adjustment then a recalibra(ion of the gauge will be required. Alternatively, another satisfactoiy pressure gauge shall he obtained that has with it a valid certificate of calibration. If an electronic pressure transmitting and/or digital pressure-indicating device is being used, it shall have a valid certificate of calibration accuracy and be checked for “zero” at atmospheric pressure. If a valid certificate of calibration is not available, or any adjustments to the electronics (e.g. zero, span, gain, range, etc.) have to be macic, then a recalibration of the device shall be required. Alternatively, another satisfactory pressure device shall be obtained that has with it a valid certificate of calibration. All pressure measuring devices shall be read and recorded to the nearest one pound per square in. (1 psig).
