API MPMS 3.1B:2001 pdf download
API MPMS 3.1B:2001 pdf download.Manual of Petroleum Measurement Standards Chapter 3-Tank Gauging Section 1B—Standard Practice for Level Measurement of Liquid Hydrocarbons in Stationary Tanksby Automatic Tank Gauging.
In certain locations, still pipes without slots (olid” or ‘nan-pertoratcd’) have been used to comply with local air pollution rcgulation.s. Solid still pipes can lead to serious emit’s in level and temperature measurements and may cause tank oserhlls. They should not be used for measurement, Alternatives to solid still pipes which meet air pollution regulations are available. kefrr to MPMS Chapter 192
3.1B,4.5.7.6 Datum Plates
Refer to MPMS Chapter 3.IA on manual tank gauging for details on installation of the datum plate.
3.1B.4.5.8 Mounting of ATGs
The ATG should he mourned securely to have minimai vertical movement with respeLl to the lank refenmec. which is the bottom corner or joint. The mounting should comply with manufacturer’s instiuctons.
3.1B,4.6 REMOTE READOUT
3,1B.4.6.1 General
The manufacturers oIATGs also make associated electronics that convert the level infui’miition into an analog or digital electronic signal. The level resolution of the transmitted signal is typically I mm lot Metric (Sb units or ‘I6 inch for US Customary units.
Provisions for signal security and transient and surge protection are set forth in Sction 3.lBlO.
3.1 B.5 General Procedures for Initial
Setting and Initial Verification of ATGs in the Field
The initial setting is the procedure by which the ATG reading is set equal to the average tank level dcccmiincd by reference manual level measurement (at a single leveli, The initial vent cation is the procedure that senIle’s or confirms that the installed accwacy of the ATG is appropriate for the intended service. It is perfonned by comparing the ATG against reference manual level measurenserns ith the liquid at three different leveLs, The ditTerences between the manual and the ATG readings should he evaluated.
3.1B.5.1 INITiAL REQUIREMENTS
Prior to initial setting or initial veiitication of a new or repaired ATG, the tank should he allowed to stand at a constant level long enough for air or vapor to he released fmm the liquid and for the tank bottom to reach a stable position as recommended in MPMS Chapter 2. “Tank Cahbration’ New tanks should be filled and allowed to stand to minimize the errors caused by initial bottom settlement. The tank miser should be turned off long enough before adjustment to allow the liquid to come to rest. The tank should be run thniugh at
least one operational cycle, tilling and emptying the tank within normal working limits of tilling and discharge rate,
For electrostatic dsargc relaxation. refer ID API Recommended Practice 2003.
3.1B.5.2 REFERENCE MANUAL LEVEL MEASUREMENT PROCEDURE
When an ATG is set to level or verified by comparison with reference manual level measurement, the manual measurements should be performed in accordance with MPMS Chapter 3. IA. Reference manual nwavurements should be performed by skilled operators.
3.1 8.5.3 REFERENCE MEASUREMENT TAPE AND WEIGHT CERTiFiCATION
The measurement tape and weight used for ATO setting or verification should be a reference master combination certified by an aci.rcditcd calibration bborakwy and traceable to a national measurement standaning tape/weight (bob) combination that has been recently compared with a certified reference tape and weight meeting the maximum permissible error limits specified in MPMS Chapter 3.1 A. The calibration corrections for the tape/weight combination should he applied.
3.1 B.5.4 EFFECT OF WEATHER
High winds, heavy rain, snow or esere storms may cause moverment of the tank shell, the ATG mounting and/or the liquid surface. ‘These movements can influence both manual and ATG readings. The effect on manual gauging may he different from that on the ATG. Setting and verification should nat be carried out during high winds or severe storms.
