BS ISO 18132-3 pdf download Refrigerated hydrocarbon and non-petroleum based liquefied gaseous fuels — General requirements for automatic tank gauges Part 3: Automatic tank gauges for liquefied petroleum and chemical gases on board marine carriers and floating storage
This part of lSO 18132 establishes general principles for the accuracy, installation, calibration and verificationof automatic tank gauges (ATGs) used for custody transfer measurement of liquefied petroleum and chemicalgases on board a gas carrier or floating storage.
The part of IlSo 18132 also describes the technical requirements for data collection, transmission and reception.Specific technical requirements for various automatic tank gauges and accuracy limitations are given in the annexes.
2Terms, definitions and abbreviated terms
For the purposes of this document, the following terms, definitions and abbreviated terms apply.
2.1 Terms and definitions
automatic tank gaugeATG
instrument that continuously measures liquid height (dip or ullage) in storage tanks
NOTE1 An automatic tank gauge usually includes a level sensor, a gauge head and associated mounting hardware,and in some cases local display.
NOTE 2 Automatic tank gauges are also known as automatic level gauges (ALGs).
automatic tank gauging systemATG system
system that includes ATGs at the cargo tanks and controldisplay unit that processes and displays output signalsfrom the ATG along with any other parameters required to determine the liquid level, i.e. liquid/vapour interfaceNOTE The ATG system can also compute the volume of LNG in tanks, using the values of cargo tank temperatureand pressure, draft, and tank capacity table.
custody transfer measurement systemCTMS
system that processes inputs from an ATG system, thermometers, pressure gauges, etc., and provides custodytransfer measurement information on board, generating documents with regard to custody transfer of LNGNOTE The ATG system can be incorporated as part of a CTMS.
ATG that uses a float to detect the liquid level
NOTE The float is guided by a tape or wire that is connected to a drum or a ratchet in the gauge head, where the levelmeasured is displayed locally and/or remotely.See Annex D for more descriptions.
hydrostatic-type ATGhydrostatic tank gaugeHTG
ATG that determines liquid level based on the differential of pressures measured by the pressure sensorsvertically installed in a cargo tank with temperature sensors
NOTESee Annex E for further descriptions.
intrinsic errorinherent error
error of an ATG when it is tested against a reference standard under controlled conditions as specified bythe manufacturer
ATG that measures the liquid level by magnetic reed switches with a float sensor including magnets, or bymagneto-strictive principle
NOTESee Annex C for further descriptions.
ATG that utilizes an antenna to transmit electromagnetic continuous waves toward the liquid in a tank, and toreceive electromagnetic waves which are reflected at the surface of the liquid
NOTESee Annex B for further descriptions.