ISO 19636:2019 pdf download – Ships and marine technology – General requirements for inclinometers used for the determination of trim and list of LNG carriers
1 Scope
This document provides general requirements for the accuracy, installation, calibration and verification of trim and list inclinometers used for the determination of trim and list of LNG carriers for the purpose of measuring on-board cargo level.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 60079-0, Explosive atmospheres —Part 0: Equipment — General requirements
3 Terms and definitions
For the purpose of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1 custody transfer measurement system
CTMS
system that processes inputs from an ATG (automatic tank gauge) system, thermometers, pressure gauges, etc., and provides custody transfer measurement information on board, generating documents with regard to custody transfer of LNG
Note 1 to entry: CTMS components include:
a) automatic level gauge system (radar, microwave, capacitance and float types),
b) automatic temperature gauge,
c) automatic pressure gauge,
d) trim and list indication system
Note 2 to entry: A trim and List inclinometer system can be typically incorporated as part of a CTMS.
Note 3 to entry: See Figure 1.
3.2 trim and list inclinometer
inclinometer used to determine the trim and list of LNG carriers
3.3 inherent error
error of a trim and list inclinometer when it is tested and verified against a reference standard under controlled conditions as specified by the manufacturer
4 Safety precautions
4.1 Existing safety regulations, standards and classification societies rules
It is the responsibility of the user of this document to consider the applicable safety or operating practices recommended by regulatory agencies and organizations, to establish appropriate health and safety practices and to determine the applicability of regulatory limitations prior to use.
4.2 Equipment precautions
All electric components for the ship’s trim and list inclinometer installed in hazardous areas shall meet the requirements of IEC 60079-0 applicable for the specific zone within the hazardous area. They shall conform to the applicable sections of the national and/or international electrical safety standards
5.3 Communication methods
5.3.1 Analogue current interface type
A trim and list inclinometer shall transmit its output signal as from 4 mA to 20 mA current.
5.3.2 Digital interface type
A trim and list inclinometer is to transmit its output signal as digital protocol as field bus or serial line.
5.4 Levelling of a trim and list inclinometer
It is necessary to be able to make a final adjustment of the levelling for the trim and list inclinometer once it has been installed.
This is typically achieved by placing the sensor on a plate which can be adjusted by screws until it reaches a horizontal position in both axes for the trim and list. See Figure 2.