ISO 13689 pdf download

ISO 13689 pdf download.Refrigerated light hydrocarbon fluids — Measurement of liquid levels in tanks containing liquefied gases — Microwave-type level gauge 1 Scope This International Standard specifies the essential requirements and verification procedures for microwave-type level gauges to be used for ship and shore tanks containing refrigerated light hydrocarbon fluids. 2 Normative reference The following normative document contains provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the normative document indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. IEC 60079-1 0:1 995, Electrical apparatus for explosive gas atmospheres — Part10: Classification of hazardous areas. 1 ) 3 Terms and definitions For the purposes of this International Standard, the following terms and definitions apply. 3.1 antenna generic term for equipment that radiates into, and receives from, the tank vapour space, electromagnetic energy in the microwave frequency band 3.2 datum level reference level, equal to the zero level in the tank calibration table, from which liquid level L is calculated 3.3 dead zone zone above the minimum measurable ullage 3.4 deflection plate metal plate set obliquely near the tank bottom to avoid influence of microwave reflection from the bottom or any obstacles NOTE A deflection plate may also be used to reduce unwanted reflections from the tank structure or fittings 3.5 hazardous area space where gas or vapour may form a flammable mixture, as described in IEC 60079-1 0 NOTE This is similar to gas-dangerous space on board the ships as described in the IMO IGC Code (1 993). 3.6 upper reference point basic point for measurement of ullage, set on the level-gauge centre-line near the gauge flange NOTE The height of the upper reference point is the distance between the datum level and the upper reference point (H in Figure 1 ). 3.7 L liquid level distance between the liquid surface in a tank and the datum level NOTE See Figure 1 . 3.8 microwave generic form for electromagnetic radiation, with wave length lying in the range 3 mm to 300 mm (equivalent to a frequency of 1 00 GHz...