Iranian Classification Society Rules

3. In case of relief to cargo tanks, the effect of routing high pressure LNG/NG to the cargo tank is to be documented.

207. Vent system

Special consideration is be given with respect to release rate and the potential for liquid flow through the vent mast. In general, knock-out drum with a high level alarm device is considered to be installed between relief valve and vent mast. As an alternative, a calculation showing sufficient capacity of the vent mast to avoid any liquid release through the mast is to be carried out.

208. Alarm and safety system

Alarm and safety system to be provided in accordance with Table 12.1.

Table 12.1 Monitoring of regasification system

Parameter (H=High L=Low HH=HighHigh LL=LowLow O=Abnormal condition)		Alarm	Shut down	Remark
Suction drum Pressure	H/L	●
Suction drum level	L LL	●	●
Vaporizer, heating medium inlet temperature	L LL	●	●
Vaporizer, heating medium inlet pressure	L LL	●	●
Vaporizer, heating medium outlet temperature	L LL	●	●
Vaporizer, liquefied gas inlet pressure	H/L
Vaporizer, liquefied gas outlet temperature	L LL	●	●
Vaporizer, vaporized gas outlet pressure	H/L	●
Heat exchanger, Steam supply pressure	L	●		Steam is not a direct heating me- dium
Heat exchanger, Condensate return temperature	H/L	●		Steam is not a direct heating me- dium
Overflow of the glycol heater/ Expansion tank	H HH	●	●	If a glycol heating circuit is ar- ranged
Liquid collector	H/L	●		If propane heating circuit is ar- ranged
Gas flowmeter of export system	O	●
Loss of power supply to control and monitoring system	O	●	●
Instrument air, pressure	L LL	●	●
Natural Gas to export, pressure	H/L LL	●	●
Natural Gas to export, temperature	L LL	●	●
Damages on pipe lines for export	O	●
Activation of unit’s ESD system	O		●
Gas leak detection of regasification system	O	●
Fire detection in regasification areas	O	●	●	Activation of ESD and blow down system

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