Instrumentation for LNG storage tanks.

(a) Each LNG storage tank having a capacity over 70,000 gallons (265,000 liters) must be equipped with a sufficient number of sensing devices and personnel warning devices, as prescribed, which operate continuously while the tank is in operation to assure that each of the following conditions is not a potential hazard to the structural integrity or safety of the tank:

Condition Instrumentation (1) Amount of liquid in the tank Redundant liquid level gages and recorders with high level alarms, and a minimum of one independent high level alarm. (2) Vapor pressure within the tank Redundant gages and recorders with high and low pressure alarms. (3) Temperatures at representative critical points in the foundation Temperature indicating and recording devices with alarm. (4) Temperature of contained liquid at various vertical intervals Temperature recorders. (5) Abnormal temperature in tank structure Thermocouples located at representative critical points with recorders. (6) Excessive relative movement of inner container and outer shell Linear and rotational movement indicators located between inner container and outer shell with recorders.

(b) LNG storage tanks with a capacity of 70,000 gallons (265,000 liters) or less must be equipped with the following:

(1) LNG liquid trycocks, when attended during the filling operation.

(2) Pressure gages and recorders with high pressure alarm.

(3) Differential pressure liquid level gage.

(c) Each storage tank must be designed as appropriate to provide for compliance with the inspection requirements of this part.

[45 FR 9203, Feb 11., 1980, as amended by Amdt. 193-16, 63 FR 37505, July 13, 1998]