2.1 Interface detectors may be permanently installed
or portable.
2.2 Interface detectors carried on board should
be capable of detecting the vertical position of the interface at
any level in the tank.
2.3 Interface detectors need not indicate the
interface position continuously.
2.4 If permanently installed equipment based on
stationary sensors only is provided, the information obtained about
the interface should be at least equivalent to that obtainable from
portable equipment when used in a normal operating pattern.
2.5 The position of permanently installed equipment
or the position of the access openings for portable equipment should
be selected with due regard to the internal structure of the tank
and reasonable ship movement.
2.6 The control and display unit of a permanently
installed system should be located in the cargo control room or similar
space.
2.7 Permanently installed equipment inside the
tank should be able to withstand the impact from the jets of tank
cleaning equipment.
2.8 Permanently installed and portable equipment
should be arranged and used with due regard to relevant operational
safety precautions.