Ullage Reference Point
Definition - What does Ullage Reference Point mean?
Ullage Reference Point, also known as dipping reference point is a position on ullage hatches on top of a storage tank or container from where ullage measurements are taken. This is the area where all gauging and measurement activities are carried out, usually inside large storage tanks on terminals and on oil vessels (oil tankers).
Petropedia explains Ullage Reference Point
Ullage reference points are clearly marked on the ullage hatch directly above the dipping datum point and they indicate the tape position during dipping. These reference points are situated either at fixed or known distances on a ullage hatch which is greater than the maximum depth of the liquid in the storage tank. These reference points are widely used in industrial and marine settings so as to describe any empty space in a large tank or hold that is used to transport or store liquids.