Definition - What does Ullage Hatch mean?
Ullage Hatch is a small hinged opening at the top of storage tanks in oil terminals and oil tankers. The hinge is helpful in allowing tanker operators to inspect and measure the level of petroleum and stored liquid in the tanks. It also acts as a strong and secure method of providing ullage operations in gauging the volume of petroleum liquid in a storage tank.
Petropedia explains Ullage Hatch
Ullage hatches can be attached on the top of on all types of storage tanks in terminals as well as on top of containers on oil transporting vessels. Ullage hatches on compartments provide easy single bolt operation for inspection of petroleum and stored liquid. The sizes of ullage hatches range from 8 to 10 inches clear openings with various coaming heights and hardware options to meet specific requirements. The material used to the manufacture the hatch cover is high strength cast steel and the coaming is made from high quality ASTM A36 steel.