“ Ullage “ Normally The Industry Expected Amount Is 3 - 5 %

Actual safe fill level of the tank - explained… fuel tanks require a gap of air referred to as “ ullage “ to allow for expansion and breathing in the tank.
Normally the industry expected amount is 3 - 5 %
So if you have a tank with a capacity of 1000 litres and you want to put 1000 litres into it - it needs to have a brim full capacity of 1050 litres.
This of course has variations to this depending upon the shape and size of the tank.

Also if the tank is a self bunded type it has other considerations to form part of its design.

• No pipe can protrude into the wall of the tank below the safe fill level as per AS 1940 - 2017 so this may reduce the SFL of the tank considerably to comply with this requirement.
• The fitting of an overfill valve can effect the SFL as many valves require certain space inside the tank to operate - hence reduces the shut off capacity they can operate it which means the tank level will be less when full.

So we recommend to ask your tank supplier what is the true safe fill level of the tank you are offering me?

As what you may require and what you have been quoted could be ways apart.
We have noticed some designs give a tank capacity and that actual SFL - legal allowed capacity is actually 10% less which means you are getting a smaller tank.
At Equipco - we only ever quote the true Safe Fill Level so you know exactly what tank size you will receive and that it is fully compliant with all relevant Australian Standards.
We hope you find this explanation beneficial and keep it for future reference when doing your own tank analysis comparisons.