LPG worth (LW) is the amount of LPG gas that can be contained in a gas bottle. LPG Worth helps us to know the level of LPG gas that should be refill, so as to prevent overfilling. You can see the LPG Worth (LW) stamped on every gas cylinder bottles neck ring you see.
For a 50kg propane gas bottle, with details as follows:
Tara Worth (empty weight) => 50kg
Net Weight => 47kg
Scale Reading => 50kg (along with the gas bottle dimensions)
LPG Worth => 45kg
Water Capacity => 100.2 Litres
So, to get the LPG Worth, to know approximately how much of gas reminant in the 50kg tank - Tare Worth is substracted from scale Reading.
50kg - ??? (let's assume the scale reading as 60kg).
LPG Worth will be 50kg (empty weight) - 60kg (scale reading) => 10kg (gas reminant).
To refill the 50kg together with the 10kg gas reminant at the refilling site:
50kg (empty weight) - 10kg (gas reminant) => 40kg (LPG Worth)