Every gas cylinder bottle comes in different shapes, sizes and different materials used to manufactured them. Only a digital scale can determine the exert size of a cylinder bottle. Even s cylinder bottle with 47Kg boldly written on it, can give a 50kg when weigh on a scale. Some cylinder bottles manufactured today, WILL have every TECHNICAL information stamped on the ring neck. However, while some Doesn't, others don't. So, how can you then accurately determine the size of a cylinder bottle as such?
Substandard cylinder bottles gives wrong figures, these figures you see stamped on the neck ring are mostly wrong. Wrong Tare Weight (TW), Wrong LPG Worth (LW), and so on. Which is why it is recommended you obtain SON approved gas cylinder bottles, with ISI/BIS mark from authorized distributors only. Substandard gas cylinder bottles gives wrong Tare Weight (TW) figure. Tare Weight is the empty weight of a gas cylinder bottle, including the cylinder dimensions, also greatly affected by the material used for manufacturing. Substandard gas cylinders, sometimes do not give the LPG worth figure. You will have to figure that out yourself.
Every gas cylinder bottle, along with the gas bottle dimensions, which includes the top ring (neck), and the bottom line. However, the middle is actually the real deal. This is actually the container, also known as the LPG worth dimension. If you remove the neck and bottom ring dimensions, what you get is the LPG worth dimension. Just take a look at this 5kg cylinder.
Gas cylinder bottles or containers ate manufactured in different shapes and sizes. However, the factor that mainly determine the Tare (empty) Weight is the material used in manufacturing them. For example, older cylinder bottles tend to be heavier than more recent versions. So, lets say you ordered for the narrow and wide 3kg small size cylinder bottle, you don't expect it to weigh the same as the new version of the 3kg.
In Nigeria, the most popular home-use gas cylinder bottle/container comes in 3kg, 5kg, 6kg and 12.5kg sizes. But note, these are just general names. If you weigh a 6kg Gas cylinder bottle using a digital scale, you will get the Tare (empty) Weight, which means the total weight (plus the gas cylinder dimensions). A 6kg cylinder bottle (known as the general name), only meant that it will only contain a 6kg worth of LPG gas. These general names doesn't imply the sizes, but actually the LPG worth.