There is no special advantage of painting cylinder bottles either in red or the blue colour. LPG gas cylinder bottles can be painted in desire colours. The manufacturers gurantee that the production of these cylinder bottles comply with the regulations in force in the regulator country of use. Foreign cylinder bottle manufacturers should do proper checking of any specific directives covering its application. They are governed by rules of the country who may mandate that domestic or commercial LPG cylinder bottles should be painted in red or blue colour for the sake of identify. However, most of the rules of coloring or painting may not apply to camping gas cylinder bottles. In the UK, only commercial cylinder bottles are painted in red or blue colour.
In the UK, they do have strict regulations concerning LPG used for various purpose. Some country standard LPG for cooking gas is Propane, while other country allowed only Butane or the mixture of both Propane and Butane. In Africa, the most used type of LPG is the Propane and Butane mixture, which may be why most government agency see no reason to mandate colours as means of identification.
In the UK, colours are used to differentiate the type of LPG presently contained in a particular gas cylinder bottle. The two most popular exchange-only bottle vendors in the UK: Flogas and Calor-gas, identify Propane and Butane with red or blue colour. It helps to identify the LPG delivered to customers. Also, painting gas cylinder bottles helps people to know which LPG is being offered for refilling at various gas stations.