Nowadays, liquid petroleum gas is stored and transported in LPG composite cylinders. These cylinders are widely used as alternatives to steel cylinders. LPG is made up of flammable gases such as propane, butane, and a combination of propane and butane. LPG composite cylinders eliminate any flammability concerns since they are non-explosive, safer, and lighter than bulky steel cylinders. Moreover, they are transparent, so you can see the amount of LPG inside.
Types of cylinders
The standard defines four types of LPG cylinders. Most interesting nowadays is type IV. Type IV cylinders LPG cylinders are equipped with gas-tight liners (usually HDPE liners) reinforced with a composite wrap around the entire tank (fully wrapped).
The composite reinforcement gives the cylinder strength. LPG composite cylinders are used in different applications, including domestic use, caravans & mobile homes, camping, resorts, hotels, industrial, fork-lift trucks, gas cutting, boats, and many more other uses.
Compound LPG cylinders are available in different sizes ranging from 5kg to 17kg. A cylinder can be used for a variety of purposes according to its size.
Composite LPG cylinder manufacturing process in 4 simple steps

- This inner layer is formed as roto-molded or blow-molded high-density polyethylene (HDPE) liners, which serve as seamless gas barriers.
- The cylinder is mounted with a brass insert typically welded to an injection-molded HDPE boss or embedded during the molding process
- Reinforcement occurs with winding glass fibers impregnated with epoxy resin. This layer provides an extremely high strength-to-weight ratio and withstands the pressure of LPG.
- Adding an outer HDPE casing will enhance the strength even further. Besides providing protection, this provides an ergonomic grip as well and is designed for stackability for effective storage during transportation.
The burst pressure is the maximum amount of pressure as a safety factor that a cylinder can withstand. The burst pressure is defined as 2.4 times the test pressure.
Contrary to steel cylinders, composite cylinders can not explode. They consist of a non-metallic gas-tight liner with a fiberglass-bound composite layer that can be burned in a fire without any concern for an explosion. After a few minutes of engulfing the fire, the outer casing starts to melt and the LPG oozes out through the cylinder wall from a different location and reducing the internal pressure and instigating localized burning only. This makes a safer option for all end-users and any industry, especially gas companies. You can see the result of the burst pressure test in the photo.

Benefits compared to steel cylinders
In addition to being heavier, conventional steel cylinders can corrode easily and don’t show the gas level, and are not safe from fire-related explosions. LPG composite cylinders, on the other hand, are lightweight, rustproof, non-explosive, and translucent.
The most widely used source of energy for cooking is LPG. As a result of composite LPG cylinders’ reduced weight, they are easier to handle and reduce transportation costs. Steel LPG cylinders that can hold the same amount of LPG are approximate twice the weight of composite LPG cylinders.
According to our customer’s demands, government initiatives in India, Indonesia, China, and Africa are promoting LPG use as a clean cooking fuel as well as a transportation fuel. This is due to the global push to cut carbon emissions.