As more composite pipes are coming into use, there has been an upsurge in research related to the mechanics of composite pipes and predicting failure under different loading conditions.
Composite pipe offers several advantages over metallic systems, especially where control and mitigation regimes are not correctly followed. Metallic structures tend to require more inspection, repair and maintenance during their service life, meaning a need to schedule shutdowns while increasing expenditure. These shutdowns are mitigated against with composite pipe as it removes any problems related to corrosion as well as the need for corrosion inhibitors or cathodic protection.
With a lack of scaling and other bore restriction issues in composite pipes, they also have a superior internal fluid flow performance when compared to metallic pipes. Composite pipes also demonstrate superb strength and stiffness with much less weight, making it easier to handle without lifting equipment, thereby reducing lifecycle, transportation and installation costs.
However, composite materials can be more expensive than their metal counterparts, although this cost can be offset by the reduced assembly costs for composites.
There is a range of applications for composite pipe, including within the oil and gas industry, where they can replace expensive corrosion-resistant metals like titanium or duplex stainless steel pipe.
Composite pipe is used for transporting water for firefighting or cooling systems, drainage and sewage systems, and transporting drinking water. Composite tubes wound with filament are also used in sectors including aerospace, automotive, marine, construction and even sport.
Like other composite pipes, a flexible composite pipe (FCP) is made up of several layers, usually including at least one thermoplastic liner, reinforcing middle layers and an outer thermoplastic protective jacket. Due to its flexibility, an FCP can be spooled onto a reel for efficient transportation and fast installation without the need for as many connections.
FCPs come in a range of different types, including reinforced thermoplastic pipes (RTPs) and thermoplastic composite pipes (TCPs). However, FCPs are usually more expensive than the metallic alternatives and can suffer in terms of diameter, temperature, and pressures, depending on pipe wall thickness and the materials used. These costs can be offset by lower transport, installation, operation and maintenance costs later.
As mentioned above, TCP (thermoplastic composite pipes) systems use thermoplastic materials to provide strength and stiffness to the pipe. These pipes are fully-bonded and spoolable, usually with a polymeric inner lining, a fibre-reinforced polymeric laminate and an outer jacket for protection. This outer jacket layer can be coated to provide additional properties, such as UV resistance, depending on the application.
Composite pipes are already showing a track record of use for a range of applications across different industries. Already widely used for transporting different types of water, these pipes are seeing increasing use in the oil and gas industry where their strength, light weight and lack of problems with corrosion are proving beneficial.
Easy to transport and install, and with very little requirement for maintenance and inspection, the benefits of composite pipes balance out the increased cost of materials. Available in a range of different material types and as spoolable, flexible options the use of composite pipes looks set to continue rising.