All pipe systems are designed to carry fluids to a destination. When those fluids are dangerous, hazardous or corrosive, it is nearly always necessary to use dual containment to protect against loss of containment.
Dual containment pipes have an inner tube to carry the fluid and an outer pipe. The inner pipe transports the fluid, and the outer pipe protects the inner pipe, as well as acting as a method of secondary containment should the first fail.
Dual containment use cases
Double containment pipes were initially used in the 1970s. They found their first use transporting petrol and oil which they are still used for today.
The Control of Pollution (Oil Storage) (England) Regulations 2001 states that petrol, diesel, vegetable, synthetic and mineral oils must be adequately controlled. Dual containment will be necessary for these fluids in certain scenarios.
Dual containment plastic pipe systems are also used to protect against leaks of corrosive and hazardous fluids. These pipes go underground or overground and often interconnect to transport fluids in a safe and efficient way.
Fields of application include:
- Water treatment
- Metal plating
- Life sciences
- Disposal drainage
- Chemical process
- Effluent transport
Dual containment pipe system design
The inner pipe of a dual containment pipe system is called the ‘containment pipe’ because it carries and contains the fluid. The material for this pipe is carefully selected based on what fluids it will carry and at what temperature and pressure.
The outer pipe is made from a different material selected based on the conditions and environment it will be exposed to. Under and overground pipes can be made from different materials as they are exposed to different conditions.
PVC and polyurethane are the most common plastics for the outer containment tubes, while PFA is a common material for the inner tube.
For non-hazardous materials like water, a dual containment pipe may have an inner and outer pipe made from the same material, such as PVC. Underground pipes can have a steel outer pipe so that it is load and weight bearing.
The primary aim of all dual containment piping systems is to protect against loss of containment. The pipe system must be designed taking into account the fluids handled, the ecology of the local area, and health and safety legislation.
Dual containment is often a legal and regulatory requirement to transport combustible fluids, oils and chemicals in a safe way. Whenever there is a risk or danger to people and the environment, dual containment should be used.
The pipe system should be designed with consideration for the fluids it will carry and at what temperature and pressure.
Temperature and pressure both have a significant effect on plastics and are therefore determining factors in the types of material that are suitable for the fluids you handle. The system must be able to withstand the pressure exerted on it, and it must be able to function as intended within a specified temperature range.
Contact us today to find out more
These engineering requirements are something we can discuss with you in detail. Contact us today to get a specialist dual containment solution.
