Double Wall System (RDP)

Double Wall System (RDP)

Application in situ. So no need for projects, permits, or building works.

The procedure developed consists of manufacturing a double-wall tank inside an old tank, with a permanent leak detection solution, transforming a single-wall tank into a double-wall one.

This tank is designed to prevent leaks and, therefore, subsoil contamination thanks to its monitored interstitial chamber among other components.

A leak detection system is installed which informs and emits a visible and/or audible signal in the event of entry/leak of fluid in the interstitial chamber, constituting a permanent control and protection system of the tank.

It can be installed in any type of new/old, underground/above-ground tank whether it is made of fibre or steel, thanks to our environmentally friendly resin and tissues that stick to any surface.

The 3 main qualities that a lining should have are:

  1. The adherence (grip) of the material to the tank.
  2. It is chemical resistance (the petrol doesn’t attack it)
  3. Its mechanical resistance manages to remove any cracks, pores, or bubbles in the tank and reinforces the structural strength of the tank.


  • Single-walled tanks are transformed into double-walled tanks on site. There is no need for projects, permits, building works, or stoppage times resulting in lost profits.
  • The double wall along with the installation of a permanent leak detector obtains a true system of permanent detection.
  • The system prevents subsoil contamination or contamination of hydrocarbons stored in the case of any leak or defect on both walls, interior or exterior.
  • If the exterior wall of the tank punctures, there would be a containment lining before reaching the interstitial chamber.
  • The interstitial chamber created is formed between the two walls of GRP, preserving the passive interior protection of the metal of the exterior wall of the old tank.
  • The First wall, Interstitial chamber, and Second wall all form a monolithic single-bodied system since all of the material is identical, resins and fiberglass complying with standard UNE 53991 in terms of adherence.
  • Since it is monolithic, there are no forces or stresses that may cause the shedding between layers and between the first wall and the second.

Installation of the permanent and automatic leak detection system on the detection chamber

Once the double containment system is built, the permanent leak detection system will be built on the detection chamber, authorized and approved in accordance with the European standard EN-UNE 13160 according to the construction type which could be:

  • By vacuum or pressure.
  • By liquid. The liquid in the detection chamber will be in accordance with the standard UNE 62350 – 4: 1999 of a type that is non-toxic. An anti-freeze is recommended (as a minimum of up to –20 ºC). It will have antibacterial additives and will be biodegradable and colored to make the refilling of the interstitial chamber visible.

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