Underground Double Skin Steel/Steel Tank

The double skin steel-steel underground tanks are manufactured based on the standards EN12285-1. The body and funds are executed on S235JR carbon steel plate or equivalent quality.

Welds shall be performed on submerged arc welding (SAW) machine, where the practice is possible. In places of difficult accessibility, the welds are performed with semi-automatic (MIG/MAG).

Regarding finishing, the interior surfaces and welds will be in its natural state, cleaned and properly dried. Outside surfaces are pickled for steel shot at SA 2.5 (EN ISO8501-1) grade. Coating with a layer of highly corrosion-resistant polyurethane which guarantees resistance to dielectric testing.

Control/Testing Conditions
Welds test exams;
Hydraulic test (interior body);
Pneumatic/hydraulic test (double skin chamber);
Dimensional control;
Ink thickness control;
Outer coating dielectric test.

Additional Options
Other manhole diameters;
Covers with special connections;
Additional man entries;
Interior painting.

About Us

The company Henriques & Henriques, S.A. exists since 1980, belongs to Henriques Group SGPS, specializing in the manufacture and sales of metal tanks, intended for the storage of liquid fuels, LPG and compressed air, as well as hydropneumatic tanks and water treatment filters.


  • Phone +351 249 540 990
  • (Chamada para a rede fixa nacional)
  • Fax +351 249 544 691
  • Mobile (Central) +351 919 984 246
  • (Chamada para a rede móvel nacional)
  • E-mail: geral@heh.pt