Underground Double Skin Steel/Polyethylene Tank

The double skin steel-polyethylene underground tanks are manufactured based on the standards EN12285-1 (interior body) and UNE 62350-3 (exterior body).
Interior body - Body and funds are executed on S235JR carbon steel plate or equivalent quality.
Exterior body - Body and funds in high density polyethylene.

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).

In terms of interior finishing, the surfaces and welds will be in its natural state, cleaned and properly dried. Outside surfaces are coated with high density polyethylene wall.

Control/Testing Conditions
Welds test exams;
Hydraulic test (interior body);
Pneumatic test (double skin chamber);
Vacuum test (double skin chamber);
Dimensional control.

Additional Options
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
  • Fax +351 249 544 691
  • Mobile (Central) +351 919 984 246
  • E-mail: geral@heh.pt