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Fast, reliable and non-destructive measurement of the permeability of concrete structures

The permeability of concrete at the surface (concrete cover) has been recognized as a major factor determining the durability of concrete structures. Many specialists emphasize the importance of this property and the possibility of measuring it reliably - not only in the laboratory but also at the building site or at components.

Permeability Measurement

The particular features of the TORRENT method are a two-chamber vacuum cell and a pressure regulator, which ensure that an air flow at right angles to the surface is directed towards the inner chamber. This permits the calculation of the permeability coefficient kT on the basis of a simple theoretical model.

The unit has a user-friendly menu technique and measures the pressure increase as a function of time according to a specific sequence. The associated data is automatically collected by the display unit and the permeability coefficient kT and the depth of penetration L of the vacuum are calculated. The measurement takes 2-12 minutes, depending on the permeability of the concrete. In the case of dry concrete, the quality class of the concrete cover can be read from a table using the kT value. In the case of moist concrete, kT is combined with the electrical concrete resistance p (rho) and the quality class is determined from a nomogram.

The TORRENT permeability tester is based on investigations which were carried out by the research center of “Holderbank Management and Consulting Ltd.”, Switzerland. The results of these measurements, which were made in the laboratory and on the building site, are in good agreement with laboratory methods, such as oxygen permeability, capillary suction, chloride penetration, etc.

Basic Equipment

  • Display unit with nonvolatile 1 MB memory for up to 200 measured objects
  • Display on 128 x 128 graphic LCD.
  • Interface RS 232 C
  • Intergrated software for printing out measured objects and transmission to PC
  • Operation with batteries for 60 h or commercial 9 VDC/0.2 A power unit
  • Temperature range -10 to +60 degrees Celsius
  • Carrying case 320/285/105 mm, total weight 2.1 kg
  • Control unit with membrane pressure regulator and pressure sensor. Vacuum connection: small flange 16 KF
  • Carrying case 520/370/125 mm, total weight 6.3 kg.

Note: The unit is operated with a commercial vacuum pump. (Not Included) Technical data according to DIN 28400: Suction capacity 1.5 m3/h, final total pressure 10 mbar, suction side connection: small flange 10 KF/16 KF, high water vapor toleration.


Active probe for determination of the concrete resistance p according to Wenner. The measured values are stored in the display unit for the respective object.