The SPF type pressure sensor was specially developed for pore pressure measurement on freezing or frozen samples. The stable oil-bearing membrane is designed so that forces caused by ice crystals do not damage the sensor and the calibration curve is maintained. This allows the sensor to be placed exactly where the pore pressures are to be measured – directly on the sample surface.
A typical application is the use as a pore pressure sensor in oedometer cells and in particular in oedometer cells for carrying out frost-heave-tests as a suction stress sensor.