9.1.4 Installation in Extreme Thermal and Marine Environments

Freezing or High Temperature Conditions

Levelogger installation at submerged depths that may be at risk of freezing during the monitoring session is not recommended without taking adequate precautions to avoid transducer damage. When water freezes it expands approximately 9% by volume. 9% expansion can equate to extreme pressure as demonstrated in Example 9.1. Therefore, solid freezing has the potential to damage the pressure transducer, which is rated to withstand up to 150% of its depth fluctuation range. Pressures beyond this threshold may damage the transducer. With certain precautions, the Levelogger can be used in freezing liquid environments. If monitoring shallow water bodies or groundwater zones susceptible to freezing, the easiest way to avoid transducer damage is to lower the transducer to a point in the water column below the frost line or ice formation depth. In water bodies such as shallow streams, wetlands or ponds where freezing may penetrate to the bottom, install the Levelogger in a vented stilling well imbedded into the bottom of the water body beyond the frost line. In cases where the above noted precautions cannot be taken and the Levelogger must be installed in the freezing zone, it is recommended that the logger be placed inside two elongated silicon, rubber or latex balloons, the balloons be filled with a non-toxic, non-corrosive anti-freeze solution and sealed (Figure 9-9). Place the balloons in a section of perforated, 1.25” (30 mm) ID pipe and install the logger in the monitored water. The antifreeze solution will protect the Levelogger from ice expansion at the pressure transducer, yet transmit any pressure fluctuations that occur. Please note that a similar installation protection can be used when the Levelogger is monitoring liquids which are incompatible with its wetted materials. The operating temperature range for Leveloggers is -20° - 80°C (-4° - 180°F). At the opposite end of the thermal scale, exposing the Levelogger to temperatures beyond 80°C may damage the thermistor and otherwise affect the Levelogger.