MIL-STD-810F Method 512.4 – Immersion in Water

Experience has shown that a temperature differential between the test item and the water can affect the outcome (leakage) of an immersion test. Increasing the test item temperature above the water temperature for the immersion test usually includes heating of the test item to establish a pressure differential (while cooling) to determine if the seals or gaskets leak under relatively low-pressure differential, and to induce expansion/contraction of materials. Although desired, establishing a specific temperature differential for fording tests is often impractical due to the size of the materiel.

How Trimble Tests for Immersion

The minimum requirements to pass the immersion test are heating a unit for an hour to a core temperature of 49 C (120° F). Within a minute after the removal from the heat source, the device is plunged into 22 C (72° F) degree water to a depth of 1 meter, and kept there for 30 minutes. The unit must continue working the entire time, start to finish, to pass the test.

Recon, Ranger, Nomad and Yuma all passed the test.