MIL-STD-810F Method 512.4
Immersion in Water

Temperature differential between the test item and the water can influence 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 the hardware. Although desired, establishing a specific temperature differential for fording tests is often impractical due to the size of the hardware.

How Trimble Tests for Immersion

The minimum requirements to pass the immersion test are heating a unit for one hour to a core temperature of 120 °F (49 °C). Within one minute after the removal from the heat source, the device is plunged into 72 °F (22 °C) water to a depth of 1 meter, and kept there for 30 minutes. The unit must function properly at completion of test to pass.

Trimble Nomad®, Ranger™, Recon® and Yuma® all passed this test as well as the more stringent IEC-529 requirements to attain the IP67 rating.