MIL-Spec Tests

MIL-Spec tests are designed to push the watches to the extreme, attempting to break them.

Only the fittest survive and earn the right to "wear" the MIL-PRF-46374G marking.

Our daily lives are surrounded by all kinds of standards and specifications. There are uncountable standards administered by different countries such as ASTM (American Society for Testing and Materials), BSI (British Standards Institution), JIS (Japan Industrial Standards), KIS (Korean Industrial Standards) and many more for all the products and things we use in our daily lives.

All these standards, however countless there may be, are all laid out to ensure that the product or item concerned is able to perform and function fully and safely within the context of normal human living.

In other words, it doesn't matter if the mobile phone can't be used under water since that is not within the context of normal human living and therefore doesn't go against the industrial standards specified for that item.

This is where MIL-Spec differs.

High pressures of deep sea, excruciating heat and chilling cold of deserts, high humidity of tropical jungles, north pole, south pole.

MIL-Spec tests the item concerned for 100% functionality and ensure that it does what it's meant to do under the aforesaid environment and conditions.

That is why the materials, designs, testing methods, usability criteria specified by MIL-Spec are all very stringent at the highest levels.

That is also the reason why MIL-Spec is widely known to be the most stringent superlative standards.

Take a look at the table below which shows some sample MIL-SPec tests.

Take a watch from the commercial market and subject it to the conditions specified in the table.

Without a tinge of doubt, the watch would be severely damaged, perhaps even beyond recognition.

Some of the tests do make you wonder what purpose do they exactly serve or whether they are necessary.

And you are probably right. MIL-Spec tests are designed to push an item to its extreme limits, hoping to break it.

Only the fittest of the fittest can survive, and for those who do, they earn the right to be officially recognized as a true-blue military watch.

Test Item Test Condition Test Duration
Simple harmonic
(1) Vibration perpendicular to dial
    Amplitude of 0.762 ± 0.127 mm

(2) Vibration in plane of dial and in
     direction from 12 to 6
    Amplitude of 0.030 ± 0.005 inch

(3) Vibration in plane of dial and in
     direction from 9 to 3
    Frequencies varied uniformly
between 30 Hz to 60 Hz to 30 Hz
(1) - (3)
20 minutes each
Shock Drop from height of 50 cm, uncontrolled, onto vinyl tile 3 mm thick affixed
to concrete block
Storage (1) -45 °C ± 1.1 °C
(2) 15.5 °C to 32.2 °C
(3) 60 °C ± 1.1 °C and
≥ 50 percent relative humidity
(4) 15.5 °C to 32.2 °C
(1) - (4)
24 hours each
Water resistance (1) Complete immersion in distilled water with approximately 1 percent by weight wetting solution under one atmosphere (14.7 psi) and at room temperature

(2) Complete immersion in distilled water with approximately 1 percent by weight wetting solution under three atmospheres (44.1 psi) and at room temperature
(1) - (2)
5 minutes each
Water leakage Submerged in a measured volume of distilled or deionized water, equal to approximately 10 times the volume ofthe watch, at 23 °C ± 1 °C 24 hours
types II & III
125 ± 1 Gauss magnetic field, stem
parallel to direction of field
10 minutes
types II & III
Altitude of 10,700 meters
(35,000 feet)
60 minutes
Salt fog,
types II and III
Salt fog test Method 509.3,
48 hours
Human perspiration
types II and III
(1) Immerse watch in a saturated sodiumchloride solution containing 5 percent by volume lactic acid (65 strength) at 91 °C ± 1 °C

(2) Air dry

(3) Store in atmosphere produced by a 50 percent solution of glacial acetic acid
(1) Instantaneous

(2) 2 hours

(3) 20 hours
Readability in total
After having been stored in total darkness for 8 hours, and without any intervention on the part of the user, watch shall be readable in total darkness 8 hours

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