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How does a Diver’s Watch become ISO certified?

Question:

How does a Diver’s Watch become ISO certified?

Asked by James from Ohio.

Answer:

The ISO 6425 standard is only awarded to the most robust and reliable diving watches on the market.

As well as depth rating (which must be at least 150 meters to comply with this standard), the watch has to meet many other standards such as the following:

  • The presence of a unidirectional bezel with at least at every 5 minutes elapsed minute markings and a pre-select marker to mark a specific minute marking.
  • The presence of clearly distinguishable minute markings on the watch face.
  • Adequate readability/visibility at 25 cm (9.8 in) in total darkness.
  • The presence of an indication that the watch is running in total darkness. This is usually indicated by a running second hand with a luminous tip or tail.
  • Magnetic resistance. This is tested by 3 expositions to a direct current magnetic field of 4,800 A/m. The watch must keep its accuracy to ± 30 seconds/day as measured before the test despite the magnetic field.
  • Shock resistance. This is tested by two shocks (one on the 9 o’clock side, and one to the crystal and perpendicular to the face). The shock is usually delivered by a hard plastic hammer mounted as a pendulum, so as to deliver a measured amount of energy, specifically, a 3 kg hammer with an impact velocity of 4.43 m/s. The change in rate allowed is ± 60 seconds/day.
  • Chemical resistance. This is tested by immersion in a 30 g/l NaCl solution for 24 hours to test its rust resistance. This test water solution has a salinity comparable to normal seawater.
  • Strap/band solidity. This is tested by applying a force of 200 N (45 lbf) to each spring bar (or attaching point) in opposite directions with no damage to the watch or attachment point.
  • The presence of an End Of Life (EOL) indicator on battery powered watches.

(Source – Wikipedia)

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