Watch Water Resistances Explained
It's easy to read the water resistance rating off your watch and think you can swim that deep with it, or swim with it at all. The truth is the water resistance you read on your watch is not what you think it means. I'll explain everything you need to know on what the water rating on your watch means and what you can do with various water ratings in only a few minutes. ******************************************* Official ISO 6425 List of Standards: https://www.iso.org/standard/66517.html (Full PDF available for purchase) ******************************************* Brief summary below (https://en.wikipedia.org/wiki/Diving_watch#ISO_6425_standard_for_diving_watches): ISO 6425 standard for diving watches Besides water resistance standards to a minimum of 100 m depth rating ISO 6425 also provides minimum requirements for mechanical diver's watches such as: Equipped with a diving time indicator (e.g. rotating bezel, digital display, or other). This device shall allow the reading of the diving time with a resolution of 1 min or better over at least 60 min. 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 exposures 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. Testing diving watches for ISO 6425 compliance is voluntary and involves costs, so not every manufacturer present their watches for certification according to this standard.
It's easy to read the water resistance rating off your watch and think you can swim that deep with it, or swim with it at all. The truth is the water resistance you read on your watch is not what you think it means. I'll explain everything you need to know on what the water rating on your watch means and what you can do with various water ratings in only a few minutes. ******************************************* Official ISO 6425 List of Standards: https://www.iso.org/standard/66517.html (Full PDF available for purchase) ******************************************* Brief summary below (https://en.wikipedia.org/wiki/Diving_watch#ISO_6425_standard_for_diving_watches): ISO 6425 standard for diving watches Besides water resistance standards to a minimum of 100 m depth rating ISO 6425 also provides minimum requirements for mechanical diver's watches such as: Equipped with a diving time indicator (e.g. rotating bezel, digital display, or other). This device shall allow the reading of the diving time with a resolution of 1 min or better over at least 60 min. 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 exposures 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. Testing diving watches for ISO 6425 compliance is voluntary and involves costs, so not every manufacturer present their watches for certification according to this standard.