ISO 6425 Watchmaking - Diving Watches

The “ISO 6425 Watchmaking - Diving watches” standard, developed by the International Organization for Standardization (ISO), describes the requirements and test methods for diver watches and watches used in deep diving (watches used for mixed gas diving are included in the standard annex (Annex A).

This standard applies to diving watches designed to withstand diving to a depth of at least 100 m and equipped with a safe measuring system that shows the dive time visible in the dark. It also shows the mark that the manufacturer is authorized to apply them.

For the purposes of this standard,

• SCUBA diving is a mode of underwater diving in which the diver uses a self-contained underwater breathing apparatus (SCUBA) to breathe underwater.
• Saturation diving is a diving technique that allows divers to reduce the risk of decompression sickness (the bends) when working deep dives for long periods of time. In saturation diving, divers live in a pressurized environment corresponding to the depth of the dive, this may be a hyperbaric chamber. This can last up to several weeks, and divers decompress to surface pressure only once at the end of their mission. By limiting the number of decompressions in this way, the risk of decompression sickness is significantly reduced.
• A diver's watch is a watch designed to withstand SCUBA diving.
• A diver's watch for saturation diving is a diver's watch designed to withstand saturation diving.
• Dive duration refers to the time elapsed since immersion.
• A dive time indicator is a device used to measure dive time.

The requirements in this standard are specified as follows:

• Temperature: Unless otherwise stated, tests in water or air are performed at a temperature of 23 degrees plus/minus 5 degrees.
• Visual inspection: Visual inspection should be done without magnifying glass.
• Tested product configuration: Unless otherwise stated, tests are performed on the watch head only. If, for technical reasons or if the bracelet cannot be removed from the watch head, tests are performed on the entire watch.
• Practical significance: All the operations described are designed to simulate the conditions under which the watches will remain undamaged and still work after diving:
  • L m water (L/1 bar10) for 1 hour per dive, then
  • 1 m of water (3 bar) for 0,3 hour per dive
• 1 L is the depth of the dive in meters guaranteed by the manufacturer.
• Unless otherwise stated, all functional parts are manipulated at atmospheric pressure.
• Unless otherwise stated, all mobile systems must be in rest positions.
• Dive time indicator: The watch must be equipped with a dive time indicator (e.g. rotating bezel, digital display or other). Such a device must be protected against accidental use. This device must allow the dive time to be read with a resolution of 60 minute or better for at least 1 minutes. For analogue indicators, markings showing every 5 minutes must be clearly marked.
• The following tests are used for type testing (homologation). They must be carried out in the following chronological order. Each test sample must pass each test:
  • Visibility
  • Magnetic resistance properties
  • temperature cycle
  • Salt spray test (with bracelet)
  • Impact resistance specifications (on watch head)
  • Water resistance
  • Impact resistance properties (free fall)
  • Resistance of attachments
• 100% single watch test: During the production process, every watch must be subjected to water overpressure test resistance according to this standard.
• The dive time indicator must be readable in light with a minimum illumination of 50 lx.
• Light exposure should be carried out in accordance with standard ISO 17514. After at least 180 minutes of exposure, the visibility and readability of the following items should be checked in the dark at a distance of 25 cm:
  • Time (minute display must be clearly distinguishable from hour display)
  • Dive time readable with uncertainty of plus/minus 2,5 minutes or less
  • For analog displays, markings showing every 5 minutes
  • Indicator showing that the clock is working
  • Battery-powered watch with end of battery life indicator
• In terms of magnetic resistance properties, the watch must be tested in accordance with the ISO 764 standard and must comply with the requirements of this standard.
• Temperature cycling can be performed as an optional preliminary test on the watch, as described in the standard annex (Annex B). The condensation test should be performed prior to this test to ensure that the result correlates with this current test. All devices secured for water resistance should be locked (screwed crown and pushers, etc.).
• The watch under test should be subjected to the following temperature cycles:
  • The watch is held in the air at minus 20 plus/minus 3 degrees for 60 plus/minus 3 minutes.
  • The watch is kept at room temperature for 30 plus/minus 3 minutes.
  • The watch is held in the air at 60 degrees plus/minus 3 degrees for 60 plus/minus 3 minutes.
  • The watch is immersed in water at 5 degrees plus/minus 2 degrees for 2 plus/minus 60 minutes within 3 minutes.

Among the numerous testing, measurement, analysis and evaluation studies that our organization has carried out for businesses in various sectors, it also provides testing services defined in the “ISO 6425 Watchmaking - Diving watches” standard with its trained and expert staff and advanced technological equipment.