ISO 6425 tests

[Theory]

I’ve found a very complete link about the testing details of the ISO 6425 certification:

http://perso.orange.fr/fwi-sail/zdiver1.htm (in French).


I made a quick translation of the tests :

-Magnetic test : 3 expositions to a strong magnetic field (4.800A/m). The watch must keeps it accuracy to +-30sec/day despite the magnetic field.
-Shock resistance : several drops from a height of 1m on a horizontal hard surface (usually hard wood).
-Chemical test : the watch is immersed in salty water to test its rust resistance. The test water must have a salinity higher than normal sea/ocean water.
-Long immersion test in corrosive environment : same as above, for a long period.
-Thermal shock : the watch is successively heated and cooled. It must keep its accuracy and show no wear on the case and the movement.
-Crown resistance : the crown is mechanically grasp to simulate an accident, it must not tear away.
-Pressure test : The watch is exposed to an overpressure of 2bars. No more than 50µg/min of air must get inside the case.
-Water overpressure : L is the water resistance claimed by the manufacturer:
Delta P = (L+1/4L)/10 bar : the watch must resist a water pressure 25% above the resistance claimed by the manufacturers.
The pressure must be applied suddenly to the watch.
The test lasts two hours.
The case then passes another thermal shock. Any trace of condensation will discard the watch.
-Accuracy test : after the watch has successfully passed all the tests above, its accuracy must have been kept by +-30sec.

If the watch passes successfully every test (magnetic, shock, chemical, pressure, water and thermal) and keeps its accuracy then it’s officially certified as a Diver watch to guarantee its reliability under critical circumstance.

[tallguy]

Makes me appreciate my SAR that much more! What other watches do you guys know of with that ISO level of certification?

[cnmark]

OT: Tallguy (Steve), you beat me reposting this on MWR by 10min, and 6 on EOT...

[Dave E]

Very interesting, thanks for that!

[Theory]

Makes me appreciate my SAR that much more! What other watches do you guys know of with that ISO level of certification?

Seiko divers, Omega Seamaster, Rolex Submariner/Seadweller, Citizen and Orient divers, your Marathon SAR, and some other diver watches from serious brands.
The "diver" word is often nothing more than a marketing term, many brands have a "diver" collection that barely are water resistant, and obviously don't pass the ISO tests.
If you can read French, the document states that some companies go as far as selling "diver" watches but warn the user not to wear them under the shower..

[tallguy]

OT: Tallguy (Steve), you beat me reposting this on MWR by 10min, and 6 on EOT...

:-D :-D what do i win, what do i win?!?!?!? :gold :silver :bronze

PS even went to TZ-UK!

[Theory]

Several things I'd like to add..
First, the original document is a simple review of the ISO test. It's not the complete document.
I wanted to provide a quick and dirty translation, which is by no mean as accurate as the original ISO. It's a general sum-up and will indeed be worthless to the technical enthusiast - including me, in all honesty.
The doc left me pretty frustrated too, but I thought it would be worth sharing it nevertheless.
Sorry for those who said it's was all "next to worthless".
The official, detailed, and complete document is available at the ISO site:
http://www.iso.org/iso/en/CatalogueD...CSNUMBER=12774
but they will charge you ~50$ to read it.
If someone is willing to buy it...

There are many things that I'd like to know too. What they mean by "several", what temperatures, how fast... I guess the original author of the review wanted something easily understandable for a broad audience.
I tried to contact the author for more information, but he doesn't put his email anywhere.

[cnmark]

:-D :-D what do i win, what do i win?!?!?!? :gold :silver :bronze

PS even went to TZ-UK!

:-DThe honor of being the fastest multi-board-poster of the day!!:gold:gold:gold

Cheers,
Markus

[lysanderxiii]

To correct a few minor points:

-Magnetic test : 3 expositions to a strong magnetic field (4.800A/m). The watch must keeps it accuracy to +-30sec/day despite the magnetic field. The +-30 seconds variation is from the accuracy as measured before the test. If the watch shows a +55 sec/day rate prior to the test and a +65 sec/day rate after, it has passed the test.

-Shock resistance : several drops from a height of 1m on a horizontal hard surface (usually hard wood). Not several drops but 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/sec. The change in rate allowed is +-60 seconds. (For the watch used above with the, now, +65 sec/day rate, the maximum allowable rate is +125 sec/day)

-Chemical test : the watch is immersed in salty water to test its rust resistance. The test water must have a salinity higher than normal sea/ocean water.
30 gr/liter NaCl solution for 24 hours.

-Long immersion test in corrosive environment : same as above, for a long period. A long period being defined as 50 hours, but the water does not have to be salt water.

-Thermal shock : the watch is successively heated and cooled. It must keep its accuracy and show no wear on the case and the movement.
A soak in 40 C water for 10 minutes transitioning to 5 C within 1 minute for another 10 miniute soak at that temperature followed by transitioning back to 40 C for 10 more minutes. (40 C = 104 F and 5 C = 41 F) No water leakage allowed. No rate change specified.

-Crown resistance : the crown is mechanically grasp to simulate an accident, it must not tear away.
A bit of a misleading description of the test, the actual test is with the watch submerged and under 25% more than the rated pressure, a 5 Newton force shall be applied perpendicular to the rotational direction of the crown (and pushers, if any), and no water leakage shall occur.

-Pressure test : The watch is exposed to an overpressure of 2bars. No more than 50µg/min of air must get inside the case. This is an optional test.

-Water overpressure : L is the water resistance claimed by the manufacturer:
Delta P = (L+1/4L)/10 bar : the watch must resist a water pressure 25% above the resistance claimed by the manufacturers.
The pressure must be applied suddenly to the watch. Within one minute.
The test lasts two hours.

Subsequently the overpressure shall be reduced to 0,3 bar within 1 min and maintained at this pressure for 1 h. The watches shall then be removed from the water and dried with a rag.

The case then passes another thermal shock. Any trace of condensation will discard the watch. This is not really intended to be a thermal shock test, but a test to see if any water as entered the case. The test is that the watch be heated to a temperature of 40-45 C for about 10 minutes, then a drop of water at a temperature of 18 to 25 C shall be placed on the crystal, after 1 minute ther shall be no condensation on the inside of the crystal. This test is performed after the long immersion test and the thermal shock test to see if water has entered the case.

-Accuracy test : after the watch has successfully passed all the tests above, its accuracy must have been kept by +-30sec. There is no specified rate a diver's watch must meet. (See magnetic and shock tests)


And you forgot one of the more important tests, the strap attachment strength test. A force of 200 Newtons shall be applied to each spring-bar (or attaching point) in opposite directions with no damage to the watch of attachment point.

[Theory]

Lysanderxii, you are now my official hero

[Theory]

A few additional details :

-The bezel must be unidirectional and have a visible mark at least every 5mn. I saw nothing regarding whether they should glow or not.
-Bidirectional bezels shall be accepted if they have a lock mechanism.
-Digital displays can also be accepted if they are clearly visible (visible by human eyes 25cm from the watch, in total darkness)
-The watch must have an indicator showing it’s working properly– usually a running second hand.
-Quartz watches shall have a low battery indicator, usually an LED.

Also, shock resistance can be specified by the DIN 8308 certification.

[lysanderxiii]

According to ISO 6425, only watches that have passed these test (or, in the case of statistical samples, the lot from which the test watches have been taken,) can have the words "Diver's Watch" inscribed on the case (or a translation of "diver's watch" in the respective langauge) followed by the depth rating in meters.

The minimum depth rating shall not be less than 100 meters.

Most dive-style watches with high depth ratings are not tested to this specification, but to ISO 2281, which is a lot less stringent. This is why you see people saying that you need 200 meters ratings to dive. You do, if your watch is only tested to ISO 2281.

[lysanderxiii]

-The bezel must be unidirectional and have a visible mark at least every 5mn. I saw nothing regarding whether they should glow or not.
The following item must be visible at a distance of 25 cm in darkness:

1) Time (the minute hand shall be clearly distiguishable from the minute hand)
2) Set time of the time pre-selecting device (bezel dot is all that is necessary)
3) Indication that the watch is running (as you noted)
4) EOL on battery powered watches (the four second jump of the second hand at low battery power is acceptable, and I believe the most common)

-The watch must have an indicator showing it’s working properly– usually a running second hand. Since this must be visible in darkness, the second hand (if used as the "watch-is-running" indicator) must have a luminous tip or tail.

Also, shock resistance can be specified by the DIN 8308 certification. DIN 8308 is a reprint of ISO 1413 by the German Standards Institute. There are also versions issued by the British, Korean and Japanese standard institutions.

Others specifications referenced:

ISO 764 - Anti-magnetic watches
ISO 2859-2 and -3 concerning sampling procedures in testing.

It should also be noted that any device that is required to be operated under-water (ie buttons on a digital watch to operate the back light or start a count-down timer) so as to conform to the above noted requirements, must be tested during all the under pressure tests listed.

[Theory]

Thank you very much for sharing your knowledge.

Is there a way to know to which specifications complies a watch ?

I'd be particularly interested to compare an average casio G-shock (like a DW5600) and a Seiko Diver 200, in terms of certifications (I suspect there is a lot of marketing behind the water resistance of G-shocks).

[lysanderxiii]

Theoretically, if the watch states "diver's" on the back or dial it meets ISO 6425. I know that most of Seiko's divers have "diver's" or "dive" on the back. Also, Marathon SAR (and their kin) have something to the effect of "this watch has been tested to ISO 6425" stamped on the back.

Conversely, if the watch just has "Water-resistant XXX meters" (or YY bar), I would have to assume that it has only been tested to ISO 2281.

For comparison ISO 2281 tests:

- No shock or magnetic properties required.
- Air overpressure as in ISO 6425, but not optional
- Long exposure - in 10 cm of water for one (1) hour.
- Thermal shock - as ISO 6425 but the temperatures are only 40 C and 20 C and the times are just 5 minutes.
- 5 Newton force perpendicular to the axis of the crown and pushers/buttons under 10 cm of water.
- Water overpressure - tested at the rated depth for only ten (10) minutes.
- No negative pressure test.
- No strap attachment test
- No corrosion test.

ISO 2281 states that "water-resistant" (or a translation) followed by the pressure rating in bars of over-pressure shall be stamped on the back, if no over-pressure rating is noted, it will be tested to a 2 bar overpressure. As an alternate, a depth in meters may be substituted, with each 10 meters depth defined (for the propose of the specification) as 1 bar.

[Crusader]

Lysanderxii, you are now my official hero

Mine too. B-)

[NSG1Tausend]

Thanks Theory

Thanks lysanderxiii

It makes you think a little more, I bought my U1,Rasmus,UTS, and Stowa Prodiver because of their looks/style, reps, size, heft, class 1000M, even though I dont dive. So you hope that with those names you are getting a great watch that meets ISO specs, but now I see that there are different classes and they do not all meet those set out. I have been to that french dive info site before and found it very useful as they rate many of the popular dive watches out there.
Thanks
Robt

I’ve found a very complete link about the testing details of the ISO 6425 certification:

http://perso.orange.fr/fwi-sail/zdiver1.htm (in French).


I made a quick translation of the tests :

-Magnetic test : 3 expositions to a strong magnetic field (4.800A/m). The watch must keeps it accuracy to +-30sec/day despite the magnetic field.
-Shock resistance : several drops from a height of 1m on a horizontal hard surface (usually hard wood).
-Chemical test : the watch is immersed in salty water to test its rust resistance. The test water must have a salinity higher than normal sea/ocean water.
-Long immersion test in corrosive environment : same as above, for a long period.
-Thermal shock : the watch is successively heated and cooled. It must keep its accuracy and show no wear on the case and the movement.
-Crown resistance : the crown is mechanically grasp to simulate an accident, it must not tear away.
-Pressure test : The watch is exposed to an overpressure of 2bars. No more than 50µg/min of air must get inside the case.
-Water overpressure : L is the water resistance claimed by the manufacturer:
Delta P = (L+1/4L)/10 bar : the watch must resist a water pressure 25% above the resistance claimed by the manufacturers.
The pressure must be applied suddenly to the watch.
The test lasts two hours.
The case then passes another thermal shock. Any trace of condensation will discard the watch.
-Accuracy test : after the watch has successfully passed all the tests above, its accuracy must have been kept by +-30sec.

If the watch passes successfully every test (magnetic, shock, chemical, pressure, water and thermal) and keeps its accuracy then it’s officially certified as a Diver watch to guarantee its reliability under critical circumstance.

[Theory]

The Sinn U1 and UTS watches both are compliant (I'm in love with UTS watches, too bad my wrist is too small for them).
Your U1 is even made of a special alloy to provide some extra resistance. They are real diver watches.

I would just not go with a Casio (even a G-shock) or a Timex :-X

[lysanderxiii]

Any watch rated to 1000 meters, even if tested to "just" ISO 2281 would be more that sufficient for diving. That's beyond the crush depth of some submarines!!

For that matter, watches rated to 300 meters under ISO 2281 would probably be sufficient for sport diving, providing it met all of the visability requirements.

And, one last thought on the subject, just to needle the Rolex fans out there - Neither the Submariner nor the Sea Dewller are marked in accordance with either ISO 6425 or ISO 2281, what are they tested to? (Of course, it may be stated in the supplied instructions. I'm sure an owner of one will supply the answer.)