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Discussion Starter · #1 · (Edited)
ISO 6425Water Resistant standards for Divers Watches:

The standards and features for "Diving Watches" are regulated by the ISO 6425 - Divers watches international standard. ISO 6425 defines such watches as: A watch designed to withstand diving in water at depths of at least 100 m and possessing a system to control the time.

Diving watches are tested in static or still water under 125% of the rated (water)pressure, thus a watch with a 200 meter rating will be water resistant if it is stationary and under 250 meters of static water. The testing of the water resistance is fundamentally different from non-dive watches, because every watch has to be fully tested.

ISO 6425 water resistance testing of a diver's watch consists of:
*Reliability under water. The watches under test shall be immersed in water to a depth of 30 cm ± 2 cm for 50 hours at 18 °C to 25 °C and all the mechanisms shall still function correctly. The condensation test shall be carried out before and after this test to ensure that the result is related to the above test.
*Condensation test. The watch shall be placed on a heated plate at a temperature between 40 °C and 45 °C until the watch has reached the temperature of the heated plate (in practice, a heating time of 10 minutes to 20 minutes, depending on the type of watch, will be sufficient). A drop of water, at a temperature of 18 °C to 25 °C shall be placed on the glass of the watch. After about 1 minute, the glass shall be wiped with a dry rag. Any watch which has condensation on the interior surface of the glass shall be eliminated.
*Resistance of crowns and other setting devices to an external force. The watches under test shall be subjected to an overpressure in water of 125% of the rated pressure/10 bar for 10 minutes and to an external force of 5 N perpendicular to the crown and pusher buttons (if any). The condensation test shall be carried out before and after this test to ensure that the result is related to the above test.
*Water-tightness and resistance at a water overpressure. The watches under test shall be immersed in water contained in a suitable vessel. Then an overpressure of 125% of the rated pressure shall be applied within 1 minute and maintained for 2 hours. Subsequently the overpressure shall be reduced to 0.3 bar within 1 minute and maintained at this pressure for 1 hour. The watches shall then be removed from the water and dried with a rag. No evidence of water intrusion or condensation is allowed.
*Resistance to thermal shock. Immersion of the watch in 30 cm ± 2 cm of water at the following temperatures for 10 minutes each, 40 °C, 5 °C and 40 °C again. The time of transition from one immersion to the other shall not exceed 1 min. No evidence of water intrusion or condensation is allowed.
*An optional test originating from the ISO 2281 tests (but not required for obtaining ISO 6425 approval) is exposing the watch to an overpressure of 2 bar. The watch shall show no air-flow exceeding 50 μg/min.

Except the thermal shock resistance test all further ISO 6425 testing should be conducted at 18 °C to 25 °C temperature. Regarding pressure ISO 6425 defines: 1 bar = 105 Pa = 105 N/m2. The required 125% test pressure provides a safety margin against dynamic pressure increase events, water density variations (seawater is 2 to 5% denser than freshwater) and degradation of the seals.

Movement induced dynamic pressure increase is sometimes the subject of urban myths and marketing arguments for diver's watches with high water resistance ratings. When a diver makes a fast swimming movement of 10 m/s (32.8 ft/s) (the best competitive swimmers and finswimmers do not move their hands nor swim that fast[1]) physics dictates that the diver generates a dynamic pressure of 0.5 bar or the equivalent of 5 meters of additional water depth.[2]

Besides water resistance standards to a minimum of 100 metres (330 ft) depth rating ISO 6425 also provides minimum requirements for mechanical diver's watches (quartz and digital watches have slightly differing readability requirements) such as:[3]
*The presence of a time-preselecting device, for example a unidirectional rotating bezel or a digital display. Such a device shall be protected against inadvertent rotation or wrong manipulation. If it is a rotating bezel, it shall have a minute scale going up to 60 min. The markings indicating every 5 min shall be clearly indicated.
The markings on the dial, if existing, shall be coordinated with those of the preselecting device and shall be clearly visible. If the preselecting device is a digital display, it shall be clearly visible.

The following items of the watch shall be legible at a distance of 25 cm (9.8 in) in the dark:
*time (the minute hand shall be clearly distinguishable from the hour hand); set time of the time-preselecting device;
*indication that the watch is running (This is usually indicated by a running second hand with a luminous tip or tail.);
*in the case of battery-powered watches, a battery end-of-life indication.
*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.
*Resistance to salty water. The watches under test shall be put in a 30 g/l NaCl (sodium chloride) solution and kept there for 24 hours at 18 °C to 25 °C. This test water solution has salinity comparable to normal seawater. After this test, the case and accessories shall be examined for any possible changes. Moving parts, particularly the rotating bezel, shall be checked for correct functioning.
*Resistance of attachments to an external force (strap/band solidity). This is tested by applying a force of 200 N (45 lbf) to each springbar (or attaching point) in opposite directions with no damage to the watch of attachment point. The bracelet of the watch being tested shall be closed.
*Marking. Watches conforming to ISO 6425 are marked with the word DIVER’S WATCH L M or DIVER'S L M to distinguish diving watches from look a like watches that are not suitable for actual scuba diving. The letter L indicates the diving depth, in metres, guaranteed by the manufacturer.

Diver’s watches for mixed-gas diving:

Diving at a great depth and for a long period is done in a diving chamber, with the diver spending time alternately in the water and in a pressurized environment, breathing a gas mixture.
In this case, the watch is subjected to the pressure of the gas mixture and its functioning can be disturbed. Consequently, it is recommended to subject the watch to a special extra test.

ISO 6425 defines a diver’s watch for mixed-gas diving as: A watch required to be resistant during diving in water to a depth of at least 100 m and to be unaffected by the overpressure of the mixed gas used for breathing.
The following specific additional requirements for testing of diver's watches for mixed-gas diving are provided by ISO 6425:
*Test of operation at a gas overpressure. The watch is subject to the overpressure of gas which will actually be used, i.e. 125% of the rated pressure, for 15 days.
*Then a rapid reduction in pressure to the atmospheric pressure shall be carried out in a time not exceeding 3 minutes. After this test, the watch shall function correctly. An electronic watch shall function normally during and after the test. A mechanical watch shall function normally after the test (the power reserve normally being less than 15 days).
*Test by internal pressure (simulation of decompression). Remove the crown together with the winding and/or setting stem. In its place, fit a crown of the same type with a hole. Through this hole, introduce the gas mixture which will actually be used and create an overpressure of the rated pressure/20 bar in the watch for a period of 10 hours.
*Then carry out the test at the rated water overpressure. In this case, the original crown with the stem shall be refitted beforehand. After this test, the watch shall function correctly.
*Marking. Watches used for mix-gas diving which satisfy the test requirements are marked with the words "DIVER’S WATCH L M FOR MIXED-GAS DIVING". The letter L indicates the diving depth, in metres, guaranteed by the manufacturer.

The composition of the gas mixture used for the test shall be given in the operating instructions accompanying the watch.
Most manufacturers recommend divers to have their diving watch pressure tested by an authorized service and repair facility annually or every two to three years and have the seals replaced.

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Regards, :thumbup:
Jim

Credit: Taken from/Wikipedia encyclopedia 2010
 

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Thanks Jim! Both of your posts on ISO standards hopefully will clarify some questions we've had recently.
 

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Tried buying ISO 6425 from their website the other day, but they have some extra code needed for use of Mastercard meaning i need to call the bank, but can not as they dont speak English.

With the Mixed Gas Divers add on to ISO 6425 it states the watch needs to be tested in Helium enriched
gas, theoretically you would need to use the the deepest Helium mix on the Sat tables as they cut off well before the depth of most of these watches.

So lets say Rolex for example with their new Deep Sea test at Comex to 3900M each and every Deep Sea, which they do by the way.
Why Rolex does not claim to test to ISO 6425 Mixed Gas Diving, they tend to market their watch in that way being the " commercial divers" watch.
But given the fact they would need to test to 125% of 3900M in the DRY, using Helium enriched gas, then why would they need Comex to test to a lesser depth?
They dont market Comex like they used to, and Comex is not the company it was of course.
So its a fair assumption Rolex do their own tests and dont follow ISO.

So if they dont, what chance does any other company actually follow this standard?
I am under the impression Seiko might for one model, but then that does not say 6425 anywhere?

Does anyone know of any watch tested to ISO 6425 with the mixed gas ad on?
 

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Discussion Starter · #5 ·
Hello t20569cald...Well I've done some commercial wetwork at depth, so I can help

answer a few of your questions I hope!

I'll try to reply within your various topics below in blue font...

Tried buying ISO 6425 from their website the other day, but they have some extra code needed for use of Mastercard meaning i need to call the bank, but can not as they dont speak English.

Well if the watch you were checking into was from the land of the Swiss, and be it a Rolex or other high grade diver, I'm sure ones (Visa or MC) card would have to have enough of a "Power Reserve" to cover the retail price that one would require in such fine cusine.

With the Mixed Gas Divers add on to ISO 6425 it states the watch needs to be tested in Helium enriched
gas, theoretically you would need to use the the deepest Helium mix on the Sat tables as they cut off well before the depth of most of these watches.

I agree, it would need to be tested in a Helium environment and I'm sure that's what exactly is done with the proceedures, but I also don't think that the deepest Helium saturation would have to be used for each watch in testing; One would expect that a 300m saturation divers watch would be tested to the saturation & pressure to and somewhat beyond 300m's in order to certify said watch.
The pressure testing in the Helium sat tank would be performed at a variable rate for the watch being tested, that being that the higher the depth rating of the watch tested to be certified, and thus a higher He saturation level would be used in direct relation to the increased depth rating of the watch being certified.

So lets say Rolex for example with their new Deep Sea test at Comex to 3900M each and every Deep Sea, which they do by the way.
Why Rolex does not claim to test to ISO 6425 Mixed Gas Diving, they tend to market their watch in that way being the " commercial divers" watch.
But given the fact they would need to test to 125% of 3900M in the DRY, using Helium enriched gas, then why would they need Comex to test to a lesser depth?
They dont market Comex like they used to, and Comex is not the company it was of course.
So its a fair assumption Rolex do their own tests and dont follow ISO.

I can see and understand the basic argument you have here, but then again I'm sure the technology exsist to test to those ratings and even beyond the rated watches proposed depth, and it's not unusual to think that 5000m has been hit and years ago from my recollection.
I believe that Comex adheres to and can be aloud to exceed the ISO standards if they so choose to, but it's a given that any manufacturer has to or in addition to, abide by the ISO standards testing authority which is monitored I'm sure.

So if they dont, what chance does any other company actually follow this standard?
I am under the impression Seiko might for one model, but then that does not say 6425 anywhere?

Yes Seiko is one that surely does follow and abide by the ISO testing standards, and they follow the marking proceedures in all there ISO rated divers.
There is no rule that states the watch must be marked as (ISO Certified or Meets ISO Standards) as written, but in fact the acceptible and stated markings on a certified ISO divers watch must say: Divers/Scuba Divers/Professional Diver or be marked with the appropriate internationally accepted "Bar Rating" I believe & for mixed gas divers: /He Resistant/He Safe/Saturation Diver, or similarly used terminology depending on manufacturer and geographic area.

Does anyone know of any watch tested to ISO 6425 with the mixed gas ad on?

Yes, any watch as I stated above and marked as such is supposed to be tested under the ISO mixed gas standards. Seiko & Orient and Citizen have more than a few dive watches that meet the ISO Helium standards and have been certified as such.
A few being: the Seiko SBDX001 Marine Master 300m. the Spring Drive 600m diver, the 600m & 1000m Tuna series divers and others. The Citizen AutoZilla 300m & 1000m Divers, the Orient Star 300m Pro diver.

The Vintage Citizen quartz 1300m Titanium Diver below is from the mid to late 1980's, and it passed certification to well beyond it's factory rating during production, and is He resistant certified.

Well I agree with some of your points and appreciated being able to reply back to you here, and I hope I atleast helped to address a few of your questions you asked the best I could & by no means do I think I know all there is to know of this topic, just that I have studied it from time to time just as we both no doubt have studied Boyals Law & Dive physiology many years ago.

Cheers, :thumbup:
Jim
 

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Not a watch i was buying but rather the ISO pdf from the ISO website.

They would have to test in a Helium environment but lets face it nearly all watches these days are 6 million M deep! So the deepest dive ever done being a chamber dive back in 92 to 701M was not even with Heliox as Hydrogen was added to the mix. I am sure you are aware of that but what i am getting at is the fact 95% of Dive watches these days are 1000M plus so they may as well just use 95% Helium.

Comex has the capability to test to 4000M, you can find that on their website and they also have an exclusive watch testing deal with Rolex, so while they will test other things for you, they will not test watches. I spoke to them twice regarding this.
So point being is if they have 4000M of testing available, they cant test to 125% of 3900M for 15 days then bringing it to the surface in under 3 min, they just dont have the equipment.
So while of course its possible to build the equipment, they dont have it and it would stand to reason if they dont have it then neither do Rolex. Which would mean they either go somewhere else to test, or they more likely do not bother.

You seem certain of Seiko testing to these standards, but honestly i have not come up with it on google. I will look harder today for it, but i have not seen it yet.

An important point i think here, is to have " divers" or He safe on the dial or case is not regulated by the ISO, and for example the Chinese made Tauchmeister has He safe on the back and there is no way they tested that! They way i now understand it, is you can use ISO as the marketing bit if you test and are certified by their standard but they can not stop you using Diver on the dial.
So i am yet to see a watch, that says ISO 6425, or the sales literature to claim they do.
 

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Discussion Starter · #7 ·
Great discussion that I enjoyed, and I can see and understand your points of which

I can agree with some of them no doubt.

Yes, there are some 3rd tier makers out there that no doubt mark there items as meeting the required standards that do not meet them. They break and disregard the international rules and standards of testing to sell units and the dollar is the bottom line.
The majority of makers of quality and relied upon name brands I'm sure abide and adhere to the standards of ISO and Comex as prescribed, and one really need not worry with there professional rated divers watches at all.

I also agree about the max pressure and saturation rich testing, while the highest rated divers could not possibly be tested to those extream 125% over pressure depths in general.

I also agree and would say that some of these guidelines need to be revamped and made stern to ensure a products reliability and meeting the depths and saturation standards as marked.

I know that the current & vintage seiko 300m & 600m & 1000m divers watches of current production to years ago met and exceeded the standards of the day, and exceed them today both in pressure and depth ratings as well as Saturation standards. The vintage 7549 quartz 600m professional Tuna was strapped to the side of a submerine and exceeded the 600m rating by far and that was back in the late 1970's.
I'm also sure that many of the quality swiss makers also have no trouble making the standards and testing proceedures they adhere to both ISO & Comex, so one has no need to worry about there ratings at all AFAIC.

I enjoyed the chat and your intense interest in this topic indeed, and thanks for the great replies!

Happy 4th of July!!! :thumbup:
Semper Fi-

Jim
 
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