I think many have heard a thousand times that of watches with water resistance of the "protection from splashes" ("water resistant") to 5 atmospheres (50 meters) are not suitable for swimming, and swimming are suitable only watch with water resistance to 10 atmospheres (100 meters) and more. I'll try to briefly explain the difference between bryzgozaschita at 5 atm of bryzgozaschity to 3 atm, and why water resistance watches with up to 200 meters are not suitable for diving with an aqualung. But be consistent.
There are different systems of notation watertightness hours - meters, bars and atmospheres. But they all mean roughly the same 1 bar = 1 atm = 10 m. That is 1 bar is equal to 1 atmosphere and conventionally equated to dive to 10 meters. Is it equal to the actual facts, we consider in detail below.
Water resistant, 3 atm, 3 bar, 30 meters - bryzgozaschita, water resistance 3 atmospheres or 30 meters.
These markings are equivalent and, in most cases, the mean for consumers is that the watch is sealed except for the crown. That is, the hours will not withstand immersion in the bottom of the glass with water. Checking the quality of these hours as a rule is to check the compression with a force of three atmospheres. Naturally, without dipping into the water. There are rare exceptions in accordance with ISO 2281, even on the clock marked 30 meters Crown hours must be sealed.
But this practice is uncommon. Yet even with such a clock marking and without sealing the crown is more than enough reserved for use in daily use - a common situation in human hands brushing down. Given that the majority of hours are designed to be worn on the left hand (ie crown down), then even a strong enough rain threatens not splash-proof watch on your hand.
Water resistant 5 atm, 5 bar, 50 meters - Water-resistant to 5 atmospheres.
Starting with this labeling standard involves sealing the crown hours. That is, they must withstand full immersion under water. But for swimming this watch is still in most cases are not suitable. Why? It's very simple. Standard quality checks are carried out in laboratory conditions where the clock has exactly the pressure of 5 atmospheres, and not a drop more.
The water pressure in the pipes of water supply - to 8 - 10 atmospheres. For example when you jump into the water on cotton water can create the peak load is ten times more moisture to get inside the clock. That is not looking for a good water resistance watch marked "Water-resistant to 50 meters" can not withstand even a shower in the bathroom, not to mention the more serious trials "fight."
Water resistant 10 (20) atm, 10 (20) bar, 100 (200) meters - water resistance to 100, 200 or more meters (10-20 atmospheres or more)
Implies a willingness to watch the actual water conditions, and even (in the case of water resistance to 200 meters or more) in some tests. But they are still not suitable for diving with an aqualung. . Watches suitable for scuba diving should be marked "diver's", which means that their specific certification. According to the standard of this show once with water resistance, for example: "diver's 200 m".
This, we briefly touched upon the watertightness. Next, we consider them more detailed that would finally learn to separate the wheat from the chaff, and to distinguish normal marketing moves in the sale of watches, from the real "workhorse" diver.
In horology, there are two standard notation for watertightness hours. First - ISO 2281 - for hours for everyday wear. The second - ISO 6425 - for the hours designated for diving. Let us examine them.
ISO 2281 - standard for waterproof watches.
This standard was developed only for the hours designated for normal daily use during exercises under water for a short period under the conditions of unstable temperature and hydraulic pressure. The standard provides for random testing hours of one party, rather than each model separately.
Testing involves the following steps:
Dive hours in water at 10 cm for 1 hour.
Dive hours in water at 10 cm with the force of 5 N perpendicular to the crown and buttons (if any) within 10 minutes.
Dive hours in water at 10 cm with the temperature between 40 ° C, 20 ° C and then 40 ° C. At each temperature, the watch is within five minutes, the transition between the temperatures of no more than five minutes. During and after the test is not allowed condensation, and, especially, water penetration.
Dive hours in the water in the chamber and apply them to the rated pressure for 1 hour. Not allowed condensation and water penetration into the watches.
Checking the excess hours to the rated pressure of 2 atm.
Watches should not show streamlined than 50? G / min
Strap test is not required
The test is not required for corrosion
Test negative pressure is not required
Test for resistance to shocks and magnetic fields are not required
In addition to the test with the temperature all the other tests are ISO 2281 should be conducted at a temperature of 18 ° C to 25 ° C. ISO 2281 defines the pressure as 1 bar = 105 Pa = 105 N/m2.
ISO 6425 watches of diving
ISO 6425 defines a diver watches as: watches, designed to be waterproof during a scuba diving at depths of at least 100 m and remain at the same time control system. Diving watches are tested in still water for at least 125% of rated pressure (that is stated on the clock).
Thus watch with water resistance of 200 meters are waterproof to a depth of not less than 250 meters of immobile water. Testing of water resistance is significantly different from the clock is not for diving, at least by the fact that the standard provides a full scan of each unit of watches.
Testing according to ISO 6425 includes the following checks:
The reliability of the water. Watches during the test shall be immersed to a depth of 30 cm, + / - 2 cm for 50 hours at 18 ° C to 25 ° C and all arrangements should continue to function correctly. Check for condensation is performed before and after the test, which would ensure that the results associated with this test.
Test condensate. The clock must be placed on the hot plate temperature between 40 ° C and 45 ° C, until the clock has not reached the temperature of the plate (usually enough from 10 to 20 minutes, depending on the type of hours). Then the irrigation water temperature of 18 ° C to 25 ° C on glass watches. After approximately 1 minute after the glass surface should be wiped with a dry cloth. Any watches that have condensation on the inner surface of the glass must be destroyed.
Resistance of winding heads, and other control devices to the external force. During the test watches should be subjected to excess pressure in water at 125% rated waterproof for 10 minutes and to the external force of 5 N perpendicular to the crown and buttons (if any). Test the condensate must be performed before and after the test to ensure that the results associated with this test.
Water-resistant to overpressure in the water and the pressure. Watches during the test shall be immersed in water contained in a pressure chamber. After that, during the 1st minute to be pumped overpressure of 125% of rated waterproof and maintained for 2 hours. Subsequently, the excess pressure must be reduced to 0.3 bar for 1 minute and maintained at this pressure for 1 hour. The clock must then be pulled from the water and dried. Not be any condensation and water penetration watches.
Resistance to thermal shock. The test involves immersing o'clock at 30 cm ± 2 cm in water at these temperatures (10 minutes each): 40 ° C, 5 ° C and 40 ° C again. The transition time from one dive to another shall not exceed 1 min. No evidence of water intrusion or condensation is not allowed.
In addition to the test with the temperature all the other tests are ISO 6425 should be conducted at a temperature of 18 ° C to 25 ° C. ISO 6425 defines the pressure as 1 bar = 105 Pa = 105 N/m2.
The required 125% of th test pressure provides a margin of safety against such events as the dynamic pressure increase, the change in density of water (sea water for 2 - 5% denser than freshwater) and degradation of the seals.
As for the dynamic pressure caused by the movement - that is nothing more than myth and marketing approach to selling o'clock with a greater degree of water protection. When the diver swims fast a speed of 10 m \ in (32.8 ft / s) (the best swimmers can not swim and is close to that speed), the physics dictates that the diver produces a dynamic pressure of 0.5 bars is equivalent to 5 meters more of water depth.
In addition to the standard ISO 6425 waterproof and provides the minimum requirements for mechanical diver's o'clock (and quartz, and a digital clock has its own specifics), such as:
The presence of pre-note the time a device such as a unidirectional rotating bezel with marking time (so-called "timer diver") or a digital display. Such a device must be protected against careless or improper rotation manipulation.
If it is a rotating bezel, then it should be small scale, suitable for 60 minutes. marking, with clearly defined five-minute intervals. Markings on the bezel, if applicable, should be coordinated with those of the device and must be clearly visible. If the device is a digital display, it should also be clearly visible.
The following items should be readable in the dark from a distance of 25 cm:
Time. The minute hand should be easily distinguishable from the watch.
Setting the time on the stopwatch timing devices
Indication of the fact that the clock is (usually second hand movement with luminous mark)
In the case of o'clock with a battery charge indicator should be a function or "end-of-life" (warning of low battery)
The resistance of magnetization. This is tested by three-quarters o'clock in a magnetic field strength 4,800 A / m. The clock must maintain accurate to at least + / -30 sec / day as before the test.
Shockproof. Tested by two strokes (one on the side at 9 o'clock, and the second glass is perpendicular to the dial). Usually applied by a hammer blow of hard plastic set like a pendulum so that we could control the force of impact. Usually it is a hammer weighing 3 kg at a rate shock to 4.43 m / sec. Changes to the accuracy of the permitted up to + / - 60 sec / day.
Resistance to salt water. During this test watches is placed in a solution of 30 g / l NaCl and left there for 24 hours at a temperature of 18 ° C to 25 ° C. This test solution has a "salinity" comparable to the sea. After the test case and bracelet is checked for possible changes. Moving parts, such as a rotating bezel, after the test must operate normally.
Resistance to external efforts further details (check strap / bracelet for durability). Tested the use of force 200 N to each link (and the place of attachment) in opposite directions. No damage to either o'clock or bracelet attachment sites are not allowed. Bracelet watch in the test must be closed (for comparison, the official website stated that Tissot watches them pass a similar test in an effort to 50N).
Marking. Watches have passed the ISO 6425 are marked with the word DIVER'S WATCH LM or DIVER'S LM that would allow to distinguish watches o'clock of water resistance with a similar but not suitable for diving. The letter L shows the depth of the dive in meters, guaranteed by the manufacturer.
But diving with breathing mixture even the most severe of these measures may be small, so the ISO 6425 provides a number of additional tests for the o'clock destined to be companions of man in the most extreme conditions.
Watch for diving with breathing mixture.
This part provides a standard watches for use in an underwater bell with alternate dipping into the water and finding the pressure in the breathing mixture. Since helium molecules are smaller than water molecules, they can pass freely through the body, even waterproof o'clock and disturb their operation. To test the ability to withstand o'clock such tests are ISO 6425 provides a number of additional tests, such as:
Test operations in the gas overpressure. Watches subject to overpressure gas, which will actually be used for 125% of rated pressure, at least 15 days. Then made a rapid reduction in pressure to atmospheric pressure that must be satisfied for the time not to exceed 3 minutes. After this test clock should function correctly. Quartz watches have to function normally during and after the test. Mechanical watches should function normally after the test (usually a power reserve of less than 15 days).
Internal pressure test (simulation of decompression). The crown is removed together with the pivot for the plant and the transfer time. In its place is installed the crown of the same type with the hole. Through this hole, the gas mixture is introduced, which will be actually used and create a nominal overpressure davleniya/20 bar in hours for a period of 10 hours. Then the test is performed in the nominal water overpressure for which the original crown shall be set back. After this test clock should operate normally.
Marking. Watches have passed the ISO 6425 for use with a mixture of marked respiratory word "DIVER'S WATCH LM FOR MIXED-GAS DIVING". The letter L shows the depth of the dive in meters, guaranteed by the manufacturer. The composition of the gas used during the test must be specified in the instructions to watch.
Despite the above-said, many manufacturers do not o'clock too reluctant to follow even with ISO 2281, not to mention the ISO 6425. Sin as these smaller companies, who can not afford the costs associated with the introduction of such standards in production, and large - that just are not too sensitive about the production.
Most often, there is complete absence of sealing the crown on the watch with water resistance to 30 meters, because it is not necessary to actually submerge such a watch even a glass of water. Many manufacturers of the same problem and there is marked at 50 meters.
Producers of the same quality control that meets the above standards is pleased to point out in the instructions to watch. Often, on the contrary, use of people's ignorance of standards and point to watch with water resistance of over 300 meters waterproof standard ISO 2281, which, as described above, for diving is not relevant.
Here is briefly what is actually hidden behind high-sounding slogans such as "waterproof to xx feet" and what is behind the accepted conventions of the final o'clock of the owner of what are often unable or unwilling to tell as sellers and manufacturers of watches.
Finally recall only that, in practice, the survival of o'clock will depend not only on the depth of water, but also on the age of gaskets, past injuries, temperature, and additional mechanical shocks and vibrations. Most manufacturers recommend divers to check the clock on the water resistance indicated in the authorized service centers and workshops each year and every two to three years to make the replacement pads. This can be done easily at the same time replacing the batteries in quartz watches or preventive cleaning of mechanical watches.
In conclusion, some recommendations as to maintain water resistance up to par.
1. The main thing to remember about temperature conditions even if the clock actually hold 30 bar (300 M) as to overheat and can not be supercool. This is for the fans to leave on the torpedo in the summer or in the glove compartment for the winter. Seals deteriorate very quickly. In the sauna with the clock can not go even if they are 100 bar, rubber holds only pressure from overheating spoils that would not tell anyone.
2. Various kinds of solvents do not wash.
3. With the clock tower not to dive, even if it is 1 meter. To jump from the tower as well as for trips to the sauna there is no o'clock.
Carving on the lid and the head is not a guarantee of integrity, but the preferred option, allows you to put the squeeze on for a while even if the gasket is not very much.
And most importantly, what not to say any manufacturer or vendor but knows every watchmaker - if your watch apart from the crown, there is also a button - these same buttons in the water can not be pressed.
That is perhaps all the recipes of happiness in their observance of what is written on the watch will be long enough to be true.
