Every Brunoff must undergo a series of tests for water resistance before it reaches the sales outlet. The first test places the timepiece under high air pressure, to ensure that air cannot find its way into the watch housing. The following test takes it through wide temperature variations in a damp environment, to ensure the total absence of water condensation inside the watch glass. The final hurdle which must be overcome is the diving test: several hours under water at high pressure, to simulate the depth for which the watch has been certified, and guaranteed to withstand.
**Important! The water resistance rating of our watches is based upon laboratory pressure tests, the conditions under which the timepiece is tested represent a basis for minimum protection that a water-resistant watch should give.
It should also be understood that water resistance cannot be guaranteed for an indefinite length of time. It may become compromised by accidental shock or impact to the crown, push-button or other areas. For this reason, we recommend that you have your timepiece checked for water resistance by an authorized Brunoff Service Center annually, and have any faulty component replaced, if necessary. One should not, under any circumstance, attempt to open a complex, modern watch on one's own.
Introduction
A watch rated as Water Resistant may come in contact with water to a predetermined extent. Most watches have a measurement until which the depth of immersion is safe. It is important to remember that a water-resistant rating is based upon optimum conditions in a laboratory. Real life experience & aging of the gaskets will effectively decrease the manufacturer's specifications of water resistance over time. When water comes in contact with the movement, it is the worst scenario that can happen to a watch - thus we strongly suggest that you always work well within the parameters and recommendations also have your watch tested at least once a year. DIN 8310 regulates the criteria for construction and test pressures which new watches have to withstand. The resistibility is stated in bar and noted on the housing base.
Water resistance on a watch is obtained by 3 important factors:
1. Case back
- this refers to how the case back is attached to the watch. Snap-on case backs are sealed by pressure and are considered the least water resistant. The slightest nick in a case or deformity in a gasket (which will happen over time) will allow water to penetrate the case. Generally, these watches will have a water resistance of 30m/99ft maximum - which allows for contact with water but not immersion. Case-backs attached with screws would be the second level of water resistance. Having the case back attached with screws allows for a much tighter seal than a snap-on case back, however a deformity in the gasket will still allow water to penetrate. Generally, these watches will have a water resistance of 100m/330ft maximum - which allows for light swimming & immersion in a pool. Screw-in case backs are threaded and screws into the actual case. This creates a double seal, using both the threading & the gasket as a seal. Generally, (although not the rule) diving watches with water resistant ratings greater than 100m/330ft will have this type of case back.
2. Crown
- the single most important factor to ensuring water resistance. The weakest link in a watch for water to penetrate is the crown-stem hole. The stem of the crown is attached to the movement through a hole in the case edge. As the crown is constantly moved to different positions, wound and turned to correct the time, the gasket is constantly compressed, chafed & stressed. The slightest variation in the shape of the gasket or if the crown is not pushed all the way in will allow water to penetrate the watch through the stem hole. Screw-Down Crowns are threaded & screw shut to a matching threaded tube in the case. The crown has a gasket that is compressed & seals the opening when the crown is tightened - thus ensuring water resistance. A screw-down crown is an essential feature for any watch you intend on swimming with. As matter of fact, we do not recommend swimming with a watch that does not have a screw-down crown. No matter if the watch has a screw-down crown & chronograph pushers, the crowns & pushers are never to be pushed, adjusted or opened when the watch is immersed in water - unless otherwise stated by the manufacturer. An additional benefit of the screw-down crown is that the crown is somewhat more protected from accidental knocks.
3. Gaskets:
"O" rings are made of rubber, nylon or Teflon which form watertight seals at the joints where the crystal, case back and crown meet the watch case. If the watch is a chronograph, the chronograph pushers will also have gaskets. Gaskets begin to erode and break down over time, diminishing the water resistance of a watch. It is important to test you watch once a year for water resistance.
Real Life and Water Resistance
When a watch is tested by the manufacturer it is done in a laboratory under optimum conditions, such as a fresh gasket, sitting stationary in a pressured water tank and with still/motionless water. However, real life action will produce completely different results. Here are a few scenarios: Water temperatures in a hot-tub or a hot shower will effect the shape of the gasket seals. Especially if the watch is taken from hot temperatures & immediately plunged into cold water - such as going from a hot-tub into a pool.
Sudden & rapid changes in pressure - such as diving (even shallow diving) into a pool, the force of plunging your arm into the water while swimming, will stress the gaskets for a fraction of a second. If the gaskets are not up to specification they may rupture and cause the watch to take in water.
As the watch ages the seals begin to erode & will not maintain the same water resistance levels.
Water Resistance vs. Water Proof
The U.S. FTC (Federal Trade Commission) which enforces the truth-of-advertising has deemed the term "Waterproof" inappropriate. In their opinion, a watch can never be 100% truly impervious to water, as the gaskets deteriorate over time & exposure, thus reducing the specified depth of water resistance. In the words of the FTC "The word proof connotes a measure of absolute protection that unfortunately does not exist with respect to watches, especially over prolonged periods of time." The FTC has found the term Water Resistant to be more appropriate.
Water Resistance Testing Methods
There are 2 commonly used water-resistance testing methods:
Dry Test - The watch is placed in a chamber and the air-pressure is increased. The machine will detect the smallest variation in the case size. If the case expands, even slightly, then the watch is not water resistant.
Wet Test - the watch is placed in a chamber which is half filled with water and half air. Air pressure is increased while the watch is out of the water, then the watch is slowly immersed into the water. Once the watch is completely immersed, the air pressure is slowly released. If bubbles come out of the watch it means that air seeped into the watch prior to immersion & the watch is not water resistant. This method is generally used as a second test to pin-point the problem area.
ATM or BAR
ATM is short for "Atmosphere" which is equal to 10 meters. Another word for ATM which is commonly used in Europe is BAR - this too is equal to 10 meters.
Interpretation of the Depth Ratings
IMPORTANT: We strongly recommend purchasing a watch with a screw-down crown if you intend on wearing the watch while you are in contact with water.
Our Recommendations
- Have your watch water-tested once a year.
- Do not shower or swim with your watch unless it is rated 100m/330ft & has a screw-down crown.
- Never open, wind or operate the crown while in water.
- Never press the buttons of a chronograph watch while in water - unless otherwise stated by the manufacturer.
- Do not subject your watch to extreme temperature changes.
- Do not subject your watch to sudden & rapid air-pressure changes.
- Do not allow your watch to come in contact with corrosive chemicals, such as abrasive soaps & highly chlorinated water.
- Ensure that the crown is always pushed in, and if you have a screw-down crown make sure it is always tightened. Double-check before immersing in water.
- When changing the battery, it is important to check the performance characteristics of watches manufactured according to DIN and to check the seals accordingly and replace them if necessary.
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