Water Resistance-What Does It Mean? 



by Neil Rosenfeld



Watches are often worn in places that expose them to water. How does
this affect the watch and what should we expect in terms of resistance to
water? A common misconception is the term "waterproof". This term is no longer
used in conjunction with the ability of a watch to withstand exposure to
water. No watch is truly waterproof. The safe exposure to water of a watch
depends on many factors. Testing is done in both a wet or dry pressure
environment. Wet testing is done under pressure, but without motion of the
watch or wearer since this can vary so much from person to person.



The proper term to use is "water resistance", not "waterproof". The
measure of the ability to resist water penetration into the watch is a
function of temperature and pressure. It is common to see watches rated in
atmospheres of pressure (ATM) or measured in feet or meters of depth. For
example, a watch rated resistant to water at a pressure of 1 atmosphere is
rated at 33 feet or 10 meters. This means that the watch is safe to use where
it may be splashed or exposed to perspiration. An occasional accidental
immersion may be safe. The key here is that the watch cannot be exposed to
water that is under any pressure.



A watch rated water resistant at a pressure of 3 atmospheres is equal to
30 meters or 100 feet of resistance. It is safe from splashes and occasional
immersion in water, but not safe to swim with.



At 5 atmospheres (165 feet or 50 meters) a watch is safe to wear in
shallow water, but not safe for scuba diving. A rating of 10 atmospheres (330
feet or 100 meters) allows wear in a pool, for sports or poolside diving. At
15 atmospheres(500 feet or 150 meters) your watch is suitable for snorkeling,
diving in a pool and wearing during sports play.



At 20 atmospheres (660 feet or 200 meters) allows for use in snorkeling,
and scuba diving at depths that don't require helium. Watch water resistance
even goes up to 1,000 meters. This is a designation for a watch that is
suitable for deep sea diving. Some of these watches come with a helium release
valve that allow helium that has entered the watch during decompression from a
deep dive, to escape from the watch. This keeps the watch from exploding from
the pressure. Of course, most of us will never have to worry about this.



These ratings are not absolute. They depend on the temperature as well.
Never wear a watch of any rating in a hot tub. The heat will deform the seals
that protect the mechanism and cause leakage. The age of a watch is also
important as the seals can become brittle with age. Chemical exposure can also
degrade the seal integrity causing problems. Whenever a watch is opened (for
inspection or battery change for example), the seals must be inspected and
replaced if necessary.



Knowing the limitations of your timepiece can protect your investment
from water damage. Understanding what water resistance ratings mean is the
first step.With proper care, your watch will last for many years.





The author is webmaster at a site that carries CTI
Watches and another that carries Tritium
Watches by Luminox and Smith & Wesson.



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