General information on waterproofness as of DIN 8310

What means waterproof

Waterproofness is not a permanent feature; It should be checked every year and especially before extrem exposure to water because the implemented sealing elements wear off in daily usage. Watch cases are made of different perfectly fitted materials that, in case of temperature fluctuations, can have different coefficients of expansion.

There are special constructions with implemented seals, to provide waterproofness for certain demands. Those seals are subject to a natural aging process. They are affected by, perspiration and other acids.

DIN 8310

DIN 8310 regulates criterias for the construction and test pressures that new watches have to be able to sustain. The resistivity is measured in bar and recorded on the bottom of the case.

Water-resistant

Water-resistant watch cases, are resilient to perspiration, water drops, rain, etc.. Put under water for more than 30 minutes, in a water depth of one meter, they have to be able to withstand the infiltration of water. Those watches are made for normal, everyday use and are not allowed to be used in conditions where temperature and water pressure vary greatly.

Test pressure

The test requirements are tightened, if an additional information is given about the pressure like, for example, 3 bar. The pressure indication 3 bar is the definition of the test pressure and is not be be confused with the diving depth. A test pressure of 3 bar will be achieved in 30 m water depth.

The jump into the water

Swimming or jumping into the water can, for a short amount of time, cause a higher pressure on the sealing elements as is defined by the guaranteed test pressure.Particularly at risk are the watches, if you jump into the water right after a long sunbath. In this case, the impact pressure and the depression of the cooling add up , which can easily lead to damages.

Battery change

In case of a battery change it is important to check the performance characteristics of DIN made watches, as well as the sealing elements and, if necessary, to exchange them.

In the following spreadsheet you can see the activities you can do with your watch, and which you should rather not do, if you want to enjoy your watch a little longer.

Indication case bottom	Indication dial	to wash/bathe, splashes	to shower	to take a bath	to swim	to snorkel	to dive
none	none	no	no	no	no	no	no
Water-resistant 3 bar/atm	none	yes	no	no	no	no	no
Water-resistant 5 bar/atm	50 m	yes	yes	yes	no	no	no
Water-resistant 10 bar/atm	100 m	yes	yes	yes	yes	yes	no
Water-resistant 20 bar/atm	200 m	yes	yes	yes	yes	yes	yes