Since there isn't a copy of ISO 2281 in the reference section, here is the text:
Horology - Water-resistant watches
This International Standard specifies the requirements and test methods for watches designated as "water-resistant" and marked accordingly, with or without an additional indication of an overpressure.
lt does not apply to divers’ watches, which are specified in ISO 6425
2 Normative reference
The following Standard contains provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the edition indicated was valid. All Standards are subject to revision, and Parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent edition of the Standard indicated below. Members of IEC and ISO maintain registers of currently valid International Standards.
ISO 2859-1: 1989, Sampling procedures for inspection by attributes - Part 1: Sampling plans indexed by acceptable quality level (AQL) for lot-by-lot inspection.
Watches bearing the designation "water-resistant" with or without an additional indication of an overpressure are intended for ordinary daily use and are resistant to water during exercises such as swimming for a short period. They may be used under conditions where water pressure and temperature vary. However, whether they bear an additional indication of overpressure or not, they are not intended for submarine diving.
Watches bearing the designation "water-resistant" shall comply with the requirements given in either 4.1 and 4.3, or in 4.2 and 4.3.
4.1 Resistance to air overpressure
The flow rate of air shall not exceed 50 μg/min.
Testing shall be carried out in accordance with 6.2.1.
4.2 Resistance to water overpressure
There shall be no condensation visible on the inside surface of the glass after conducting the condensation test given in 6.2.2 before and after the tests given in 6.2.3 to 6.2.6.
4.3 Resistance against temperature and mechanical stress
There shall be no condensation visible on the inside surface of the glass after conducting the condensation test given in 6.2.2 before and after the tests given in 6.2.3 to 6.2.5.
This International Standard may be applied for piece-by-piece inspection or by sampling. In this case, sampling shall be carried out in accordance with ISO 2859-1.
The tests specified in 6.2.3, 6.2.4 and 6.2.5 are compulsory on at least one Sample of the examined lot.
6.1 Test conditions
6.1.1 Before testing, the operative Parts shall be operated and set back to their normal position.
6.1.2 Throughout the period of testing, the ambient temperature shall be between 18 degrees C and 25 degrees C. The water temperature shall be equal to the ambient temperature except for the test given in 6.2.5 .
6.2 Test procedures
The sequence of the tests is optional. The condensation test shall be conducted before the test given in 6.2.3 and at the end of the test sequence.
Condensation tests between each specified test are optional.
6.2.1 Resistance to air overpressure
Subject the watch to an air overpressure of 2 bar and measure the flow rate of air entering the case.
NOTE 1 Comparable test procedures, for example using inert gases, are permitted.
Watches showing a flow rate of air greater than 50 μg/min do not satisfy the requirements of 4.1, and shall not be subjected to the subsequent tests.
6.2.2 Condensatlon test
Place the watch on a heating cushion controlled at 40 degrees C to 45 degrees C until the temperature of the watch is equal to that of the heating cushion (usually, a heating time of 10 min to 20 min is sufficient, depending on the type of watch). Place a drop of water of 18 degrees C to 25 degrees C on the watch glass.
After about 1 min, wipe the glass with a dry rag.
The watch presenting condensation on the inside surface of the glass does not satisfy the requirements of 4.2.
If the watch case was closed in a humidity saturated atmosphere, the condensation test may result in a type of condensation which is not caused by a possible lack of water-tightness of the watch case. lf this occurs, the watch shall be dried and shall be resubjected to the condensation test.
6.2.3 Resistance when immersed in water at a depth of 10 cm
Immerse the watch in water at a depth of (10 +/- 2) cm and leave it for 1 h.
6.2.4 Resistance of operative parts
Immerse the watch in water at a depth of 10 cm for 5 min, and apply a forc of 5 N perpendicular to the axis of the crown and buttons. See figure 1.
6.2.5 Resistance to different temperatures
Immerse the watch at a depth of 10 cm successively
- in water at 40 degrees C for 5 min;
- in water at 20 degrees C for 5 min;
- in water at 40 degrees C for 5 min;
The transfer time between the immersions shall not exceed 1 min.
6.2.6 Resistance to water overpressure
lmmerse the watch completely in an adequate container filled with water. Within 1 min, apply an overpressure equivalent to the indicated value (see 7.2), or to 2 bar in case where no additional indication is given. Maintain this pressure for 10 min. Then reduce the overpressure to the ambient pressure
within 1 min.
Watches which satisfy the requirements specified in clause 4 shall be marked with one of the following terms in the appropriate language:
- English: water-resistant
- French: étanche
- Russian: водокепроницаемые
- German: wasserdicht
- Japanese: 防水腕時計
- Chinese: 防水
For the above languages only the expression given
shall be used. Equivalent expressions are permitted
for other languages, but one only per language.
7.2 Additional Indication
In addition to the term "water resistant", watches may be marked wifh an indication of the test overpressure given as a pressure in bar (at least 2 bar) or in the sense of a Substitute as a depth in metres (at least 20 m). These indications however do not correspond to a diving depth but refer to the pressure at which the water overpressure test was conducted.
1. ISO 64251984, Divers’ watches.
2. 1 bar + 10^5 Pa