What is IP Code?

The degree of protection for iButtons is specified with IP56. However, what is behind this IP Code and what does it mean for practical use?

IP Standard

The IP Code is defined in DIN EN 60529. This standard specifies definitions for degrees of protection provided by enclosures of electrical equipment as regards:

• Protection of persons against access to hazardous parts inside the enclosure;
• Protection of the equipment inside the enclosure against ingress of solid foreign objects;
• Protection of the equipment inside the enclosure against harmful effects due to the ingress of water.

Not part of this standard are measures against other, partially similar external influences such as corrosion, etching solvents, freezing or condensing humidity.

Meaning of Code Numbers

The first code number indicates to which extend the enclosure is protecting persons from access to dangerous parts and simultaneously to which extend the enclosure provides protection against ingression of foreign solids. In general, the requirements of the lower degrees of protection have to be adhered to as well. Is the degree of protection of the first code number not to be specified, the code number has to be replaced by an X.

Code Number	Description
0	Non-protected
1	Protected against foreign solids, 50 mm diameter and greater
2	Protected against foreign solids, 12.5 mm diameter and greater
3	Protected against foreign solids, 2.5 mm diameter and greater
4	Protected against foreign solids, 1 mm diameter and greater
5	Dust-protected
6	Dust-tight
Table: Degrees of protection against foreign solids, first code number

The second code number indicates the degree of protection against the ingress of water. Up to code number 6 the requirements of lower degrees of protection have to be adhered to as well. The code numbers 7 and 8 are independent and have to be stated separately.

Code Number	Description
0	Non-protected
1	Protected against falling water drops
2	Protected against falling water drops, when enclosure tilted up to 15°
3	Protected against spraying water
4	Protected against splashing water
5	Protected against water jets
6	Protected against powerful water jets
7	Protected against the effects of temporary immersion in water
8	Protected against the effects on continuous immersion in water
9	Protected against high pressure and high water jet temperatures
Table: Degrees of protection against water, second code number

IP Code of iButtons

The degree of protection of iButtons, series DS1921, DS1922 and DS1923 was defined by the manufacturer as IP56. For some types the degree of protection was certified by an independent test laboratory. As the table above shows, the iButtons are protected against dust and powerful water jets. The requirements of all lower degrees of protection are met as well.

Frequently the stating of the IP Code lead to false assumptions. Users assume, for example, the degree of protection can be transferred to similar conditions and that it is guaranteed permanent.

The 6th code number of the IP standard indicates, the enclosure withstands a powerful water jet for a few minutes. If the degree of protection is effective on hot water or other liquids is not specified. Furthermore the degree of protection refers always to equipment in as good as new condition.

The manufacturer of iButtons explicitly points out that the degree of protection IP56 is valid only for products in as good as new condition and it has to be considered that the (degree of) protection deteriorates gradually.

IP Code in practical

On close consideration iButtons offer only rudimentary protection against water. In practice data loggers are exposed to much tougher conditions. Even the open air placement in moderate climate for several months or years proves to be a tougher challenge for the enclosure then any test according to the IP standard. The subject of humidity is not even dealt with. The manufacturer's provided IP code has limited relevance in the case of iButtons.

Waterproof iButtons