IP67 tracker ratings: can a Bluetooth tag get wet?

An IP67 tracker rating is one of the few numbers on a product page that means something precise, because it comes from a published international standard rather than from a marketing department. It is also routinely over-read. IP67 does not mean waterproof, it does not mean you can swim with it, and it very specifically does not mean it will survive a wash cycle. Here is what the two digits actually certify, and the four situations where the seal stops helping.

The two digits, and what each one certifies

The IP code is defined in IEC 60529, Degrees of protection provided by enclosures (IP Code), whose consolidated edition 2.2 dates from 2013. The letters stand for Ingress Protection, and the two digits are graded independently.

The first digit covers solids, on a scale from 0 to 6. A 6 is the top of that scale and means dust-tight: no ingress of dust at all, tested under vacuum. This is the digit people ignore, and for a tag that lives in a toolbox, a pocket full of grit or a garage it is arguably the more useful of the two.

The second digit covers water, on a scale from 0 to 9. A 7 means protection against the effects of temporary immersion. The test is specific: the enclosure is submerged in fresh water so that its lowest point sits one metre below the surface, and left there for thirty minutes.

That is the whole promise. Dust-tight, plus half an hour under a metre of still, clean water.

What the test does not simulate

This is where the over-reading happens, because the laboratory test is a static one and the real world is not.

• Moving water. Immersion testing uses still water. A jet, a pressure washer or a tap at full flow applies force the 7 says nothing about — that is a different digit entirely on the same scale, and the scale is not cumulative. A device rated IPX7 has not necessarily passed the jet test.
• Hot or soapy water. Detergent lowers surface tension, and heat makes seals expand and the air inside the case expand with them. A washing machine combines heat, chemistry, tumbling and mechanical shock. It is the single most reliable way to kill an IP67 device, and it is where a great many tags on keyrings and in coat pockets meet their end.
• Salt water. Sea water is conductive and corrosive. A short dunk is survivable; a tag that has been in the sea should be rinsed in fresh water and dried thoroughly, and it will still be on borrowed time.
• Pressure and depth. One metre. Not two, not a swimming pool floor, and not a river with any current in it.

There is one more caveat that manufacturers rarely spell out: the rating describes the enclosure when it left the factory. A case that has been dropped hard enough to distort, or opened repeatedly for battery changes and closed carelessly, no longer has the seal it was tested with.

IP67, IP68 and IPX7 side by side

The important row is the last one. IP68 is not a fixed figure: the standard allows the manufacturer to declare the conditions, so an IP68 device is only as good as the depth and duration printed next to it. An honest IP67 tells you more than a vague IP68.

What this means for an IP67 tracker in real use

Run through the situations a tag on a keyring or in a kit bag actually meets:

1. Walked home in heavy rain. Comfortably inside spec.
2. Dropped in a puddle and fished out. Inside spec.
3. Left on a garden table overnight through a downpour. Inside spec.
4. In a bag with a bottle that leaked. Inside spec.
5. Through a 40-degree cotton cycle. Outside spec. Expect a dead tag.
6. Taken swimming in the sea. Outside spec, and corrosive as well.
7. Under a car tyre. No IP rating covers crushing.

Five out of seven is a good result for a sealed plastic case with a removable back, and it is worth knowing which two you are avoiding.

How BlueTag is sealed

BlueTag is rated IP67 to the standard described above: dust-tight, and rated for immersion in one metre of water for thirty minutes. That covers rain, a spilled drink in a rucksack and a dropped-in-a-puddle afternoon. It does not cover a washing machine, prolonged exposure to salt water, or a car tyre, and we say so on the specification rather than leaving you to find out.

The rest of the hardware follows the same logic. There is exactly one thing that opens — the back, and it opens for the CR2032 cell that runs the tag for up to two years — because every additional seam is another path for water. The body measures 36.3 mm across each side and 9 mm through, weighing roughly 10 g, with the key ring hole moulded into it rather than added as a fitting. Bluetooth covers up to 60 m / 200 ft and is what sets the 80–100 dB buzzer off; further out, Apple's Find My network hands you an encrypted position that only your Apple Account can open.

Only Apple phones and tablets on iOS 14.5 and upwards can use it; Android owners get nothing from it. Boxes contain two tags each, UK postage is included, and a box comes to under £15. See the full specification, or read why a tag earns its keep on a wet building site next.

Sources

• IEC — Ingress Protection (IP) ratings
• IEC Webstore — IEC 60529:1989+AMD1:1999+AMD2:2013, Degrees of protection provided by enclosures (IP Code), edition 2.2, 29 August 2013