Every industrial LED work light datasheet carries an IP number, and on most of them the number is doing more marketing than engineering. IP68 and IP69K are the two you will meet most often, and most buyers read them as one scale: 69K must be 68 with something extra.
It is not. The two numbers come from two different standards, describe two different hazards, and a product that passes one has not been shown to pass the other. Specifying the wrong one is the kind of mistake that does not show up until the warranty claims arrive.
We build work lights for OEM lines and fleet buyers, and this is the failure we see most: lamps that pass a submersion test, go onto a machine that gets pressure-washed at the end of every shift, and die within a season. Nothing was defective. The wrong test was specified.
The short answer: IP68 means still water at a depth the supplier chose. IP69K means water at 80 °C arriving at 80 to 100 bar, which is a commercial pressure washer. If the equipment ever meets a pressure washer, IP68 is not the number to buy on.
The Two Ratings Come From Two Different Standards
The IP code itself, and the two digits that follow the letters, are defined in IEC 60529. The first digit rates protection against solids, the second against water. A first digit of 6 means dust-tight, and IP68 and IP69K share it.
Then the scales part company. In IEC 60529 the second digit runs from 0 to 8, and 8 is the top of it. There is no 9, and there is no K suffix anywhere in the document.
The 9K test was written by the German automotive industry as DIN 40050 Part 9, for road vehicles that get steam-cleaned. DIN 40050-9 has since been withdrawn and the test now sits in ISO 20653, the road-vehicle IP standard.
ISO 20653 also writes the code differently. Its own notation puts a K on both digits, so the rating that the market calls IP69K appears in the standard as IP6K9K. They are the same test, and you will see both spellings on datasheets, including two models in our own catalogue.
This has a practical consequence that buyers can use immediately. If a supplier answers an IP69K question by sending an IEC 60529 report, they have sent a report for a standard that does not contain the test they are claiming to have passed. That is worth one polite follow-up email before it is worth a purchase order.
| IP68 | IP69K (IP6K9K in ISO 20653) | |
|---|---|---|
| Standard that defines the test | IEC 60529 | ISO 20653, previously DIN 40050 Part 9 |
| What the water does | Sits still, above the product | Arrives as a jet, at pressure and temperature |
| Parameters the standard fixes | Dust-tight, and immersion more severe than IPx7; depth and duration are agreed between supplier and buyer | Water at 80 °C, 80 to 100 bar, 14 to 16 litres per minute, from 0, 30, 60 and 90 degrees |
| What it does not cover | High-pressure jets of any kind | Prolonged immersion at depth |
| Report to ask for | IEC 60529, with the declared depth and duration on it | ISO 20653, or DIN 40050-9 on older reports |
| Typical duty | Marine deck and submerged fittings, river crossings, rain and spray | Daily washdown: agriculture, construction, refuse, food processing, car washes |
IP68: the Number the Standard Lets the Supplier Choose
The IP68 test submerges the product in still water and checks that nothing got in. The number most people have in mind is one metre for thirty minutes, and that is where the misunderstanding starts, because that figure is the IPx7 condition.
For IPx8, IEC 60529 requires conditions more severe than IPx7 and then leaves the depth and the duration to be agreed between the manufacturer and the user. The supplier declares what was tested.
So IP68 on its own is not a comparable specification. One supplier's IP68 may be one and a half metres for thirty minutes and another's may be three metres for twenty-four hours, and the datasheet line is identical in both cases. Ask what depth and what duration the report states, and you turn one useless line into a real number.
What IP68 is not designed for, at any declared depth, is a directed jet of water.
IP69K: a Pressure Washer, Reproduced in a Laboratory
The IP69K test sprays the product with water at 80 °C, delivered at 80 to 100 bar and 14 to 16 litres per minute, from four angles: 0, 30, 60 and 90 degrees.
Those are the settings of a commercial washdown lance, moved into a laboratory and applied in a controlled sequence. A product that passes can take a daily washdown without its seals opening, which is exactly the duty that kills lamps on machines that are cleaned rather than rinsed.
Why an IP68 Seal Opens Under a Jet
The physics are not subtle. An IP68 seal is holding back hydrostatic pressure, which is the weight of the water sitting above it, spread evenly over the whole gasket.
A pressure washer does something different. It delivers dynamic pressure concentrated on a few square millimetres, and at 80 bar that local force is an order of magnitude beyond anything the same gasket sees under a metre of still water. The jet does not have to beat the seal everywhere. It only has to lift it in one place.
That is why operators of machines with a washdown regime specify the 9K test rather than a depth rating, whether the machine is a harvester, an excavator, a food line or a refuse truck coming back to the depot with organic waste on the rear end.
The implication runs the other way too, and it is the half that usually gets forgotten. Passing the jet test says nothing about sitting under water for an hour. A lamp certified only to IP69K has not been shown to be suitable for a permanently submerged position.
Which Rating Each Duty Needs
| The duty | What the water does to the lamp | Specify | Report to ask for |
|---|---|---|---|
| Agricultural tractors and harvesters, cleaned with a lance | Hot jets at close range, every season, on every position | IP69K | ISO 20653 |
| Construction and earthmoving, washed to shift concrete and clay | Hot jets plus abrasive slurry driven into seal faces | IP69K | ISO 20653 |
| Refuse and municipal bodies, washed at the end of every shift | Daily hot jets, plus leachate standing on the rear end | IP69K | ISO 20653 |
| Food, beverage and hygiene washdown lines | Jets with detergent and sanitiser, several times a day | IP69K | ISO 20653 |
| Marine deck fittings and submerged positions | Standing water, spray, and immersion at depth | IP68, with the declared depth | IEC 60529 |
| Rain, spray and mud, rinsed with a hose only | Running water at low pressure, never a lance | IP67 is usually sufficient | IEC 60529 |
| Underwater and also pressure-washed | Both hazards, in the same week | Both ratings, separately evidenced | ISO 20653 and IEC 60529 |
Products that genuinely carry both ratings exist; four models in our catalogue are specified that way. The thing to check is that they are evidenced separately, because there is no single test that covers both, and a datasheet that lists both without two reports behind it is listing an intention.
What to Ask the Supplier For
A rating is a claim about a test. The claim is worth what the test report behind it is worth, which means a report from an accredited third-party laboratory, naming the laboratory, the conditions and the pass criteria.
For IP67 and IP68 the report to ask for is IEC 60529, and the thing to read on it is the declared immersion depth and duration. For the 9K test the report is to ISO 20653, or to DIN 40050-9 if it predates the changeover. A datasheet line with no report behind it is an unverified claim, whoever printed it.
Our own numbers, so you can see the shape of a real catalogue rather than a marketing one: of the 180 models where we publish an IP figure, 158 are IP69K, 12 are IP67, 4 are IP68, and 4 carry both IP68 and IP69K. The remaining 137 models in the catalogue do not publish one, and for those the honest answer to an IP question is to ask us for the specific model rather than to read a range figure across it. Test reports for the rated models are available on request, and the heavy-duty work lights are where most of the IP69K models sit.
Sealing Is One Failure Mode, Not the Whole Lamp
An IP rating answers one question: did water get in during a defined test. It does not answer how long the lamp lasts, and buyers who over-index on the IP number tend to under-specify the two things that fail more often.
The first is mechanical. Brackets, solder joints and driver components fail under broadband random vibration long before a seal does, which is why a vibration rating matched to the mounting position belongs on the purchase order next to the IP figure.
The second is chemical. Sealing keeps water out of the housing; it does nothing about what salt does to the outside of it, and coastal fleets lose lamps to corrosion at the fasteners and the housing face rather than to ingress. That is a separate specification with separate evidence, covered in our note on IP ratings and saltwater.
Frequently Asked Questions
Is IP69K always better than IP68?
No, because the two are not measuring the same thing. IP69K is better against jets and IP68 is better against depth, and a lamp rated only for one has no evidence for the other. For most industrial machinery IP69K is the more useful of the two, because machines are cleaned far more often than they are submerged, but a permanently submerged fitting needs the depth rating and a jet rating will not substitute for it.
Why do some datasheets write IP6K9K instead of IP69K?
Because that is the notation ISO 20653 uses. The standard puts a K suffix on both digits, so the rating appears there as IP6K9K, while the market and most catalogues shorten it to IP69K. They refer to the same test, and both spellings appear in our own catalogue. It is not a typographical error, and seeing it is a mild signal that whoever wrote the datasheet has read the standard.
Can one light be rated both IP68 and IP69K?
Yes, and four models in our catalogue are. There is no single test that awards both, so a genuine dual rating means the product went through two test programmes and there should be two reports. Ask for both. A datasheet that lists both ratings and produces one report has evidenced one of them.
Does a higher IP rating mean the light lasts longer?
Not by itself. An IP rating describes one failure mode under one defined test, and it says nothing about lumen maintenance, thermal design, vibration endurance or corrosion resistance. A well-sealed lamp with a poor heat path will fade on schedule and still pass its ingress test on the day it is replaced.
Specify With Confidence
One question settles the choice, and it is not about depth. Will this equipment ever meet a pressure washer? If the answer is yes, then IP68 is not enough however many metres the datasheet claims, and the report you want is to ISO 20653.
If the answer is no, and the lamp goes somewhere that is rinsed rather than lanced, an honest IP67 with a report behind it will outlast an IP69K claim with nothing behind it.
