IP67, IP68 and IP69K Explained for Washdown Weighing
IP67 means dust-tight and protected against temporary immersion at 1 m for 30 minutes; IP68 means dust-tight and protected against continuous immersion under stated conditions; IP69K means dust-tight and protected against high-pressure, high-temperature cleaning jets under ISO 20653. The codes are not cumulative, so washdown scales need combined ratings.
IP ratings are the shorthand buyers use to judge whether a scale, indicator or motor will survive washdown. They are precise test codes, not general quality grades, and a higher number does not always include the lower ones. This article explains what IP67, IP68 and IP69K actually test, where the codes come from and what they mean for weighing equipment on a fishing vessel or in a fish plant.
How the IP code works
The IP code in IEC 60529 has two characteristic numerals: the first for protection against solid foreign objects and dust, the second for protection against water. An "X" replaces a numeral that is not specified, as in IPX9. The standard applies to enclosures of electrical equipment rated up to 72.5 kV (IEC 60529, clause 1). The "K" suffix, as in IP69K, is not an IEC code: it comes from ISO 20653 for road vehicles, which uses IEC 60529 codes except for the "K" codes that describe special requirements for road vehicles.
| First numeral | Meaning |
|---|---|
| 5 | Dust-protected: ingress of dust is not totally prevented, but dust must not enter in a quantity that interferes with operation or safety |
| 6 | Dust-tight: no ingress of dust |
Water tests compared: IPX5 to IPX9K
Each second numeral is defined by a specific test. The conditions below are from IEC 60529, clauses 14.2.5-14.2.8, and Amendment 2 (2013), clause 14.2.9.
| Code | Protection against | Test conditions |
|---|---|---|
| IPX5 | Water jets | 6.3 mm nozzle, 12.5 l/min ±5 %, 2.5-3 m distance, 1 min per m² of surface, minimum 3 min |
| IPX6 | Powerful water jets | 12.5 mm nozzle, 100 l/min ±5 %, 2.5-3 m distance, 1 min per m², minimum 3 min |
| IPX7 | Temporary immersion | Lowest point 1 m below the surface for enclosures under 850 mm high (highest point 150 mm below for taller ones), 30 min, water within 5 K of equipment temperature |
| IPX8 | Continuous immersion | Conditions agreed between manufacturer and user, but more severe than IPX7 |
| IPX9 | High-pressure, high-temperature water jets | Fan jet nozzle, 15 ±1 l/min, water 80 ±5 °C, 175 ±25 mm; small enclosures on a turntable at 5 r/min, sprayed at 0°, 30°, 60° and 90° for 30 s each; large enclosures sprayed from all practical directions, 1 min per m², minimum 3 min |
| IPX9K | Water during high-pressure or steam-jet cleaning | Defined in ISO 20653; the 2023 edition extended the IPX9K test conditions and described how the jet's impact force is measured |
So IP67 means dust-tight and able to withstand 30 minutes at 1 m depth. IP68 means dust-tight and able to withstand continuous immersion under conditions that the manufacturer must state. IP69K means dust-tight and resistant to high-pressure, high-temperature cleaning under the ISO 20653 test.
Higher is not always better: the codes are not cumulative
A frequent misunderstanding is that IP69K includes IP67, or that IP68 includes IP66. IEC 60529 states the opposite (clause 6, as amended in 2013):
- an enclosure rated only IPX7 or IPX8 is considered unsuitable for water jets (IPX5 or IPX6) and need not meet those tests unless it is dual-coded;
- an enclosure rated only IPX9 is considered unsuitable for water jets and for immersion, unless it is multiple-coded;
- a multiple code such as IPX5/IPX7/IPX9 or IPX6/IPX7/IPX9 is needed to claim "versatile" use, and single immersion or IPX9 codes are "restricted" to the conditions tested.
For a washdown scale that also stands in water on deck, a combined rating such as IP66/IP67/IP69K tells you far more than a single code. Ask which codes were actually tested, on which part and by whom.
What IP ratings do not cover
An IP rating is a test result for water and dust ingress, and IEC 60529 is explicit about its limits:
- Fresh water only. Tests are carried out with fresh water; protection "may not be satisfactory" if cleaning uses high-pressure, high-temperature water outside the numeral 9 requirements, or solvents (clause 6, Amendment 2). Seawater, detergents and disinfectants are not part of the test.
- No corrosion, condensation or icing. Protection against corrosion, corrosive solvents, moisture produced by condensation, icing, solar radiation and mechanical impacts is left to the product standard (clause 1).
- New condition. The standard assumes materials and workmanship that maintain the protection under normal conditions of use; worn seals, loose cable glands or a missing connector cap are outside the tested condition.
That is why grade of steel, gasket materials and maintenance matter as much as the IP code; see AISI 304 vs 316 vs 316L and preventing corrosion and extending scale life.
What it means in practice for weighing equipment
| Exposure | Rating to look for | Why |
|---|---|---|
| Hose rinsing with a normal deck hose | IPX5 or IPX6 | Matches the jet tests at 12.5 or 100 l/min |
| Standing water, green water on deck, accidental submersion | IPX7 or IPX8 in addition to a jet rating | Immersion codes do not include jet resistance |
| Daily high-pressure hot-water cleaning in a processing area | IPX9 or IPX9K in addition to jet and immersion ratings | Only numeral 9 tests high temperature and pressure |
| Salt spray and chemical cleaning | Any of the above plus suitable materials and seals | IP tests use fresh water and do not assess corrosion |
Four practical points follow from the test conditions:
- Keep your distance. The IPX9 test sprays from 175 mm at 80 °C; holding a lance closer, hotter or longer on one seam exceeds what was tested.
- Glands and connectors are part of the enclosure. Use the correct gland size and seal, fit caps on unused connectors, and route cables so water runs away from entries.
- Protect sensitive installations during cleaning. FAO guidance for fish plants recommends protecting electrical installations against water and chemicals before cleaning starts (FAO Fisheries Technical Paper 444, section 7.2.2).
- Watch for condensation. Moisture produced by condensation is outside the IP test scope, so inspect seals regularly on equipment that moves between cold holds and warm washdown areas.
Cleaning procedures are covered in cleaning and washdown of scales in fish processing.
How WPL approaches this
WPL builds its marine scales for wet decks and daily washdown. The M2 Series has smooth, rounded edges that shed water, the M6 platform scale has a fully sealed construction designed for daily washdown and saltwater exposure, and the R10 WP indicator is a waterproof variant. When comparing equipment, ask for the rating of each part separately, including indicator, load cells, junction box and cable glands, rather than one figure for the whole system. See the hygiene and materials hub for construction principles.
Frequently asked questions
Is IP69K better than IP68?
They test different things. IP68 covers continuous immersion under conditions stated by the manufacturer, while IP69K covers high-pressure, high-temperature water jets during cleaning. IEC 60529 treats an enclosure rated only for numeral 9 as unsuitable for immersion unless it is also tested and coded for it, so look for a combined rating such as IP67/IP69K.
What is the difference between IPX9 and IPX9K?
IPX9 is defined in IEC 60529 Amendment 2 (2013): 80 degrees Celsius water at 15 litres per minute from 175 mm. IPX9K is defined in ISO 20653 for road vehicles and covers water during high-pressure or steam-jet cleaning. Both address hot high-pressure cleaning but come from different standards, so check which test was actually applied and by whom.
Does an IP67 rating mean a scale can be cleaned with a pressure washer?
No. IP67 only tests dust and temporary immersion at 1 metre for 30 minutes. According to IEC 60529 an enclosure coded only IPX7 is considered unsuitable for water jets. For pressure washing, the equipment should also carry a jet rating such as IPX5 or IPX6, and for hot high-pressure cleaning IPX9 or IPX9K.
Does a high IP rating protect against seawater corrosion?
No. IEC 60529 tests are performed with fresh water, and corrosion, condensation and corrosive solvents are explicitly left to product standards. Resistance to salt water depends on materials, such as AISI 316 stainless steel, suitable gasket and cable materials, crevice-free design and regular rinsing with fresh water.
Sources
- IEC 60529:1989+A1:1999+A2:2013 consolidated version (preview: scope and introduction)
- IEC 60529:1989/AMD2:2013 Degrees of protection provided by enclosures (IP Code), Amendment 2 (preview)
- ISO 20653:2023 Road vehicles - Degrees of protection (IP code), 3rd edition (preview)
- FAO Fisheries Technical Paper 444 (2004) Assessment and Management of Seafood Safety and Quality, Chapter 7 Prerequisites to HACCP
Written and reviewed by WPL Industries weighing engineers. Technical and regulatory content is checked against the cited sources. Editorial policy