IP protection classes describe the degree of protection of a device against the ingress of dust and water. Another key point is protection against contact and personal injury from electrical voltage. They are particularly important in hydraulics, as components - from sensors and level indicators to measuring devices - are often used in environments with moisture, dirt, mud, oil mist or regular cleaning. A suitable IP protection class guarantees functional safety, health protection extends the service life and ensures reliable machine availability. The abbreviation IP stands for International Protection.
The IP code (IEC 60529) consists of two codes:
First digit: Protection against the ingress of foreign bodies (0-6)
Second digit: Protection against the ingress of water (0-9K)
Example: IP67
"6" = completely dustproof
"7" = Protection against temporary immersion in water
This makes it easy to recognise whether a component is suitable for water jets, moisture, submersion or high-pressure cleaning.
This table shows the IP protection classes relevant to the industry - regardless of whether STAUFF uses them. They describe the protection levels that typically play a role in industry, mechanical engineering, electronics, automotive and hydraulics.
IP protection class | Protection against foreign bodies | Protection against water | Typical areas of application |
IP20 | Finger protection | No water protection | Switch cabinets, electronic housings |
IP40 | Protection from wires/tools | No water protection | Indoors, dry industrial environments |
IP44 | Limited protection against foreign bodies | Splash water | Building technology, machines, installations |
IP54 | Dust protected | Splashproof | Industrial plants, workshops |
IP55 | Dust protected | Jet water | Machines and aggregates |
IP65 | Dustproof | Jet water | Hydraulics, mobile machines, industry |
IP66 | Dustproof | Strong water jets | Outdoor areas, mobile systems |
IP67 | Dustproof | Submersion (temporary) | Hydraulic tanks, sensors, mobile machines |
IP68 | Dustproof | Submersion (permanent) | Offshore, tank interiors, sensor technology |
IP69K | Dustproof | High-pressure/steam jet cleaning | Food, commercial vehicles, construction/agricultural machinery |
Hydraulic systems are typically exposed:
Dust, abrasion, dirt and mud
Oil mist, moisture, rain and condensation
Cleaning with water jets or high pressure
Mechanical loads and vibrations
A suitable protection class minimises the risks of:
Sensor failures
Moisture in electrical contacts
Corrosion and short circuits
unplanned downtimes
STAUFF therefore deliberately specifies IP protection classes in an application-orientated manner in order to guarantee reliability and operational safety.
The optical-electrical level indicator SNKK combines a compact design with a high protection class - ideal for mobile or harsh hydraulic environments.
Technical advantages
Standard: IP69K - suitable for high-pressure/steam jet cleaning
This standard means more precisely: Even if water hits the housing from any direction with greatly increased pressure, this must not have any damaging effect.
40 mm more compact than the standard SNK series
Electrical SPDT switching function
Developed for demanding environments and simple electrical connection despite installation close to the floor
The SPDT switching function makes it possible, for example, to switch from a red to a green signal light to inform the operator of the fill level from a distance.
Practical benefits
Ideal for construction, forestry and agricultural machinery, stationary hydraulic tanks
High resistance to dirt, moisture and vibration
Can be cleaned with a high-pressure cleaner (IP69K)
Market comparison: Comparable level indicators are not only significantly larger, but are also only available up to IP65
STAUFF SNA - Optical level indicators
IP65
For standard applications on hydraulic tanks, protected against dust and water jets.
STAUFF SNK - Optical-electrical level indicators
IP65, optional IP67
For applications with electrical switching signal in environments with moisture.
STAUFF TS-SNA/SNK-PT100 - Temperature sensors
IP68
Suitable for permanently damp or submerged areas.
STAUFF SPG-063 / SPG-100 - Mechanical pressure gauges
IP65 from 16 bar, IP54 below 16 bar
Stainless steel pressure gauges for stationary and mobile hydraulics.
STAUFF SPG-DIGI / SPG-DIGI-USB - Digital pressure gauges
IP65
For precise service measurements on site.
PPC-04-plus - Hydraulic measuring device (analogue)
IP54
Suitable for protected areas of application.
PPC-04-plus-CAN - Hydraulic measuring device
IP67
For mobile applications with moisture and dirt exposure.
PPC-PAD-light / PPC-PAD-light-CAN
IP65
Touch-based measuring devices for industrial and outdoor applications.
PPC-PAD-plus - Multifunctional measuring device
IP65
For complex system diagnostics under industrial conditions.
PT-RF - Wireless Pressure Transmitters
up to IP69/IP69K
For applications with intensive cleaning and harsh environments.
The selection depends on the application environment:
Indoors, low humidity → IP54
Outdoor area, water jets → IP65
Mobile machines, temporary submersion → IP67
High-pressure/vapour jet cleaning → IP69K
Unprotected outdoor area -> IP45
Essential criteria are: Moisture, soiling, cleaning pressure, installation position and mechanical load.
IP protection classes define the degree of protection against dust and water. In hydraulics, they ensure the function of sensors, level indicators and measuring devices in harsh environments.
IP65 protects against water jets, IP67 also protects against temporary immersion. IP67 is usually recommended for mobile applications.
IP69K is relevant if components are regularly cleaned with high-pressure/vapour jets - for example in commercial vehicles or mobile hydraulic units.
Stationary systems → IP65
Mobile machines → IP67
Cleaning with high pressure → IP69K
No, they define water resistance - not absolute watertightness.
IP67 protects against brief immersion
IP69K against intensive high pressure
Examples: SNKK (IP67/IP69K), TS-PT100 (IP68), PT-RF (IP69K).
IP65 and IP67 are considered standard. IP69K is becoming increasingly important for mobile machines.
By analysing humidity, soiling, cleaning methods and installation position. For demanding environments, it is better to choose a higher protection class.
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