Selecting Sensors for Harsh Environments: IP69K and Explosion Protection
Sensors play a central role in industrial applications. They detect conditions, control processes, and provide the foundation for automation and monitoring. In many areas of application, however, standard solutions quickly reach their limits. We explain what matters when selecting sensors for harsh environments and how IP69K and explosion protection are reliably taken into account.
High temperatures, aggressive cleaning methods, dust, moisture, or explosive atmospheres present challenges that must be taken into account when selecting sensors.
Especially in such environments, it is not just the measurement function that determines a sensor’s suitability, but above all its durability. Protection ratings such as IP69K and requirements for explosion protection are absolutely critical safety-related selection criteria.
Table of contents
- IP69K and Explosion Protection: The Most Important Points at a Glance
- When Standard Sensors Are No Longer Sufficient
- IP protection ratings for sensors: Classifying protection classes correctly
- Explosion Protection for Sensors: What Needs to Be Considered?
- Combining IP69K and explosion protection: is that possible?
- What selection criteria are important for sensors in harsh environments?
- Typical sensor types for harsh environments
- Standards and Certificates: More Than Just Mandatory Information
- Common Mistakes in Practice
- Robustness starts with selection
IP69K and Explosion Protection: The Most Important Points at a Glance
- Sensors for harsh environments must do far more than just provide reliable measurement data.
- Protection ratings such as IP69K ensure resistance to high-pressure cleaning. Explosion protection is required to prevent ignition sources in explosive atmospheres.
- Both requirements are safety-critical and must be taken into account as early as the sensor selection phase.
When Standard Sensors Are No Longer Sufficient
In many industrial applications, conditions prevail that go far beyond normal environmental requirements. Sensors may be permanently exposed to mechanical stress, extreme temperature fluctuations, or chemical influences. Regular high-pressure or steam jet cleaning is part of daily operations in industries such as food, pharmaceuticals, or process manufacturing.
Standard sensor technology is usually not designed for such scenarios. Typical weak points include:
- Leaky housings or unsuitable seals
- lack of resistance to cleaning chemicals
- limited temperature ranges
- unprotected electrical connections
The consequences are failures, measurement errors, or increased maintenance costs. A targeted selection of robust sensors is therefore crucial for the reliability of the entire system.
IP protection ratings for sensors: Classifying protection classes correctly
IP protection ratings indicate how well a housing is protected against the ingress of foreign objects and water. They thus provide important guidance when selecting sensors for harsh environments. However, it is crucial to classify the protection ratings correctly and not to overestimate them.
While IP67 or IP68 already offer a high level of protection against dust and temporary or permanent submersion, they do not cover certain stresses. IP69K was developed specifically for applications in which components are regularly cleaned with high pressure and high temperatures. In such cases, water jets with very high pressure and short range impact the housing—a situation that many sensors cannot withstand despite a high IP rating.
The following applies to sensor selection: The protection class must always match the actual application scenario not only during normal operation, but also during cleaning, maintenance, and malfunctions.
Tip: Our magazine article on the topic “Understanding IP Protection Ratings Correctly” provides a detailed overview.
Typical Applications for IP69K Sensors
- Food and beverage industry
- Pharmaceutical production
- Chemical processing plants
- Hygienically sensitive packaging lines
Explosion Protection for Sensors: What Needs to Be Considered?
Special safety requirements apply in areas with explosive atmospheres. The primary focus is on explosion protection, which is intended to prevent the formation of ignition sources. Sensors in such environments must be appropriately certified.
In practice, this means:
- Sensors must be suitable for the respective Ex zone.
- Electrical energy must be limited or encapsulated.
- Enclosures, connections, and electronics are subject to strict specifications.
Good to know: Explosion protection is not a feature that can be retrofitted. It must be an integral part of sensor and system selection from the very beginning. Misinterpretations or incomplete certifications can not only lead to plant shutdowns but also pose a significant safety risk.
Typical Applications for Explosion Protection
- Chemical and petrochemical plants
- Oil and gas industry
- Painting and coating facilities
- Mills, silos, and dust-laden production areas
- Pharmaceutical production
- Wastewater and biogas plants
Definition: IP Protection vs. Explosion Protection
- IP protection ratings indicate which external influences an enclosure can withstand—such as dust, contact, or water. They say nothing about performance in potentially explosive atmospheres.
- Explosion protection (Ex-Schutz) ensures that equipment in explosive atmospheres does not pose an ignition source. It accounts for electrical, thermal, and mechanical risks—regardless of the IP protection rating.
Combining IP69K and explosion protection: is that possible?
In practice, harsh environmental conditions often occur simultaneously. For example, sensors in potentially explosive areas may be subject to high cleaning requirements at the same time. The combination of IP69K and explosion protection is fundamentally possible, but technically challenging.
The challenges include, among other things:
- sealing while maintaining pressure equalization
- selecting suitable housing materials
- the safe design of cables and connections
This means: A combination makes sense wherever potentially explosive areas are regularly cleaned with high pressure or steam, such as in the food, pharmaceutical, or chemical process industries. The selection of suitable sensors is limited—both requirements must therefore be planned together from the outset and clearly certified.
What selection criteria are important for sensors in harsh environments?
When selecting sensors for harsh operating conditions, several criteria should be systematically evaluated:
- IP protection ratings, especially regarding moisture, dust, and cleaning
- Explosion protection and appropriate Ex certification
- Permissible temperature range during continuous operation
- Resistance to media such as oils, greases, or chemicals
- Mechanical robustness against vibration and shock
- Mounting type and installation situation
- Connection and wiring technology
- Maintenance and replacement concepts
Typical sensor types for harsh environments
Not every sensor technology is equally suitable for demanding operating conditions. In practice, certain sensor types have proven particularly effective.
Inductive sensors
Inductive sensors are considered robust and resistant to contamination. They are well-suited for metallic objects and harsh industrial environments.
Frequently used:
- in industrial automation
- in machines and conveyor systems
- in dusty or oil-contaminated production environments
Ultrasonic sensors
Ultrasonic sensors are frequently used when optical methods reach their limits. They are insensitive to dust, steam, or changing light conditions and are therefore well-suited for harsh environments.
Commonly used:
- in containers and silos
- in dusty, steamy, or splash-prone environments
- in process and packaging plants
Pressure and temperature sensors
Pressure- and temperature sensors often need to be in direct contact with the medium. Housing material, seals, and resistance are critical factors.
Frequently used:
- in hydraulic and pneumatic systems
- in the chemical and pharmaceutical industries
- in potentially explosive plant areas
- in process plants and reactors
- in high-temperature or cryogenic areas
Optical sensors
Optical sensors are usually more limited and require a careful assessment of the environmental conditions.
Standards and Certificates: More Than Just Mandatory Information
In harsh environments, relying solely on technical data is not enough. Standards, certificates, and complete documentation are central components of the selection process and subsequent acceptance.
Important factors include:
- clear specifications regarding IP protection classes and testing procedures
- valid Ex certificates for the intended application
- comprehensible data sheets and test reports
- complete declarations of conformity
By the way: These documents are not only relevant for safe operation, but also for audits, acceptance testing, and maintenance.
Common Mistakes in Practice
Despite clear guidelines, similar mistakes occur time and again in practice:
- IP protection ratings are equated with complete tightness.
- Ex approvals are misinterpreted or not fully taken into account.
- Cleaning processes are not incorporated into the planning.
- Connection and plug-in joints are underestimated.
- Sensors are considered in isolation, not as part of the system.
Many of these errors can be avoided if environmental conditions are analyzed early on and incorporated into the selection process.
Robustness starts with selection
Harsh environments place special demands on sensors. IP69K and explosion protection are not minor details, but key design decisions. Those who consider these aspects early on increase operational reliability, reduce maintenance costs, and avoid costly retrofits.
The right technical equipment is also crucial for implementing such applications from suitable sensors and connection technology to complementary accessories. At Bürklin, you’ll find a wide range of products that support the selection and integration of robust sensor solutions for demanding operating conditions.
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