Protecting sensitive electronics from harsh environmental factors is essential when investing in industrial instrumentation. Whether sensors are in food processing areas facing high-temperature washdowns or outdoor junction boxes enduring heavy rain, even a minor breach can cause safety hazards, expensive downtime, and total equipment failure.
To evaluate this protection, the industry relies on the Ingress Protection (IP) rating. This guide provides a detailed breakdown of the IP rating chart, a comparison of IP67 vs. IP68, and a reliable selection process for your instrumentation.
Defining the IP Rating
An IP Rating (International Protection or Ingress Protection rating) measures how effectively an electrical enclosure blocks liquids, moisture, and foreign objects like dust.
This system is governed by the international IEC 60529 standard, offering facility managers and engineers precise specifications instead of ambiguous terms such as “dust-resistant” or “waterproof”. While IP ratings focus solely on water and dust ingress, NEMA ratings used in North America also consider factors like ice formation and corrosion resistance.
The IP Rating Chart Explained
An IP code consists of the letters “IP” followed by two distinct digits. The higher the number, the greater the level of protection. If a device has an “X” instead of a number (e.g., IPX6), it simply means no data is available for that specific criterion; it does not mean the device is unprotected.
First Digit: Solid Particle Protection
This digit measures the enclosure’s defense against solid objects, ranging from large body parts down to microscopic dust.
| Digit | Level of Protection | Effective Against / Description |
|---|---|---|
| 0 | No protection | No protection against contact and the ingress of objects |
| 1 | > 50 mm | Any large surface of the body, such as the back of a hand, but no protection against deliberate contact |
| 2 | > 12.5 mm | Fingers or similar objects |
| 3 | > 2.5 mm | Tools, thick wires, etc. |
| 4 | > 1 mm | Most wires, slender screws, large ants, etc |
| 5 | Dust protected | Ingress of dust is not entirely prevented, but it cannot enter in sufficient quantities to interfere with the safe operation of the equipment |
| 6 | Dust-tight | Complete protection against contact and no ingress of dust whatsoever. A vacuum must be applied during testing |
Second Digit: Liquid Ingress Protection
This digit indicates the enclosure’s ability to protect internal components against moisture, ranging from light condensation to high-pressure submersion.
| Digit | Level of Protection | Description |
|---|---|---|
| 0 | None | No protection against the ingress of water |
| 1 | Dripping water | Vertically falling drops of water (e.g., condensation) shall have no harmful effect |
| 2 | Dripping water (15° tilt) | Vertically dripping water shall have no harmful effect when the enclosure is tilted at an angle of up to 15° |
| 3 | Spraying water | Water falling as a spray at any angle up to 60° from the vertical shall have no harmful effect |
| 4 | Splashing water | Water splashing against the enclosure from any direction shall have no harmful effect |
| 5 | Water jets | Water projected by a 6.3 mm nozzle against the enclosure from any direction shall have no harmful effects |
| 6 | Powerful water jets | Water projected in powerful jets by a 12.5 mm nozzle against the enclosure from any direction shall have no harmful effects |
| 6K | Powerful water jets (high pressure) | Water projected in powerful jets (6.3 mm nozzle) under elevated pressure (1,000 kPa) shall have no harmful effects |
| 7 | Temporary immersion | Ingress of water in harmful quantities shall not be possible when immersed up to 1 meter in depth for 30 minutes |
| 8 | Continuous immersion | Suitable for continuous immersion in water beyond 1 meter. The exact depth and duration conditions must be specified by the manufacturer |
| 9/9K | High-temperature / High-pressure washdown | Protected against close-range, high-pressure (8–10 MPa / 80-100 bar), and high-temperature (80 °C / 176 °F) water spray downs |
The Role of IP Ratings in Instrumentation
An appropriate IP rating acts as the first line of defense for the precision and longevity of your instrumentation.
- Preventing Signal Malfunction: The ingress of liquids and dust can easily short-circuit electronic equipment or trap heat, providing unintended conductive pathways that cause instruments to malfunction.
- Condensation and Pressure Management: Outdoor junction boxes are heavily prone to condensation due to temperature swings. Utilising an IP67 or IP68 rated box combined with IP-rated breather vents allows pressure to equalise and moisture to escape passively without compromising the enclosure’s waterproof integrity.
- Explosive Atmospheres & Intrinsically Safe (IS) Circuits: In hazardous areas where Intrinsic Safety (Ex i) is deployed, enclosures generally require a minimum rating of IP20. However, if the environment mandates it (e.g., outdoor zones or washdown areas), higher IP enclosures (IP54 to IP66) are strictly required to ensure the associated apparatus remains secure.
How to Select the Right IP Rating: A Quick Guide
Selecting the right IP rating for your instrumentation prevents overspending on unnecessary sealing or under-protecting critical assets. Use this framework:
- Assess the Environment: Will the device be indoors, outdoors, or submerged? For basic indoor facilities without moisture, IP20 to IP40 is often sufficient. For outdoor monitoring, IP65 is the typical baseline.
- Evaluate Water Pressure & Depth: If the device will be submerged continuously, mandate IP68. If it will face high-pressure steam cleaning, mandate IP69K.
- Account for Corrosives and Standards: IP ratings evaluate water and dust, but not corrosion. If operating in a marine or chemical environment, ensure your IP-rated enclosure also utilises corrosion-resistant materials, such as 316L Stainless Steel or UV-resistant plastics. For FDA-regulated facilities, ensure the enclosure uses FDA-grade alloys or plastics.
- Check Cable Entries: A system is only as strong as its weakest link. Ensure that all cable glands, seals, and blanking plugs match or exceed the IP rating of the junction box itself. For instance, fitting an IP68 cable gland into a thin-walled enclosure without the proper sealing washer can drastically lower your system’s overall protection level.
Crucial IP Ratings in Industrial Instrumentation
When specifying transmitters, flow meters, or junction boxes, engineers typically rely on a few high-level IP ratings. Understanding the nuances between them is critical for maximizing ROI. Here are some of the common IP ratings used in industrial instrumentation
- IP54: Standard for General Indoor Use
For indoor industrial gear not exposed to high-pressure cleaning, this rating serves as the primary benchmark.
Capabilities: Guards against water splashes from any angle and restricts harmful dust accumulation.
Common Applications: Lab instruments, internal control panels, and portable testing equipment.
- IP65 & IP66: Weatherproof Outdoor Standards
These ubiquitous ratings characterize instrumentation designed for outdoor exposure, such as transmitters mounted on external piping.
IP65: Provides a dust-tight seal and resists low-pressure water streams.
IP66: Dust-tight construction that withstands powerful jets or heavy sea conditions.
Common Applications: Field junction boxes, temperature probe housings, and pressure transmitters.
- IP67 & IP68: Submersible Equipment Ratings
Essential for hardware in flood-prone zones, sumps, or pits, these ratings ensure functionality under water.
IP67: Supports immersion for 30 minutes at depths up to 1 meter.
IP68: Designed for prolonged submersion based on vendor-defined limits, typically exceeding IP67 requirements.
Common Applications: Subterranean flowmeters, water quality sensors, and wastewater level probes.
- IP69K: High-Pressure & Hygienic Standard
Evolving from the German DIN 40050-9, this represents the highest protection tier for rigorous sanitation environments.
Capabilities: Resists close-range, high-temperature (80°C) and high-pressure washdowns.
Common Applications: Pharmaceutical production, chemical processing, and food and beverage facilities utilizing daily steam cleaning.
