During lighting design and luminaire selection, we frequently encounter markings such as ‘IP65’, ‘IP44’, “IP20”, and ‘IP69K’. These seemingly simple letters and numbers are actually critical parameters determining whether a luminaire can survive harsh environments. This article provides a comprehensive overview of IP ratings—covering their definitions, assessment criteria, protective relationships, typical applications, and the most stringent rating: IP69K. It empowers you to make more professional selection decisions within the lighting industry.

Ingress Protection Rating (IP rating), defined by the International Electrotechnical Commission standard IEC 60529, measures the degree of protection provided by an equipment enclosure against the ingress of solid objects (such as dust) and liquids (water).

IPXY

• X (first digit) denotes the dust protection rating, ranging from 0 to 6;
• Y (second digit) denotes the water protection rating, ranging from 0 to 9K

For example, ‘IP65’ denotes:

• 6: Complete protection against dust ingress;
• 5: Protection against low-pressure water jets from any direction.

✅ Dual-dimension combination: dustproof + waterproof

The IP rating comprises two independent dimensions:

• A product may be dustproof but not waterproof (e.g. IP60);
• It may also be waterproof but not fully dustproof (e.g. IPX5);
• The optimal state is strong performance in both areas (e.g. IP66, IP69K).

📶 Each digit has its own ‘incremental level’

1st: Dust protection rating (0–6)

2nd: Water resistance rating (0–9K)

👉 Note: Water resistance ratings are not linear but are based on tests simulating different ‘water contact scenarios’.

IP ratings do not represent a linear progression such as ‘from IP20 to IP69K’, but rather a two-dimensional combination matrix. As illustrated below:

📌 Each combination suits different scenarios; there is no absolute hierarchy of superiority or inferiority. The key lies in matching the application context.

❗ IP68 ≠ IP69K!

• IP68 is designed for prolonged underwater immersion;
• IP69K is engineered to withstand high-pressure, high-temperature water jets;
• The testing methods and applicable scenarios for both are entirely distinct and cannot be substituted for one another!

1) What is IP69K?

IP69K represents one of the highest IP protection ratings currently available, combining standards IEC 60529 and DIN 40050-9. It is primarily used for testing equipment in high-temperature, high-pressure water-jetting environments.

• 6: Complete protection against dust ingress;
• 9K: Withstands water jets at 80°C and 100 bar pressure from multiple angles.

2）Test conditions:

• Water temperature: 80 ± 5°C
• Water pressure: 80–100 bar
• Spray angle: 0°, 30°, 60°, 90° (30 seconds each)
• Distance: 100–150 mm, luminaire must rotate to expose all angles

3） Application Scenarios:

⚠️ Important reminder: IP69K protection against high-pressure water jets does not equate to suitability for prolonged underwater immersion. For underwater lighting applications, please use IP68-rated fixtures.

🚫 Common misconceptions:

• Misconception 1: Is a higher IP rating always better?

→ In practice, selection should be based on intended use. Excessively high ratings increase structural complexity and thermal management challenges, leading to higher costs.

• Misconception 2: Does IP68 protect against high-pressure water jets?

→ IP68 refers to immersion testing and cannot substitute for IP69K high-pressure wash certification.

• Misconception 3: Focusing solely on IP ratings while neglecting other performance aspects?

→ Lighting applications must also consider IK impact resistance ratings, corrosion resistance, explosion-proof certification, and other critical factors.

✅ Selection Recommendations:

• Identify environmental risks (dust, moisture, cleaning frequency)
• Review product certifications/reports (verify genuine IP testing compliance)
• Consider luminaire materials, structure, and maintenance complexity holistically

IP ratings are not about ‘the higher the better’, but rather about striking the right balance. Blindly pursuing higher ratings not only increases costs, but can sometimes reduce heat dissipation efficiency and add structural burden.