Introduction to IP68 Testing Standards and Methods

IP68 is recognized as one of the highest dust and water protection ratings in the industry. Below is a detailed explanation of the standards, test items, and methods applied in IP68 testing.

Core Standard: IEC 60529

The testing and definition of IP68 are primarily based on IEC 60529, an international standard published by the International Electrotechnical Commission (IEC). This standard is commonly referRED to as Degrees of Protection Provided by Enclosures (IP Code).

Important Note:

While IEC 60529 serves as a globally accepted benchmark, its specification for the water protection segment of IP68 (the second digit "8") only defines conditions agreed upon by the manufacturer and user without mandating a unified testing method. This implies that the specific technical connotation of "IP68" may vary across different manufacturers.

Therefore, in practical operations, the following derivative standards based on IEC 60529 are usually referenced or directly adopted, as they provide more explicit definitions of testing conditions:

①　China National Standard: GB/T 4208 (equivalent to IEC 60529)

②　European Standard: EN 60529

③　American National Standard: ANSI/IEC 60529

Interpretation of IP Code

First, let us clarify the meaning of each component in "IP68":

①　IP: Abbreviation for International Protection Rating.

②　First Digit "6": Indicates the level of protection against solid foreign objects (including dust).

③　Second Digit "8": Indicates the level of protection against water ingress.

IP68 Test Items and Methods

In accordance with IEC 60529, IP68 testing mainly consists of two core items: dust resistance testing and water resistance testing.

Test Item 1: Dust Resistance Testing (First Digit "6")

Test Requirement: Complete protection against intrusion of foreign objects and dust. The amount of dust entering the enclosure shall not be sufficient to interfere with the normal operation or safety of the equipment, under conditions where the air pressure inside the enclosure is equal to the ambient pressure.

Test Method – Dust Chamber Test:

1. Equipment Preparation: Place the device in a sealed test chamber (dust chamber) filled with talcum powder, a fine powder that simULates natural dust. The density and particle size of the talcum powder must comply with strict specifications.

4. Testing Conditions: Use a vacuum pump or fan to keep the talcum powder suspended in the chamber, creating a dust fog environment. The test duration shall last for 8 hours.

5. Evaluation Criteria: After the test, open the enclosure and inspect for internal talcum powder ingress. Any visible traces of talcum powder will result in a test failure. Additionally, the equipment must maintain normal functionality both during and after the test.

Test Item 2: Water Resistance Testing (Second Digit "8")

As previously noted, the water resistance test conditions for IP68 require negotiation, but the industry has generally adopted the following mainstream testing methods:

Method A: Continuous Immersion Test

This is the most common and intuitive testing method for ip68 certification.

Test Requirement: Submerge the equipment in water at a depth exceeding 1 meter. The specific depth and duration shall be specified by the manufacturer, but must be more stringent than the requirements for IPX7 (1 meter underwater for 30 minutes).

Common Industry Practices:

①　Consumer Electronics (e.g., mobile phones, smartwatches): Typical test conditions are 1.5 meters water depth for 30 minutes. High-end products may require more rigorous parameters, such as 2 meters depth for 60 minutes.

②　Industrial/Auto Equipment: Conditions may be more stringent, such as 3 meters water depth for 60 minutes or even greater depth and duration.

Test Procedure:

2. Secure the device in a dedicated fixture in its normal operating orientation (e.g., screen facing upward).

3. Gradually submerge the device into a water tank until it REACHes the predetermined depth (e.g., 1.5 meters).

4. Maintain the device at the specified depth for the required duration (e.g., 30 minutes).

5. Upon retrieval, immediately inspect the interior of the enclosure for moisture or water droplets. The equipment must retain full functionality.

Method B: Pressurized Immersion Test

This method simulates the equipment's performance under deeper water pressure (e.g., during swimming or diving), making it more scientific and stringent than simple static immersion.

Test Requirement: Apply a static water pressure equivalent to a specific depth to the device using a pressure tank.

Test Procedure:

For reference: A water depth of 1.5 meters corresponds to a pressure of approximately 15 kPa; a depth of 3 meters corresponds to approximately 30 kPa.

1. Place the device inside a sealed pressure tank.

2. Fill the tank with water and apply pressure. The pressure value is calculated using the formula P = ρgh (where ρ = density of water, g = gravitational acceleration, h = target water depth).

3. Maintain the target pressure for the specified duration (e.g., 30 minutes or longer).

4. Release the pressure, retrieve the device, and conduct inspection and functionality testing.

Note: A device that passes a pressurized immersion test (e.g., equivalent to 3 meters water depth) is not guaranteed for long-term use at an actual depth of 3 meters. However, it does demonstrate higher water resistance reliability compared to devices that only pass a 1.5-meter static immersion test.

Summary