Standard Ratings For Ingress By Foreign Objects And Dust

What Is IP Testing?

Ingress Protection testing, or IP testing, tests a product's ability to protect against “ingress” that is, the infiltration of water, dust and foreign objects. Some of the standards related to IP testing are MIL-STD-810 (Military), RTCA/DO-160 (Radio Technical Commission for Aeronautics), and IEC 60529 (International Electrotechnical Commission).

Many products require insulation from outside elements in order to function properly. Sand is one of these external elements. Ingress protection testing helps determine whether a particular product is going to function appropriately when placed in the field.

What Products Need Ingress Protection?

In America and Canada, many products that are governed by engineering standards such as UL or CSA standards must indicate an ingress protection (or IP) rating. These products include computers, laboratory equipment, certain medical devices, light fixtures as well as products that must remain dust-free or moisture-resistant. Items that are sealed and will likely be placed in hazardous places also need IP ratings.

In certain cases, IP testing is voluntary, but sellers often ask manufacturers for an IP rating before placing a product in inventory. 

Other common items that require ingress protection testing include electrical sockets, cell phones, refrigerators (particularly their electric motors) and wrist watches.

What Are the Ingress Protection Ratings?

Ingress protection ratings are standardized ratings that are used to describe the type and degree of ingress protection that a particular item possesses. The ratings come in two sets: One is for foreign objects and dust (that is, solid bodies), and the other is for liquids (such as water).

Each rating starts with “IP” which stands for ingress protection. The first number after “IP” pertains to the rating against ingress by foreign objects and dust. The second number refers to protection against ingress by liquids. When addressing either one of these two types of contaminants, the remaining type is identified with an X. 

Here are the standard ratings for ingress by foreign objects and dust how to interpret them:

IP0X: This rating indicates the item is not protected at all against ingress from foreign objects.

IP1X: This rating stipulates the item is protected against access from the back of a hand and solid foreign objects that are greater than 50 mm (about 2 inches). This is substantiated by ensuring a 50 mm probe has adequate clearance from hazardous parts and doesn't fully penetrate the item.

IP2X: This rating indicates that any hazardous parts cannot be accessed by a finger or solid objects greater than 12.5 mm (about half an inch). This is tested using a “jointed finger” that is 12 mm to 80 mm long.

IP3X: This rating is given for items in which hazardous parts cannot be accessed using a tool, such as a screwdriver, or by solid foreign objects greater than 2.5 mm (about one-tenth of an inch). This is verified using a 2.5 mm access probe, which cannot penetrate the item.

IP4X: This rating applies to items in which hazardous parts cannot be accessed even with a wire, or foreign objects greater than 1.0 mm. This is tested using a 1.0 mm access probe and by inspection to ensure any dust that enters would not interfere with the part's functionality.

IP5X: This rating applies to hazardous parts that can't be accessed, even with a wire, and protection against ingress from dust is also applicable. This is tested using a 1.0 mm access probe and by inspection to ensure any dust that enters would not interfere with the part's functionality.

IP6X: There can be no ingress of dust at all for this rating. Otherwise, it is similar to IP5X with the exception that the item is completely sealed off from dust.

Testing is verified in each case by a testing engineer, whose job it is to inspect the tested item immediately after the test is completed to determine the result. It's very important that the test engineer be well-trained and knowledgeable in conducting the test and reporting the results.