Marine Equipment Water Ingress Protection Testing and Ratings

By Chuck Thompson: Senior Environmental Engineer at Elite Electronic Engineering 

At Elite, we test electrical and electronic products to ensure they operate reliability in their end use environment. One seemingly simple but important test is water Ingress Protection (IP). Its purpose is to evaluate the ability of an enclosure to prevent water from entering and interacting with any live electrical elements housed within.

While nearly every electrical product will require some type of water IP, for this article we address applications in the Marine industry and how IP is applied for watercraft ranging from commercial cargo ships to recreational boats.

The primary responsibility for water IP starts with the product designer who has the foundational knowledge of the device, its intended application, and knows which materials and processes can be applied to make it suitable for its wet environment while still being manufacturable and affordable.

It is also important to know which standardized tests may be required for the eventual product validation. In the commercial marine industry, many products are subject to type certification by the various International Association of Classification Societies (IACS) marine classification societies. Each has their own testing standard and will prescribe an appropriate IP test to ensure a degree of protection suitable for the application and location onboard the ship or offshore platform. Their standards typically encompass IACS requirements and reference elements from IEC 60945, IEC 60533, or IEC 60092.

IACS Members
Lloyd's Register
Bureau Veritas
Registro Italiano Navale
American Bureau of Shipping
DNV
Nippon Kaiji Kyokai
Polish Register of Shipping
Croatian Register of Shipping
China Classification Society
Korean Register of Shipping
Indian Register of Shipping

In the recreational craft industry, there are generally no agency specified water IP requirements, however boat builders (OEMs) and aftermarket installers have expectations that electronic products used in their boats will operate reliability given the product’s location and application.

Regardless of where the water IP requirements originate, most testing eventually points to the recognized protection standard, IEC 60529. It addresses water exposure, access by solid foreign objects, and dust but because we’re discussing marine applications, our focus on the water ingress testing.

IEC 60529 Water-Ingress Tests and Ratings

IEC 60529 describes a range of standardized water exposure tests that are labeled with designating codes starting at IPX1 and increasing in severity and ending in IPX9. Each is briefly described here:

  • IPx1 Dripping water:

Vertically falling water drops at the rate of 1 mm/minute applied for 10 minutes.

  • IPx2 Dripping water when tilted up to 15°:

Similar to IPx1, but with the enclosure tilted up 15° from its normal position and a rainfall rate of 3mm/minute.

  • IPx3 Spraying water:

Water falling as a spray at any angle up to +/-60° from vertical. This test can be applied using a showerhead that delivers 10 liters/minute for at least 5 minutes.

  • IPx4 Splashing of water:

Similar to IPx3 but more exposure on the test item at up to +/-180° from vertical.

  • IPx5 Water jets:

Water projected by a 6.3 mm nozzle against the product enclosure from any direction. The water jet is 12.5 liters/minute at a distance from 2.5 to 3 meters and for at least 3 minutes.

  • IPx6 Powerful water jets:

Same as IPx5, but 12.5 mm nozzle and 100 liters/minute.

  • IPx7 Immersion up to 1 m:

Immerse product in water 1 meter measured at bottom of the product and at least 15 cm measured at the top of the product for 30 minutes.

  • IPx8 Immersion beyond 1 m:

Same as IPx7 but with the immersion depth and duration defined by the manufacturer.

  • IPx9 High Pressure and Temperature Water Jets:

Fan jet nozzle at 15 liters/minute for 30 seconds per spray position and at least 3 minutes.

Additionally,   

  • When a water IP rating is assessed to a product all lower numbered IP ratings are also met without the product being tested. However, this only applies for drip, spray, and jetting ratings from IPx1-IPx6. This means that some products that require a versatile rating covering immersion or high-pressure water jets will also be separately tested to receive a versatile rating. Examples of versatile ratings include IPx6/IPx7, or IPx5/IPx8, or IPx4/IPx7/IPx9.
  • For some products it is possible to spray a water sensitive colorimetric developer into the enclosure prior to testing. This material may help identify leak paths when water enters the enclosure. It changes color to indicate the presence of a leak and approximately where the leak originated. Whenever possible consider a water indicator prior to product assembly.
  • IEC 60529 requires the product and water temperature be within a 5 K (Kelvin) of each other. This is necessary to prevent a thermal shock stress or any pressure differential. Test items often are conditioned at lab ambient temperatures or in a thermal chamber to align the product temperature with that of the water.

Advice for IEC 60529 Water Ingress Testing

  • When a commercial marine application requires type certification by a IACS marine class society it is important to coordinate testing with the marine surveyor and Elite’s lab scheduler. In particular, be certain to have an approved test plan in place before testing begins. Also, determine if the surveyor will require on-site witnessing or at least witness the posttest evaluation.
  • Establish how the posttest evaluation will be performed.
    •  Will the device be opened and visually examined?
    • Is an operating functional test performed?
    • Who will open the product, Elite or the client personnel?
    • Review how the product can be opened without dripping exterior water into the protected space.
  • State in the test plan if pre-test or post-test dielectric withstand testing or insulation resistance testing is required.
  • Identify if the Elite testing is being performed to support a separate electrical safety assessment conducted by others, for example per IEC 61010 or IEC 62368. In these instances, the post-test evaluation is important and will be specified by the safety testing agency.

Even though water testing may appear to be a simple and straightforward test there still other details of the test to consider, and even more so when the results are for marine applications.

If you have a marine water ingress test requirement or questions on any types of ingress testing, contact us so we can review the details of your product, the validation requirements, and provide advice to help you make your testing successful.

For more information about IP water ingress testing or any other testing services at Elite, contact Chuck Thompson at Elite Electronic Engineering, Inc.

Phone: 630-495-9770