Applying the IEC 60529 Ed. 2.2 2013 standard

Given that one of the primary features of our MVP is that the robot is able to traverse and submerge in aqueous environments, waterproofing the electr-mechanical components of our robot is essential. We at HARRT have elected to use the IEC 60529 Ed. 2.2 2013 standard, which dictates the criteria for testing and specifying the Ingress Protection (IP) rating of a given system. We selected this standard due to our widespread familiarity with its applications and due to its widespread use in many commercialized products today. While the IEC 60529 standard only covers ratings for freshwater, we have assumed, for simplicity of development, that our system will be designed for usage in freshwater conditions. Although one of our potential stakeholders include users who operate in marine environments, salinity and complex solution testing requires additional testing that would consume valuable time the team could otherwise spend developing other essential components. We believe that proving the system can be operated in freshwater environments will act as a sufficient baseline and proof-of-concept for future teams, engineers, and researchers to build off of with confidence.

Regarding testing environments and required materials to determine the IP rating of our robot, we have first determined a minimum target of an IP28 rating with an idealized goal of an IP68 rating. 

In the IP rating system, the first digit signifies the level of protection of hazardous components against foreign solid objects. Hazardous components include circuit boards, motors, and other systems essential for the product’s operation. A degree of 2 means that our robot must be protected against fingers and objects as small as 12.5 mm in diameter with applied forces of 30 N ± 10%. We decided this to be our minimum foreign object protection level so as to ensure technicians in the field cannot accidentally injure themselves and to protect the robot from larger rocks, sticks, and other obstructions from impeding its operation. Idealistically, we would work towards a degree of 8, which fully protects the system against dust. This is done via testing the component in an enclosed dust chamber by forcing air mixed with talcum powder through the environment at atmospheric pressure with the goal of drawing a specific volume of air per hour, via depression, through the component’s enclosure. However, given the complexity of constructing a test chamber to meet the requirements of a degree 5 or 6 protection against foreign objects, the team has relegated this to be a design goal later in the project’s development, time permitting. 

The second digit in the IP rating system is used to mark the level of protection against the ingress of water. As the design goal of this robot is to be able to swim fully submerged at depths, the obvious minimum protection level is degree 8. At this specification, the tested components must exceed the tests required for protection degree 7, where the components must withstand total submersion in fresh water at a depth of 1 meter for 30 minutes. At degree 8, the standard’s requirements generalize, stating that the conditions shall be agreed on between the manufacturer and the user but are more severe than degree 7. As such, we at HARRT are continuing our discussion as to what these conditions may include. Current ideation includes operation for an hour at 2 meters depth (depth of an Olympic swimming pool).