How Sharp is That Edge?

The importance of design and testing

Seemingly innocuous products can cause debilitating injuries. It is important carefully consider the impact of users encountering sharp edges on your products.

UL 1439 is an attempt to address unintended sharp edges on products. It was first issued in the early 1970s; since then several other, similar standards have been issued by other organizations.

The standard outlines a structured method to test for sharpness, adding that “an edge for an enclosure opening, frame, guard, knob, handle, or the like shall be smooth and rounded so as not to cause a cut type injury when contacted during normal use or user maintenance.” It requires pressing and sliding product edges over specific layers of special adhesive tapes under a controlled contact force. If the layers can be cut by the edge, then it is considered sharp and potentially dangerous.

The article Determining sharpness of sheet metal edges makes the case for improvements in both design and testing of products. We think the article has some good points and is worth reviewing.