UL 1439:2018 Tests for Sharpness of Edges on Equipment.
1.1 These requirements cover a test procedure to be used to determine the potential personal injury
related to the sharpness of edges that are part of or associated with appliances and equipment.
2 Units of Measurement
2.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory or
3 Undated References
3.1 Any undated reference to a code or standard appearing in the requirements of this standard shall be interpreted as referring to the latest edition of that code or standard.
4.1 An edge of an enclosure opening, frame, guard, knob, handle or the like of an appliance or equipment shall be smooth and rounded so as not to cause a cut-type injury when contacted during normal use or user maintenance.
Exception: A sharp edge that must be exposed to enable the product to perform its intended function need not comply with the requirement in 4.1.
5.1 The test apparatus is to consist of the following:
a) Sharp-Edge Tester — The instrument consists essentially of a handle with a pivoted arm attached. A constant-tension spring secured to the handle is used to apply a steady force to the arm. The arm head is a piece of cylindrical steel, with an outside diameter of 1/2 in (12.7 mm) and a length of 3/4 in (19 mm), located at the end of the adjustable arm. The arm head is to be wrapped with three layers of tape, the two outer layers act as sensing tapes; the inner layer acts as an indicating tape. Alternately, the tapes are to be applied to a removable sleeve or cap that is placed onto the 1/2 in (12.7 mm) steel arm head. The sleeve or cap shall not exceed 5/8 in (15.9 mm) in diameter. See Figure 5.1 or 5.2.
b) Indicating Tape (Inner Layer) — 3/4 in (19.1 mm) wide, adhesive backed, single-adhesive coated, vinyl foam tape, black in color, having the tape properties given in Table 5.1.
c) Sensing Tape No. 2 (Middle Layer) — 3/4 in (19.1 mm) wide, double-adhesive coated, vinyl foam tape, white in color, having the tape properties given in Table 5.1.
d) Sensing Tape No. 1 (Outer Layer) — 3/4 in (19.1 mm) wide, single-adhesive coated skived tetrafluorethylene tape — natural color, having the tape properties given in Table 5.1. The skived tetrafluorethylene backing (film) is shaved in a thin layer from a cylindrical block of material.UL 1439 pdf download.