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
approximate information.
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 General
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 Apparatus
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.