UL 1439:2011 free download

UL 1439:2011 free download

UL 1439:2011 free download Tests for Sharpness of Edges on Equipment
1 Scope
1.1 These requirements cover a test procedure to be used to determine the potential personal injuryrelated to the sharpness of edges that are part of or associated with appliances and equipment.
1.2 Deleted June 1,2004.
2 Units of Measurement
2.1 Values stated without parentheses are the requirement.Values in parentheses are explanatory orapproximate information.
3 References
3.1 Any undated reference to a code or standard appearing in the requirements of this standard shall beinterpreted 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 equipmentshall be smooth and rounded so as not to cause a cut-type injury when contacted during normal use oruser maintenance.
Exception: A sharp edge that must be exposed to enable the product to perform its intended functionneed 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 thearm.The arm head is a piece of cylindrical steel,with an outside diameter of 1/2 inch (12.7 mm) and a length of 3/4 inch (19 mm), located at the end of the adjustable arm.The arm headis to be wrapped with three layers of tape, the two outer layers act as sensing tapes; the innerlayer acts as an indicating tape. Alternately, the tapes are to be applied to a removable sleeveor cap that is placed onto the 1/2-inch (12.7-mm) steel arm head.The sleeve or cap shall notexceed 5/8 inch (15.9 mm) in diameter. See Figure 5.1 or 5.2.
b) lndicating Tape (Inner Layer)- 3/4-inch (19.1-mm) wide, adhesive backed, single-adhesivecoated, vinyl foam tape, black in color, having the tape properties given in Table 5.1.
c)Sensing Tape No.2(Middle Layer) – 3/4-inch (19.1-mm) wide, double-adhesive coated, vinylfoam tape, white in color, having the tape properties given in Table 5.1.
d) Sensing Tape No. 1(Outer Layer) – 3/4 inch-(19.1-mm) wide, single-adhesive coated skivedtetrafluorethylene tape – natural color, having the tape properties given in Table 5.1.The skivedtetrafluorethylene backing (film) is shaved in a thin layer from a cylindrical block of material.
e) Calibration Equipment – A mass that can exert 1 -1 /2 ±0.03 lbf (6.672 ±0.1 33 N) and a length of string.
6 Calibration of Tester
6.1 The sharp edge tester shall be calibrated so that a 1 -1 /2 ±0.03 lbf (6.672 ±0.1 33 N) is present at the center of the head when the arm is between stops. The length of the arm is to be adjustable for calibration purposes. See Figure 6.1 for a typical calibration procedure.