UL 250 CRD-2010 UL Standard for Safety Household Refrigerators and Freezers - Section Paragraph Reference Various Subject Motorized Doors and Drawers (Edition 10 November 01 1993).pdf

1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULUNDERWRITERS LABORATORIES INC. CERTIFICATION REQUIREMENT DECISIONThis Certification Requirement Decision is prepared and published by Underwriters Laboratories Inc.(UL). It is normative for the a

2、pplicable UL Product Certification Program(s); however, it is currently notpart of the UL Standard(s) referenced below.Product Category (CCN): SHZZ, SHMRStandard Number: UL 250Edition Date: November 1, 1993Edition Number: 10Section / Paragraph Reference: VariousSubject: Motorized Doors and DrawersDE

3、CISION:Add the following new paragraphs.4.7A Motorized Doors and Drawers4.7A.1 Motorized door and drawer closing mechanisms shall not present a risk of entrapment or a risk ofinjury.4.7A.2 Drawers with motorized closing mechanisms shall have compartments with a minor dimension ofless than 203.2 mm (

4、8 in.) and a volume of less than 0.056 cubic meters (2 cubic feet), with anyarrangement or removal of shelving.4.7A.3 Doors and drawers with motorized opening/closing mechanisms shall be provided withpinch/crush/shear protection. This may consist of:a) A non-contact photoelectric sensor that, when a

5、ctivated, stops the door or drawer frommoving any further in the same direction.b) An edge sensor installed on the edge of the door or drawer that, when activated, stops thedoor or drawer from moving.c) An inherent door or drawer sensor that, when activated, stops the door or drawer frommoving.d) An

6、y other device that provides pinch/crush/shear protection equivalent to (a), (b), or (c).4.7A.4 A motorized door or drawer shall be provided with means to automatically reverse the closingaction upon contacting an obstruction. This means shall actuate when the leading edge of the door ordrawer is wi

7、thin 50.8 mm (2 in.) from the plane surface of any adjacent drawer, door, or fixed member ofthe refrigerator. Upon contact with an obstruction, the drawer shall immediately reverse direction4.7A.5 A motorized door or drawer shall decelerate as it approaches the closed position and shall not becapabl

8、e of applying a force that exceeds 100 N (22.2 lbf).4.7A.6 An electronic control that performs a pinch/crush protection function shall comply with therequirements ina) UL 60730-1A, the Standard for Electrical Controls for Household and Similar Use, Part 1:General Requirements, and the applicable Par

9、t 2, orUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULb) UL 244A, the standard for Solid-State Controls for Appliances, UL 991, the standard forTests for Safety-Related Controls Employing Solid-State Devices, and UL 1998, the standardfor Soft

10、ware in Programmable Components.4.7A.7 If software is relied upon to perform a safety function, it shall be considered Software Class 1 per1998 or software Class B per UL 60730-1A.4.7A.8 Electronic circuits not relying on software as a protective component need not comply with UL 1998or Clause H 11.

11、12 of UL 60730-1A.4.7A.9 The following shall be considered when judging the acceptability of the protective circuit.Application of UL 991 and 1998 Application of UL 60730-1 and Parts 2Conduct a failure-mode and effect analysis (FMEA) for the protective circuits and functions identified in Clause 4.7

12、A.11.During component faults, if a risk is mitigated due to software within a programmable component, the softwarecomponent shall comply with Clause 4.7A.7.A control being inoperative with respect to movement of the door/drawer meets the criteria for mitigating the risk.Assumed temperature ranges ar

13、e as follows:Indoor Use 0.0 2C (32.0 3,6F) and 40.0 2C (104 3.6F)Cycling test duration shall be 14 daysEndurance test duration shall be 100,000 cyclesRadio-frequency electromagnetic field immunity:Immunity to conducted disturbances When applicable test level 3 shall be usedImmunity to radiated elect

14、romagnetic fields field strength of 3 V/m shall be usedFor exposure to humidity, the following conditions shall apply:21.1 26.7C (70 80F) and minimum 85 percent relative humiditySurge immunity test - Test with installation Class 3 used forother than outdoor use protective devices.For the Electrical

15、Fast Transient Burst Test, test level 1 isto be used;Electrical fast transient/burst immunity such that a test level3 shall be used for all equipment other than outdoor useequipment.Electrostatic Discharge Test with a Severity Level of 3having Contact Discharge at 6 kV to accessible metal partsand a

16、ir discharge at 8 kV to accessible parts of insulatingmaterial4.7A.10 In the evaluation of pinch/crush/shear protection circuits, the critical functions of the paragraph4.7A.11 shall be used:a) to conduct an FMEAb) in investigating the performance during the environmental stress tests, andc) during

17、the power cycling tests of UL 991 or UL 60730-1A.4.7A.11 During the testing of paragraph 4.7A.10, if the motor remains operational, the following criticalconditions shall be maintained.a) The pinch (force) protection shall still be operationalb) The automatic reversal shall still be operational.8.31

18、 Motorized door/drawer obstruction testSTANDARD NUMBER: UL 250 -2-UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM UL8.31.1.1 Doors and drawers with a motorized opening/closing mechanism shall not contact an obstructionwith a force exceeding 100

19、N (22.2 lbf) The obstruction is to be the longitudinal edge ofa1in(25.4 mm)diameter cylinder placed across various parts of the door or drawer so that the axis is perpendicular tothe plane of movement of the door or drawer. The test is to be conducted with the door or drawer emptyand with it loaded

20、in accordance with paragraph 8.25. The refrigeration system is to be operational duringthe tests.Note: A momentary impact force is to be disregarded.8.31.1.2 With respect to the test of 8.31.1.1, the test is to be conducted at any potential pinch/crush/shearpoints across the width and height of the

21、door or drawer. This includes any pinch/crush/shear points thatresult from adjacent doors or drawers being opened or closed at the same time.8.31.2 Endurance test8.31.2.1 The pinch/crush/shear mitigation system and associated components shall withstand 30,000cycles of mechanical operation without fa

22、ilure. For this test, the door or drawer is to be cycled repetitivelyas described in 8.31.1.1. The obstruction is to be in the same location for the entire test, and the draweris to be loaded in accordance with paragraph 8.25. This test may be conducted in conjunction with thecycling test of clause

23、8.28.4. In addition, at the end of the endurance test, the obstruction test of 8.31.1.1shall be repeated.8.31.3 Elastomeric material conditioning test8.31.3.1 An elastomeric material used as a functional part of an edge sensor shall function as intendedafter being subjected to the following tests fr

24、om UL 325, the standard for Door, Drapery, Gate, Louver andWindow Operators and Systems:a) Accelerated Aging Test of Gaskets, Section 48, andb) Puncture Resistance Test, Section 51.11.2.X (New) The user instructions for a refrigerator that has a motorized door or drawer shall indicate“CAUTION. Risk

25、of injury. Children should not be allowed to play with the automatically closing door ordrawer”.RATIONALE FOR DECISION:UL 250 does not currently have motorized door/drawer requirements and this proposal is intended toaddress the additional pinch, crush, shear, and entrapment hazards associated with

26、such doors anddrawers. Manually operated drawers, which are currently Listed by UL, were reviewed and it wasdetermined there is a spring action provided to assist with closing. The spring force on these drawers issignificant. In addition, Motor Carrier Vehicle Safety Standard No. 118 “Power-Operated

27、 Window,Partition, and Roof Panel Systems” was reviewed. Clause S5.1 of this standard references a maximumforce of 100N for power operated windows and similar applications.Copyright 2010 Underwriters Laboratories Inc.UL, in performing its functions in accordance with its objectives, does not guarant

28、ee or warrant thecorrectness of Certification Requirement Decisions it may issue or that they will be recognized or adoptedby anyone. Certification Requirement Decisions are the opinion of Underwriters Laboratories Inc. inpractically applying the requirements of the standard. They do not represent f

29、ormal interpretations of thestandard under American National Standards Institute (ANSI) processes. UL shall not be responsible toSTANDARD NUMBER: UL 250 -3-UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULanyone for the use of or reliance upon

30、Certification Requirement Decisions by anyone. UL shall not incurany obligation or liability for damages, including consequential damages, arising out of or in connectionwith the use or reliance upon Certification Requirement Decisions. The electronic version of theCertification Requirement Decision is the current version and previously printed copies may be outdated.This document is published as a service to ULs certification customersSTANDARD NUMBER: UL 250 -4-