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): IPSTStandard Number: UL 763Edition Date: January 31, 2012Edition Number: 4Section / Paragraph Reference: 18A, 33.1, 49A, 58Subject: Filtered Ventilation Open
3、ingsDECISION:(NEW SECTION)18A Air Filters18A.1 A machine incorporating an air filter over ventilation openings shall be evaluated to determine theeffects of a partially or completely blocked air filter. See 33.1.9 and 49A.1.18A.2 Air filters shall not be located within the electrical enclosure of th
4、e machine and shall be locatedsuch that propagation of flame from one area to another or bridging between a possible source of ignitionand other ignitable parts is unlikely.18A.3 An air filter intended to be replaced or cleaned by the user shall be readily visible and replaceablewithout accessibilit
5、y of live parts or mechanical parts that may cause injury to persons. The machine shallbe provided with instructions as specified in 58.1 for replacement or cleaning of the filter.18A.4 An air filter not intended to be replaced or cleaner by the user need not be readily visible oraccessible and the
6、instructions of 58.1 need not be provided if the machine complies with the NormalTemperature Test with the filter completely (100 %) blocked.33.1.9 (NEW) In accordance with 18A.1, a machine incorporating an air filter over ventilation openingsshall be tested under maximum normal load with a clean fi
7、lter in place. The test shall be repeated with theair filter blocked 50 percent. For the blocked condition, the 50 percent blockage is stated as a percentageof the total effective area of the filtered opening and shall be representative of the most severe and likelycondition based upon the ventilati
8、on design. The filter shall be of the type recommended by themanufacturer and installed in accordance with the instructions.Exception: In accordance with 18A.4 and 49A.1, the test may be conducted with a clean filter and withthe air filter completely (100 %) blocked.(NEW SECTION)49A Abnormal Filter
9、Blockage Test49A.1 A machine incorporating an air filter over ventilation openings shall be tested as described inClauses 49A.2 to 49A.5, and there shall be no:a) emission of flame or molten metal;UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM
10、ULb) glowing or flaming of the tissue paper covered supporting surface or the cheeseclothcovering the machine;c) opening of the 3 A fuse between accessible metal parts and ground;d) dielectric breakdown;e) exposure of live parts; orf) exposure of a mechanical parts that could cause injury to persons
11、.Exception: The Abnormal Filter Blockage Test need not be conducted if the machine complies with theNormal Temperature Test with the filter completely (100 %) blocked.49A.2 A machine shall be operated as described in 49A.4 under each of the following conditions, in turn:a) blocked 75%; andb) blocked
12、 100%.49A.3 Each blockage is stated as a percentage of the total effective area of the filtered opening and shallbe representative of the most severe and likely condition based upon the ventilation design.49A.4 The machine shall be installed and operated as described in 33.1 to 33.21, as applicable.
13、 Themachine shall be:a) Connected to a supply circuit as described in 30.1;b) Placed on a white tissue paper covered softwood surface;c) Draped with a double layer of cheesecloth over the whole machine with the cloth within 1/8inch (3.2 mm) of the openings (if any) in the enclosure; andd) Grounded b
14、y means ofa3Anon-time-delay plug fuse connected between exposed metalparts and earth ground.49A.5 Following operation as specified in 49A.4, the machine shall comply with Accessibility of Live Parts,Section 10, and Protection Against Injury to Persons, Sections 19, 20 and 21; and be subjected to the
15、Dielectric Voltage-Withstand Test, Section 34.58 Instructions58.1 In accordance with 18A.3, a machine provided with an air filter intended to be replaced or cleanedshall include instructions indicating how to:a) Determine when the filter needs replacement or cleaning;b) Obtain a proper replacement f
16、ilter; andc) Replace or clean the filter.Exception: The instructions need not be provided if the machine complies with the Normal TemperatureTest with the filter completely (100 %) blocked.STANDARD NUMBER: UL 763 -2-UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHO
17、UT PERMISSION FROM ULRATIONALE FOR DECISION:The use of an air filter over the ventilation openings of a commercial food preparing machine may increasethe temperatures within the appliance during normal operation due to restricted air flow from passingthrough the filter and accumulation of dirt withi
18、n the filter. Therefore, the Normal Temperature Test shallbe conducted with a clean filter and then repeated with the filter 50 % blocked. In addition, an abnormaloperation test shall be conducted with the filter blocked 75 % and 100 % to verify that this does not resultin an increased risk of elect
19、ric shock or fire. This Certification Requirement Decision is intended todocument present practice.Copyright 2012 Underwriters Laboratories Inc.UL, in performing its functions in accordance with its objectives, does not guarantee or warrant thecorrectness of Certification Requirement Decisions it ma
20、y 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 formal interpretations of thestandard under American National Standards In
21、stitute (ANSI) processes. UL shall not be responsible toanyone for the use of or reliance upon 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 Certi
22、fication 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 763 -3-UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION ORDISTRIBUTION WITHOUT PERMISSION FROM ULSTANDARD NUMBER: UL 763 -4-No Text on This Page
