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1、Subject 1026 (In reply, refer to Subject 1026) 12 Laboratory Drive Research Triangle Park, NC 27709 October 27, 2004 TO: Standards Technical Panel (STP) for Household Cooking Appliances (STP 1026); Subscribers to ULs Standards Service for Other Interested Parties Electric Household Cooking and Food
2、Serving Appliances; UL 1026, SUBJECT: Request for Comments on Proposed Requirements for the Fourth Edition of the Standard for Electric Household Cooking and Food Serving Appliances; UL 1026; PROPOSED EFFECTIVE DATE INSTRUCTIONS STP Members: If you are a voting member of the STP, complete the attach
3、ed ballot with your vote on the proposal. Please note that all negative ballots must be accompanied by supporting written reasons and, where possible, proposals for a solution to the problem raised. Impact statements and effective date information are not subject to letter ballot. Therefore, comment
4、s regarding impact statements and effective dates may be made and should be sent to the STP Project Manager separate from the letter ballot. Subscribers and other interested parties: If you are a subscriber or other interested party, you are requested to send comments on the proposed requirements, i
5、mpact statements, and proposed effective dates to the STP Project Manager. The STP member ballot should not be used to submit your comments. Comments should be made in writing and may be sent by fax to (919) 316-5614 or by mail to the attention of Amy Stone at ULs Research Triangle Park office. Comm
6、ents may also be sent via E-mail to Amy.S. Please reference all correspondence to Subject 1026. Note all comments received are public and may be circulated to others. If you respond by fax or E-mail, please include your full name and company name and address to ensure a reply. SUMMARY OF TOPICS This
7、 bulletin proposes a handle strength test. STP BALLOTS AND ALL COMMENTS DUE: DECEMBER I, 2004 Attached as Appendix A is the Rationale statement and description of the change made to the standard. Attached as Appendix B for your review and comment are the impact statements and proposed effective date
8、s. Attached as Appendices C and D, are the STP instructions and ballot. Questions regarding interpretation of requirements should be directed to the responsible UL Staff. SUBJECT 1026 -2- OCTOBER 27,2004 Please note that proposed requirements are of a tentative and early nature and are for review an
9、d comment only. Current requirements are to be used to judge a product until these requirements are published in final form. PRODUCTSANDINDUSTRIESAFFECTED BYTHE PROPOSAL UL requests your assistance in identifying other products or industries that might be affected by the requirements contained in th
10、is bulletin. UL suggests that all suppliers or customers for these products and industries be made aware of these requirements prior to their proposed effective date. Also, please forward your suggestions to UL so that these products and industries may be identified in future bu I let ins. Unless sp
11、ecifically requested to do so, UL will not acknowledge comments indicating concurrence with these proposals. UNDERWRITERS LABORATORIES INC. REVIEWED BY: AMY STONE JOE MUSS0 Project Manager for STP 1026 Standards Department Global Standards RESEARCH TRIANGLE PARK DIVISION Phone: (919) 549-0948 Fax: (
12、919) 316-5614 Email: Joseph.R.M E-mail: Amy.S http:/ Chair for STP 1026 NORTHBROOK DIVISION Phone: (847) 664-2964 Copyright O 2004 Underwriters Laboratories Inc. SR:JAH bl-I 026.420041015 SUBJECT 1026 -Al- OCTOBER 27,2004 APPENDIX A PROPOSED REQUIREMENTS FOR THE FOURTH EDITION OF THE STANDARD FOR EL
13、ECTRIC HOUSEHOLD COOKING AND FOOD SERVING APPLIANCES; UL 1026 For your convenience in review, proposed additions to existing requirements are shown underlined and proposed deletions are shown +me - 2. Insulatina bus hinas; - 3. Liauid-tiaht flexible cord fittinas; 0 Mesh arbs; - 5. Strain relief arb
14、s; 6 Strain relief arbs for bus d rot) cab les; - 7. Strain relief arbs for flexible cords: and - 8. Strain relief with wire mesh cord arbs. 2. MATERIALS RATIONALE UL proposes to reorganize the format of Section 5 by adding subsections for requirements for flammability, temperature ratings, material
15、s substitution, and molding considerations. The intent of the proposal is to provide clarity to the current material requirements in UL 635. In addition, the proposal would clarify the material substitution requirements as well as the extent to which the materials may or may not be modified during t
16、he molding process. The proposed revision of Section 5 includes the following changes: 1. Paragraphs 5.1, 5.3, and 5.4 have been re-designated as Paragraphs 5.1.1, 5.1.2, and 5.1.3 respectively. The proposed Paragraphs 5.1 .I, 5.1.2, and 5.1.3 have been transferred to the proposed Subsection 5.1, ti
17、tled “General.” 2. Paragraph 5.2 has been revised to include a reference to the IEC Standard for Test Flames - 50 W Horizontal and Vertical Flame Test Methods, 60695-11-10. Paragraph 5.2 has been re-designated as Paragraph 5.2.2 and has been transferred to the proposed Subsection 5.2, titled “Flamma
18、bility.” 3. The proposed temperature rating requirements would appear in UL 635 as Subsection 5.3; the proposed requirements for materials substitution would appear in the standard as Subsection 5.4, and the proposed requirements for molding considerations would appear in the standard as Subsection
19、5.5. The proposed requirements in Paragraph 5.2.1 and Subsections 5.3 - 5.5 are based on requirements from the Standard for Positioning Devices, UL 1565. UL determined that Standard UL 1565 was the most appropriate source for the proposed requirements because, like bushings, positioning devices are
20、typically made from similar polymeric materials that are mechanically relied upon to maintain the relative position of insulated wires. PROPOSAL (CURRENT VERSION OF SECTION 5) SUBJECT 635 -A3- SEPTEMBER 27,2004 5 Materials 5.1 Ceramic materials and some molded compositions such as phenolic and urea
21、formaldehyde are capable of being used as materials for a separate insulating bushing. Vulcanized fiber is not prohibited from being used when the bushing is not less than 3/64 inch (1.2 mm) thick, and when it is formed and secured in place so that it is not adversely affected by conditions of typic
22、al moisture. Other materials, such as nylon, are capable of being used after a suitable investigation. See Humidity Test, Section 11, and Elevated Temperature Test, Section 12. 5.2 Materials employed in the construction of insulating bushings shall be classified with a flammability rating of at leas
23、t 94 HB as determined by the Standard for Safety for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances, UL 94. 5.3 Wood, hot-molded shellac, tar compositions, or rubber are not to be used as materials for a separate insulating bushing. 5.4 The wall thickness of an insul
24、ating bushing shall not be less than 3/64 inch (1.2 mm) unless a thickness has been determined to be capable of being used as a result of an investigation (see reference to vulcanized fiber in 5.1). This requirement does not preclude the use of narrow slots or openings in the wall of an insulating b
25、ushing when the intended cable, flexible cord, or insulated wire is not capable of being pressed into such slots or openings. (PROPOSED VERSION OF SECTION 5) 5 Materials 5.1 General 5.1.1 Ceramic materials and some molded compositions such as phenolic and urea formaldehyde are capable of being used
26、as materials for a separate insulating bushing. Vulcanized fiber is not prohibited from being used when the bushing is not less than 3/64 inch (1.2 mm) thick, and when it is formed and secured in place so that it is not adversely affected by conditions of typical moisture. Other materials, such as n
27、ylon, are capable of being used after a suitable investigation. See Humidity Test, Section 11, and Elevated Temperature Test, Section 12. 5.1.2 Wood, hot-molded shellac, tar compositions, or rubber shall not to be used as materials for a separate insulating bushing. 5.1.3 The wall thickness of an in
28、sulating bushing shall not be less than 3/64 inch (1.2 mm) unless a thickness has been determined to be capable of being used as a result of an investigation. See reference to vulcanized fiber in 5.1 .I. This requirement does not preclude the use of narrow slots or openings in the wall of an insulat
29、ing bushing when the intended cable, flexible cord, or insulated wire is not capable of being pressed into such slots or openings. SUBJECT 635 -A4- SEPTEMBER 27,2004 5.2 Flammability 5.2.1 Materials employed in the construction of insulating bushings shall be classified with a flammability rating of
30、 at least HB as determined by the Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances, UL 94 or IEC 60695-1 1-10, Test Flames - 50 W Horizontal and Vertical Flame Test Methods. 5.3 Temperature Rating 5.3.1 The temperature rating of the device, as indicated in
31、 10.1, 12.3, and 15.4, is to be based on the mechanical-without-impact relative thermal index (RTI - Strength) of the material used in the device. The relative thermal index shall be determined in accordance with the Standard for Polymeric Materials - Long Term Property Evaluations, UL 746B. Note: T
32、he relative thermal index of a material is an indication of the materials ability to retain a particular property (such as physical or electrical) when exposed to an elevated temperature for an extended period of time. For each material, a number of relative thermal indices are established, each rel
33、ated to a specific property, and specific thickness of the material. 5.3.2 The temperature rating of a polymeric device shall not exceed the relative thermal index of the material that is selected for the device, in the devices minimum critical thickness. 5.4 Substitution of Materials 5.4.1 Another
34、polymeric material shall be allowed to be substituted in a device having met the requirements of this Standard only when all of the following conditions are met and compliance is determined through appropriate investigation: a) There is an identical generic description (for example: Type 66, 30 perc
35、ent glass filled, FR type, polyamide). b) Tensile strength of materials, determined in accordance with the Standard for Polymeric Materials - Short Term Property Evaluations, UL 746A or IS0 527-1, Plastics - Determination of Tensile Properties - Part 1 : General Principles, and IS0 527-2, Plastics -
36、 Determination of Tensile Properties - Part 2: Test Conditions for Moulding and Extrusion Plastics, shall be compared, and shall indicate that the substitute material has a strength of at least 95 percent of that of the original material. The tensile strengths used in this comparison shall be genera
37、ted by either: 1) A previous investigation or 2) Side-by-side testing of both materials. c) The materials relative thermal indices shall be used for the temperature rating of the device as specified in 5.3.1. SUBJECT 635 -A5- SEPTEMBER 27,2004 5.5 Molding Considerations 5.5.1 Except as indicated in
38、(a) and (b), polymeric materials used to mold or fabricate devices covered by this Standard shall be made from materials that are 100 percent virgin and unmodified by the molder: a) Devices made from thermoplastic materials are limited to 25 percent regrind by weight of the same material, unless the
39、 results of a separate investigation indicate acceptable performance for the material or the specific device. The Standard for Polymeric Materials - Fabricated Parts, UL 746D, includes guidelines to be considered in such a separate investigation. b) Devices covered by this Standard shall be allowed
40、to employ colorants, flame retardants, fillers, mold-release lubricants, color concentrates, dyestuff, chemical blowing agents or reinforcements in conjunction with the polymeric material, when the additive or concentrate is tested and found not to adversely affect the critical properties of the mat
41、erial. An additive or concentrate of unknown performance shall not be used. The Standard for Polymeric Materials - Fabricated Parts, UL 746D, provides guidance for the use of specific additives that may be used in the molding process without need for separate investigation. 5.5.2 Devices shall not e
42、mploy materials that have been blended together unless one of the following conditions have been met: a) When two materials have already been individually considered acceptable for an application, and are both found to be generically similar, are both produced by the same manufacturer, and are both
43、designated HB in the minimum part thickness when tested in accordance with the Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances, UL 94 or IEC 60695-11-10, Test Flames - 50 W Horizontal and Vertical Flame Test Methods, these materials may be dry blended in
44、any proportion by the manufacturer without further testing. b) When two materials have already been individually considered acceptable for an application and are both found to be generically similar, are both produced by the same manufacturer, each is designated V-O, V-I, or V-2 in the minimum part
45、thickness when tested in accordance with the Standard for Tests for Flammability of Plastic Materials for Parts in Devices and Appliances, UL 94 or IEC 60695-11-10, Test Flames - 50 W Horizontal and Vertical Flame Test Methods, and when the results of a separate investigation indicate performance me
46、eting the requirements for the material or the specific device, these materials may be dry blended in any proportion by the manufacturer without further testing. The Standard for Polymeric Materials - Fabricated Parts, UL 746D, includes guidelines for a separate investigation. A device made from ble
47、nded material described in (a) or (b) shall be considered to have flammability, mechanical, and thermal properties that are no better than the performance of the weaker of the individual constituents on a property-to-property basis. 3. STRAIN RELIEF RATIONALE UL proposes to revise Paragraph 10.1 by
48、indicating that samples of a strain-relief bushing are to be conditioned in an oven set at the rated temperature of the bushing for one hour. After the conditioning, the samples are to be subjected to the strain-relief test described in the requirement. SUBJECT 635 -A6- SEPTEMBER 27,2004 The proposa
49、l represents a clarification of how long it is typically required to condition the sample to assure they are being tested at rated temperature. The proposal reflects ULs current (and historical) method of conducting the test described in Paragraph 10.1. UL concluded that the proposed requirement was inadvertently omitted from Paragraph 10.1. PROPOSAL 10.1 Six samples of a strain-relief bushing are to be assembled and placed in an oven that has been preset at rated temDerature of the bushina. After one hour the bushinas