1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL 1242 Electrical Intermediate Metal Conduit SteelUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM ULUL COPYRIGHTED MATERIAL NOT AUTHORIZ
2、ED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL Standard for Safety for Electrical Intermediate Metal Conduit Steel, UL 1242 Fourth Edition, Dated February 16, 2006 Summary of Topics 1. Addition of Requirements for IMC Manufactured from Stainless Steel and Removal of Figure
3、 14 and Related References Text that has been changed in any manner or impacted by ULs electronic publishing system is marked with a vertical line in the margin. Changes in requirements are marked with a vertical line in the margin and are followed by an effective date note indicating the date of pu
4、blication or the date on which the changed requirement becomes effective. The revised requirements are substantially in accordance with Proposal(s) on this subject dated January 10, 2014. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted
5、 in any form by any means, electronic, mechanical photocopying, recording, or otherwise without prior permission of UL. UL provides this Standard as is without warranty of any kind, either expressed or implied, including but not limited to, the implied warranties of merchantability or tness for any
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7、 been advised of the possibility of such damage. In no event shall ULs liability for any damage ever exceed the price paid for this Standard, regardless of the form of the claim. Users of the electronic versions of ULs Standards for Safety agree to defend, indemnify, and hold UL harmless from and ag
8、ainst any loss, expense, liability, damage, claim, or judgment (including reasonable attorneys fees) resulting from any error or deviation introduced while purchaser is storing an electronic Standard on the purchasers computer system. The requirements in this Standard are now in effect, except for t
9、hose paragraphs, sections, tables, gures, and/or other elements of the Standard having future effective dates as indicated in the note following the affected item. The prior text for requirements that have been revised and that have a future effective date are located after the Standard, and are pre
10、ceded by a SUPERSEDED REQUIREMENTS notice. MARCH 5, 2014 UL 1242 tr1UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL MARCH 5, 2014 UL 1242 tr2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION
11、 WITHOUT PERMISSION FROM UL FEBRUARY 16, 2006 (Title Page Reprinted: March 5, 2014) 1 UL 1242 Standard for Electrical Intermediate Metal Conduit Steel First Edition October, 1983 Second Edition July, 1996 Third Edition July, 2000 Fourth Edition February 16, 2006 This ANSI/UL Standard for Safety cons
12、ists of the Fourth Edition, including revisions through March 5, 2014. The most recent designation of ANSI/UL 1242 as an American National Standard (ANSI) occurred on March 5, 2014. ANSI approval for a standard does not include the Cover Page, Transmittal Pages, Title Page, or effective date informa
13、tion. The Department of Defense (DoD) has adopted UL 1242 on May 21, 1984. The publication of revised pages or a new edition of this Standard will not invalidate the DoD adoption. Comments or proposals for revisions on any part of the Standard may be submitted to UL at any time. Proposals should be
14、submitted via a Proposal Request in ULs On-Line Collaborative Standards Development System (CSDS) at http:/. ULs Standards for Safety are copyrighted by UL. Neither a printed nor electronic copy of a Standard should be altered in any way. All of ULs Standards and all copyrights, ownerships, and righ
15、ts regarding those Standards shall remain the sole and exclusive property of UL. COPYRIGHT 2014 UNDERWRITERS LABORATORIES INC. ANSI/UL 1242-2014UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL MARCH 5, 2014 ELECTRICAL INTERMEDIATE METAL CONDU
16、IT STEEL - UL 1242 2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL CONTENTS INTRODUCTION 1 Scope .5 2 Units of Measurement .5 3 References .5 4 Glossary .5 CONSTRUCTION 5 General 6 6 Protective Coatings .6 6.1 General .
17、6 6.2 Surface treatments 6A 6.3 Supplementary coatings .7 6.4 Alternate corrosion-resistant coatings .7 7 Threading and Chamfering .7 7.1 General .7 7.2 Protection of threads 8 7.3 Dimensions of threads 8 7.4 Taper of threads .9 8 Thread Gauging 9 9 Straight Conduit .10 10 Nipples 11 11 Elbows 11 12
18、 Couplings 12 PERFORMANCE 13 Identication of Compounds 14 14 Bending .14 14.1 Ambient temperature .14 14.2 Low temperature .15 15 Protective Coatings .15 15.1 Zinc coating .15 15.2 Alternate corrosion-resistant coatings .17 15.3 Organic coatings .20 16 Tensile Strength and Adhesion .21 17 Cold Impac
19、t Test .22 18 Flammability Test .22 18.1 General .22 18.2 Preparations .22 18.3 Conduct of the test .25 19 Beam-Strength .25 20 Threaded-Conduit Pullout 26 MARKINGS 21 Details .27 MARCH 5, 2014 ELECTRICAL INTERMEDIATE METAL CONDUIT STEEL - UL 1242 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER
20、REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL EXAMINATION OF FINISHED PRODUCT BY MANUFACTURER 22 General 28 FEBRUARY 16, 2006 ELECTRICAL INTERMEDIATE METAL CONDUIT STEEL - UL 1242 4UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL IN
21、TRODUCTION 1 Scope 1.1 These requirements cover steel electrical intermediate metal conduit (IMC), nipples, elbows, and couplings. This conduit is provided in trade sizes 1/2 4 (16 103), for use as a metal raceway for the installation of wires and cables in accordance with the National Electrical Co
22、de (NEC), NFPA 70. The values in parentheses are metric designators of conduit. 1.2 Steel intermediate metal conduit is provided both internally and externally with an acceptable level of corrosion resistance in normally corrosive environments. Reference 6.1 for details regarding protective coatings
23、. 1.2 revised March 5, 2014 2 Units of Measurement 2.1 Values stated without parentheses are the requirement. Values in parentheses are explanatory or approximate information. 3 References 3.1 Any undated reference to a code or standard appearing in the requirements of this standard shall be interpr
24、eted as referring to the latest edition of that code or standard. 4 Glossary 4.1 For purposes of this standard the following denitions apply. 4.2 COATING(S), ALTERNATE CORROSION-RESISTANT A coating(s) (other than one consisting solely of zinc) that, upon evaluation, has demonstrated the ability to p
25、rovide the level of corrosion resistance required on the exterior of conduit. Coatings may include zinc. See 15.2. 4.3 COATING(S), ORGANIC A coating(s) (other than one consisting solely of zinc) that, upon evaluation, has demonstrated the ability to provide the level of corrosion resistance necessar
26、y where the coating is not subject to physical damage, such as on the interior of conduit. The coatings may include zinc. See 15.3. 4.4 COATING(S), ZINC A coating consisting solely of zinc, that, upon evaluation, has demonstrated the ability to provide the level of corrosion resistance required for
27、the exterior or interior of the conduit as applicable. See 15.1. MARCH 5, 2014 ELECTRICAL INTERMEDIATE METAL CONDUIT STEEL - UL 1242 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL CONSTRUCTION 5 General 5.1 Each tube shall be constructed o
28、f steel or stainless steel. 5.1 revised March 5, 2014 5.2 Each tube shall have a circular cross section, thereby facilitating the cutting of clean, true threads. All seams shall be thoroughly welded. 5.3 A welded seam shall be without any metal trimming, sharp edge, or sharp projection. A slight bea
29、d on the interior wall at the weld line is not prohibited when the bead is not sharp and when the bead does not decrease the interior diameter of the tube by more than: a) 0.015 inch (0.38 mm) for trade sizes 1/2 2 (16 53) or b) 0.020 inch (0.51 mm) for trade sizes 2-1/2 4 (63 103). 5.4 Before the p
30、rotective coating is applied, the interior and exterior surfaces of each tube shall be free from scale, ash, or any other protrusion. 6 Protective Coatings 6.1 General 6.1.1 The exterior surface of the steel conduit shall be protected against corrosion by a zinc or an alternate corrosion-resistant c
31、oating. 6.1.1 revised March 5, 2014 6.1.2 The interior surface of the steel conduit shall be protected against corrosion by an organic or zinc coating. 6.1.2 revised March 5, 2014 6.1.3 Conduit and ttings constructed of stainless steel are not required to be provided with interior or exterior protec
32、tive coatings. 6.1.3 added March 5, 2014 MARCH 5, 2014 ELECTRICAL INTERMEDIATE METAL CONDUIT STEEL - UL 1242 6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 6.2 Surface treatments 6.2.1 When one or more surface treatments not exceeding 0.00
33、015 inch (0.38 mm) are used as a top coat or conversion coating, the coatings are not required to meet the requirements for an alternate corrosion-resistant or organic coating. MARCH 5, 2014 ELECTRICAL INTERMEDIATE METAL CONDUIT STEEL - UL 1242 6AUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER RE
34、PRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL MARCH 5, 2014 ELECTRICAL INTERMEDIATE METAL CONDUIT STEEL - UL 1242 6B No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 6.3 Supplementary coatings 6.3.1 The use of one
35、or more supplementary coatings is not prohibited. The supplementary coating or coatings are not required to meet the requirements for primary corrosion-resistant coatings. Conduit, elbows, or nipples that are provided with supplementary coatings that have not been evaluated as furnishing corrosion-r
36、esistance for the tube shall be marked in accordance with 21.8. 6.3.2 Supplementary nonmetallic coatings shall be evaluated with respect to ame propagation, any detrimental effects on the corrosion resistance provided by the primary protective coating, the t of couplings, and electrical continuity w
37、ith couplings. The supplementary coating shall be provided in addition to the full primary corrosion-resistant coating. 6.4 Alternate corrosion-resistant coatings 6.4.1 Conduit provided with a nonmetallic alternate corrosion-resistant coating that is not marked with a temperature designation, or is
38、marked 200 F , is for use in ambient temperatures not in excess of 200F (90C). Conduit provided with a nonmetallic alternate corrosion-resistant coating that is for use at temperatures in excess of 200F may be marked with a higher rating that has been evaluated in accordance with Section 15.2. See 2
39、1.6. 6.4.2 Conduit provided with a nonmetallic alternate corrosion-resistant coating that is not marked with a temperature designation, or is marked 32 F , is for use in ambient temperatures not below 32F (0C). Conduit provided with a nonmetallic alternate corrosion-resistant coating that is for use
40、 at temperatures below 32F may be marked with a lower rating that has been evaluated in accordance with 14.2.1 and the Cold Impact Test, Section 17. See 21.7. 7 Threading and Chamfering 7.1 General 7.1.1 Each elbow, nipple, or straight length of conduit shall be threaded on both ends. Each end shall
41、 be chamfered on the interior surface to remove burrs and sharp edges formed by the cutting-off tool. All the effective length of threads (L 2 ) shall be full and clean cut. 7.1.2 Threads that are cut before the pickling operation of the cleaning process are susceptible to being eaten away by the ac
42、id so that very little metal remains, particularly at the crest of the threads. The tube manufacturer is to guard against this condition prior to pickling, after pickling, and before the coating is applied. When found, this condition is to be corrected by recutting the threads, or the tube is to be
43、rejected for conduit purposes. FEBRUARY 16, 2006 ELECTRICAL INTERMEDIATE METAL CONDUIT STEEL - UL 1242 7UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 7.2 Protection of threads 7.2.1 Threads are to be given a protective coating to prevent c
44、orrosion from occurring before installation. The coating is not required to comply with Protective Coatings, Section 6. 7.3 Dimensions of threads 7.3.1 The nished threads provided on conduit, nipples, and elbows shall comply with the dimensions of the NPT (National Pipe Taper) thread outlined in Fig
45、ure 7.1, when measured using the ring gauges described in 8.1. See Table 7.1. This is generated text for gtxt. Table 7.1 Dimensions of threads Trade size (Metric designator) Number of threads per inch L 4 Total length of threads, a L 2 Effective length of threads, Pitch diameter E o at end of condui
46、t, b inches (mm) inches (mm) inches (mm) 1/2 16 14 0.78 19.8 0.53 13.5 0.758 19.3 3/4 21 14 0.79 20.1 0.55 14.0 0.968 24.6 1 27 11-1/2 0.98 24.9 0.68 17.3 1.214 30.8 1-1/4 35 11-1/2 1.01 25.7 0.71 18.0 1.557 39.5 1-1/2 41 11-1/2 1.03 26.2 0.72 18.3 1.796 45.6 2 53 11-1/2 1.06 26.9 0.76 19.3 2.269 57
47、.6 2-1/2 63 8 1.57 39.9 1.14 29.0 2.720 69.1 Figure 7.1 Conduit thread dimensions FEBRUARY 16, 2006 ELECTRICAL INTERMEDIATE METAL CONDUIT STEEL - UL 1242 8 Table 7.1 Continued on Next PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL Table
48、 7.1 Continued Trade size (Metric designator) Number of threads per inch L 4 Total length of threads, a L 2 Effective length of threads, Pitch diameter E o at end of conduit, b inches (mm) inches (mm) inches (mm) 3 78 8 1.63 41.4 1.20 30.5 3.341 84.9 3-1/2 91 8 1.68 42.7 1.25 31.8 3.838 97.5 4 103 8
49、 1.73 43.9 1.30 33.0 4.334 110.1 a A minus tolerance of one thread applies to the total length of threads L 4 . b Plus or minus tolerances of one turn apply to the pitch diameter E o . 7.4 Taper of threads 7.4.1 The taper of threads shall be 3/4 inch per foot (1 in 16), and the perfect thread shall be tapered for its entire length. 8 Thread Gauging 8.1 The ring gauges to be used for the measurement of NPT threads as required in 7.3.1 shall have the dimensions ind
