UL 1242-2006 UL Standard for Safety Electrical Intermediate Metal Conduit C Steel (Fourth Edition Reprint with Revisions Through and Including June 25 2018)《电气过渡金属钢导管》.pdf

1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL 1242 Electrical Intermediate Metal Conduit Steel STANDARD FOR SAFETYUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM ULUL COPYRIGHTED M

2、ATERIAL NOT AUTHORIZED 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 This revision to ANSI/UL 1242 includes a clarication to Table 9.1. Text

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8、8 UL 1242 tr1UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL JUNE 25, 2018 UL 1242 tr2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL FEBRUARY 16, 2006 (Title Pa

9、ge Reprinted: June 25, 2018) 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 consists of the Fourth Edition, including revisions through

10、 June 25, 2018. The most recent designation of ANSI/UL 1242 as an American National Standard (ANSI) occurred on June 25, 2018. ANSI approval for a standard does not include the Cover Page, Transmittal Pages, and Title Page. The Department of Defense (DoD) has adopted UL 1242 on May 21, 1984. The pub

11、lication 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 submitted via a Proposal Request in ULs On-Line Collaborative Standards Developmen

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13、COPYRIGHT 2018 UNDERWRITERS LABORATORIES INC. ANSI/UL 1242-2018UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL MARCH 5, 2014 ELECTRICAL INTERMEDIATE METAL CONDUIT STEEL - UL 1242 2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED F

14、OR 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 .6 6.2 Surface treatments 6A 6.3 Supplementary coatings .7 6.4 Alternate corrosion

15、-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 Couplings 12 PERFORMANCE 13 Identication of Compounds 14 14 Bending .14 14.1 Ambie

16、nt 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 Impact Test .22 18 Flammability Test .22 18.1 General .22 18.2 Preparations 22 18.3 Conduct

17、 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 REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL EXAMINATION OF FINISHED PRODUCT

18、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 INTRODUCTION 1 Scope 1.1 These requirements cover steel electrical intermediate metal cond

19、uit (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 Code (NEC), NFPA 70. The values in parentheses are metric designators of conduit. 1.2 Stee

20、l 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. 2 Units of Measurement 2.1 Values stated without parentheses are the requirement. Valu

21、es 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 interpreted as referring to the latest edition of that code or standard. 4 Glossary 4.1 For purposes of this standard the

22、 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 provide the level of corrosion resistance required on the exterior of conduit. Coatings may include zinc. See 15.2.

23、 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 necessary where the coating is not subject to physical damage, such as on the interior of conduit. The coatings may includ

24、e 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 the exterior or interior of the conduit as applicable. See 15.1. JUNE 25, 2018 ELECTRICAL INTERMEDIATE METAL CONDU

25、IT 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 of steel or stainless steel. 5.2 Each tube shall have a circular cross section, thereby facilitating the cutting of

26、 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 bead 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 diamet

27、er 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 protective coating is applied, the interior and exterior surfaces of each tube shall be free from scale, ash, or any other protrusion. 6 Prot

28、ective 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 coating. 6.1.2 The interior surface of the steel conduit shall be protected against corrosion by an organic or zinc coating. 6.1.3 Conduit an

29、d ttings constructed of stainless steel are not required to be provided with interior or exterior protective coatings. JUNE 25, 2018 ELECTRICAL INTERMEDIATE METAL CONDUIT STEEL - UL 1242 6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 6.2 S

30、urface treatments 6.2.1 When one or more surface treatments not exceeding 0.00015 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 C

31、ONDUIT STEEL - UL 1242 6AUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION 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 DISTRIBUTI

32、ON WITHOUT PERMISSION FROM UL 6.3 Supplementary coatings 6.3.1 The use of one 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

33、 supplementary coatings that have not been evaluated as furnishing corrosion-resistance 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 t

34、he primary protective coating, the t of couplings, and electrical continuity with 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 corrosi

35、on-resistant coating that is not marked with a temperature designation, or is 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

36、 higher rating that has been evaluated in accordance with Section 15.2. See 21.6. 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 provi

37、ded with a nonmetallic alternate corrosion-resistant coating that is for use 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,

38、or straight length of conduit shall be threaded on both ends. Each end shall 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 ope

39、ration of the cleaning process are susceptible to being eaten away by the acid 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

40、condition is to be corrected by recutting the threads, or the tube is to be 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 Protectio

41、n of threads 7.2.1 Threads are to be given a protective coating to prevent corrosion 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

42、 with the dimensions of the NPT (National Pipe Taper) thread outlined in Figure 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 thr

43、eads, a L 2 Effective length of threads, Pitch diameter E o at end of conduit, 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

44、-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 57.6 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 AUTHORIZ

45、ED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL Table 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

46、 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 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

47、 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 indicated in Table 8.1. The gauging information and practice

48、 for pipe threads are in accordance with ASME B1.20.1, Pipe Threads, General Purpose (Inch) Revision and Redesignation of ASME/ANSI B2.1-1968 Table 8.1 Ring-gauge dimensions Trade size (Metric designator) Gauge length L 1 , Pitch diameter E 1 , inch (mm) threads inches (mm) 1/2 16 0.320 8.13 4.48 0.

49、7784 19.77 3/4 21 0.339 8.61 4.75 0.9889 25.12 1 27 0.400 10.16 4.60 1.2386 31.46 1-1/4 35 0.420 10.67 4.83 1.5834 40.22 1-1/2 41 0.420 10.67 4.83 1.8223 46.29 2 53 0.436 11.07 5.01 2.2963 58.33 2-1/2 63 0.682 17.32 5.46 2.7622 70.16 3 78 0.766 19.46 6.13 3.3885 86.07 3-1/2 91 0.821 20.85 6.57 3.8888 98.78 4 103 0.844 21.44 6.75 4.3871 111.43 FEBRUARY 16, 2006 ELECTRICAL INTERMEDIATE METAL CONDUIT STEEL - UL 1242 9UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHE