1、NEMA Standards PublicationNational Electrical Manufacturers AssociationNEMA TC 6 b) 11164 (with a minimum tensile strength of 4,000 psi (28 mPa) and a minimum modulus of elasticity in tension of 500,000 psi (3,450 mPa) as defined in ASTM D 1784; c) 11321 as defined in ASTM D 4396. Other PVC compound
2、s which have a cell classification which results in the products properties being superior to those of the compounds specified above may also be used. Clean, reworked material, and recycled, post-industrial material may be used, provided that the duct produced shall meet the requirements of this sta
3、ndard. 3.1.2 Solvent Cements and Primers PVC solvent cements shall be in accordance with ASTM D 2564. PVC primers shall be in accordance with ASTM F 656. ASTM F 402 is referenced as recommended practice for safe handling of solvent cements. 3.1.3 Gaskets and Lubricants Elastomeric seals (gaskets) sh
4、all be in accordance with ASTM F 477 for low-head applications. Gaskets and lubricants and plastic materials shall be made from materials that are compatible. 3.2 COLOR PVC duct should be either gray or white in color. Other colors are acceptable if agreed to by the parties involved. 3.3 DIMENSIONS
5、AND LENGTHS 3.3.1 Duct Dimensions Dimensions shall meet the requirements of Table 3-1 when determined in accordance with Section 5.2. Trade Sizes and Metric Designators used throughout this standard are for identification purposes only, and are not actual dimensions. 3.3.2 Duct Length The overall le
6、ngth (including the integral bell or coupling) is commonly: 20 ft + 1 in. 0 in. (6.10 m + 25 mm 0 mm) TC 6 & 8-2013 Page 5 2013 National Electrical Manufacturers Association Other lengths are acceptable if agreed to by the parties involved. 3.3.3 Chamfer Dimensions The inside diameter of the spigot
7、ends shall be chamfered as shown in Figure 3-1. Figure 3-1 CHAMFER DIMENSIONS 3.3.4 Joint Dimensions Dimensions for integral belled ends shall conform to the requirements of Sections 3.4.3 or 3.4.4. 3.4 JOINTS 3.4.1 Joint Types Two types of joining systems are used to join duct: solvent-cemented joi
8、nts and gasketed joints. Joints shall be made with either the use of fittings or integral belled ends on the duct. 3.4.2 Fittings Solvent-cemented fittings used to join duct shall conform to the requirements of NEMA TC 9. Gasketed fittings shall meet the joint-leakage requirements of Section 4.1. 2.
9、 3.4.3 Integral Belled Ends for Solvent-Cemented Joints The wall thickness of an integral belled ends shall be considered satisfactory if formed from duct meeting the requirements of this standard. Integral belled ends shall be centered to provide a visible shoulder around the entire circumference o
10、f the duct. TC 6 & 8-2013 Page 6 2013 National Electrical Manufacturers Association Connector 6 mm (1/4 in.) Gauge Thickness Gauge Diameter Two systems of fit for integral belled ends are in common use: clearance fit and interference fit. Dimensions for integral belled ends shall be in accordance wi
11、th Table 3-2 for clearance fit or Table 3-3 for interference fit. The inside-diameter dimensions of an integral belled end shall be considered satisfactory if it accepts the appropriate Go/No-Go gauges as specified in Table 3-4 for clearance fit or Table 3-5 for interference fit. The Go/No-Go gauges
12、 are typically machined from in. (6 mm) thickness steel into a full circle gauge (see Figure 3-2). The gauge is intended for use on the production line by the extruder operator to continually check the dimension at the integral belled ends. The “Go” end is typically painted green, while the “No-Go”
13、end is painted red. Actual gauge dimensions are commonly marked on each end. Figure 3-2 TYPICAL GO/NO-GO GAUGE Integral belled socket depths shall be in accordance with Table 3-2 or Table 3-3. Integral bell socket depth shall be measured with an instrument accurate to 1/16 in. ( 1 mm). A tape measur
14、e or steel rule is acceptable. Integral belled ends designed for solvent cementing shall meet the joint leakage requirement of Section 4.1.1. 3.4.4 Integral Belled Ends for Gasketed Joints The wall thickness of an integral belled end shall be considered satisfactory if formed from duct meeting the r
15、equirements of this standard. Integral belled ends shall be centered to provide a visible shoulder around the entire circumference of the duct. Gasketed-joint dimensions shall be determined by the manufacturer. Joints employing gaskets (elastomeric seals) are intended to be watertight. Integral bell
16、ed ends with gaskets shall meet the joint leakage requirements of Section 4.1.2. TC 6 & 8-2013 Page 7 2013 National Electrical Manufacturers Association 3.5 INSPECTIONS The manufacturer shall inspect the duct at time of manufacture for compliance to dimensional and performance requirements of this s
17、tandard, and for freedom from defects, as defined in Section 4.2. TC 6 & 8-2013 Page 8 2013 National Electrical Manufacturers Association Table 3-1 DIMENSIONS OF UNDERGROUND UTILITIES DUCT U.S. CUSTOMARY UNITS (inches) Trade Size Metric Designators Outside Diameter Average Tolerance Out-of-Roundness
18、1 1 27 1.315 0.005 .060 1 41 1.900 0.006 .060 2 53 2.375 0.006 .060 3 78 3.500 0.008 .060 3 91 4.000 0.008 .100 4 103 4.500 0.009 .100 5 129 5.563 0.010 .100 6 155 6.625 0.011 .100 1 “Out-of-Roundness” is defined as maximum diameter minus minimum diameter. Trade Size Metric Designators Minimum Wall
19、Thickness2 Minimum Modulus of Elasticity 400,000 psi EB-20 EB-35 DB-60 DB-100 DB-120 1 27 - - - - 0.060 1 41 - - 0.060 - 0.065 2 53 - 0.060 0.065 - 0.083 3 78 0.067 0.082 0.100 0.121 0.127 3 91 0.078 0.095 0.115 0.138 0.147 4 103 0.089 0.109 0.131 0.155 0.166 5 129 0.112 0.136 0.164 0.192 0.205 6 15
20、5 0.135 0.164 0.196 0.229 0.244 2Tolerance on wall thickness is +0.030, - 0.000 in. Trade Size Metric Designators Minimum Wall Thickness2 Minimum Modulus of Elasticity 500,000 psi EB-20 EB-35 DB-60 DB-100 DB-120 1 27 - - - - 0.060 1 41 - - - - 0.060 2 53 0.060 0.060 0.060 - 0.077 3 78 0.061 0.076 0.
21、092 0.112 0.118 3 91 0.072 0.088 0.107 0.128 0.136 4 103 0.082 0.100 0.121 0.145 0.154 5 129 0.103 0.126 0.152 0.179 0.191 6 155 0.125 0.152 0.182 0.213 0.227 2Tolerance on wall thickness is +.030 - 0 in. TC 6 & 8-2013 Page 9 2013 National Electrical Manufacturers Association Table 3-1 (Cont.) METRI
22、C UNITS (millimeters) Metric Designators Outside Diameter Average Tolerance Out-of-Roundness1 27 33.81 0.13 1.52 41 48.26 0.15 1.52 53 60.33 0.15 1.52 78 88.90 0.20 1.52 91 101.60 0.20 2.54 103 114.30 0.23 2.54 129 141.30 0.25 2.54 155 168.28 0.28 2.54 1 “Out-of-Roundness” is defined as maximum diam
23、eter minus minimum diameter. Minimum Wall Thickness2 Minimum Modulus of Elasticity 400,000 psi Metric Designators EB-20 EB-35 DB-60 DB-100 DB-120 27 - - - - 1.52 41 - - 1.52 - 1.65 53 - 1.52 1.65 - 2.11 78 1.70 2.08 2.54 3.07 3.23 91 1.98 2.41 2.92 3.51 3.73 103 2.26 2.77 3.33 3.94 4.22 129 2.84 3.4
24、5 4.17 4.88 5.21 155 3.43 4.17 4.98 5.82 6.20 2Tolerance on wall thickness is +0.76, - 0.00 mm. Minimum Wall Thickness2 Minimum Modulus of Elasticity 500,000 psi Metric Designators EB-20 EB-35 DB-60 DB-100 DB-120 27 - - - - 1.52 41 - - - - 1.52 53 1.52 1.52 1.52 - 1.96 78 1.55 1.93 2.34 2.84 3.00 91
25、 1.83 2.24 2.72 3.25 3.45 103 2.08 2.54 3.07 3.68 3.91 129 2.62 3.20 3.86 4.55 4.85 155 3.18 3.86 4.62 5.41 5.77 2Tolerance on wall thickness is +0.76, - 0.00 mm. TC 6 & 8-2013 Page 10 2013 National Electrical Manufacturers Association Table 3-2 INTEGRAL BELLED END DIMENSIONS (Clearance Fit) U.S. CU
26、STOMARY UNITS (inches) Trade Size Metric Designators Average Socket Entrance ID Average Socket Bottom ID Tolerance on ID Out-of-Roundness1 Minimum Socket Depth 1 27 1.331 1.320 0.005 0.060 1.000 1 41 1.921 1.906 0.006 0.060 1.375 2 53 2.400 2.381 0.006 0.060 1.750 3 78 3.538 3.508 0.008 0.060 2.875
27、3 91 4.041 4.008 0.008 0.100 3.125 4 103 4.544 4.509 0.009 0.100 3.375 5 129 5.614 5.573 0.010 0.100 4.000 6 155 6.687 6.636 0.011 0.100 5.000 1 “Out-of-Roundness” is defined as maximum diameter minus minimum diameter. METRIC UNITS (millimeters) Metric Designators Average Socket Entrance ID Average
28、Socket Bottom ID Tolerance on ID Out-of- Roundness1 Minimum Socket Depth 27 33.81 33.53 0.13 1.52 25.40 41 48.79 48.41 0.15 1.52 34.93 53 60.96 60.48 0.15 1.52 44.45 78 89.87 89.10 0.20 1.52 73.03 91 102.64 101.80 0.20 2.54 79.38 103 115.42 114.53 0.23 2.54 85.73 129 142.60 141.55 0.25 2.54 101.60 1
29、55 169.85 168.55 0.28 2.54 127.00 1 “Out-of-Roundness” is defined as maximum diameter minus minimum diameter. TC 6 & 8-2013 Page 11 2013 National Electrical Manufacturers Association Table 3-3 INTEGRAL BELLED END DIMENSIONS (Interference Fit) U.S. CUSTOMARY UNITS (inches) Trade Size Metric Designato
30、rs Average Socket Entrance ID Average Socket Bottom ID Tolerance on ID Out-of-Roundness1 Minimum Socket Depth 1 27 1.325 1.310 0.005 0.020 0.875 1 41 1.912 1.894 0.006 0.024 1.094 2 53 2.387 2.369 0.006 0.024 1.156 3 78 3.516 3.492 0.008 0.030 1.875 3 91 4.016 3.992 0.008 0.030 2.000 4 103 4.518 4.4
31、91 0.009 0.030 2.000 5 129 5.583 5.553 0.010 0.060 3.000 6 155 6.647 6.614 0.011 0.060 3.000 1 “Out-of-Roundness” is defined as maximum diameter minus minimum diameter. METRIC UNITS (millimeters) Metric Designators Average Socket Entrance ID Average Socket Bottom ID Tolerance on ID Out-of- Roundness
32、1 Minimum Socket Depth 27 33.66 33.27 0.13 0.51 22.23 41 48.56 48.11 0.15 0.61 27.79 53 60.63 60.17 0.15 0.61 29.36 78 89.31 88.70 0.20 0.76 47.63 91 102.01 101.40 0.20 0.76 50.80 103 114.76 114.07 0.23 0.76 50.80 129 141.81 141.05 0.25 1.52 76.20 155 168.83 168.00 0.28 1.52 76.20 1 “Out-of-Roundnes
33、s” is defined as maximum diameter minus minimum diameter. TC 6 & 8-2013 Page 12 2013 National Electrical Manufacturers Association Table 3-4 GO/NO-GO GAUGES (Clearance Fit) U.S. CUSTOMARY UNITS (inches) Trade Size Metric Designators Socket Entrance Go Gauge OD No-Go Gauge OD Socket Bottom Go Gauge O
34、D No-Go Gauge OD 1 27 1.326 1.337 1.315 1.326 1 41 1.915 1.928 1.900 1.913 2 53 2.394 2.407 2.375 2.388 3 78 3.530 3.547 3.500 3.517 3 91 4.033 4.050 4.000 4.017 4 103 4.535 4.554 4.500 4.519 5 129 5.604 5.625 5.563 5.584 6 155 6.676 6.699 6.625 6.648 Tolerances +0.0/-0.001 +0.001/-0.0 +0.0/-0.001 +
35、0.001/-0.0 METRIC UNITS (millimeters) Metric Designators Socket Entrance Go Gauge OD No-Go Gauge OD Socket Bottom Go Gauge OD No-Go Gauge OD 27 33.68 33.96 33.40 33.68 41 48.64 48.97 48.26 48.59 53 60.81 61.14 60.33 60.66 78 89.66 90.09 88.90 89.33 91 102.44 102.87 101.60 102.03 103 115.19 115.67 11
36、4.30 114.78 129 142.34 142.88 141.30 141.83 155 169.57 170.15 168.28 168.86 Tolerances +0.0/-0.03 +0.03/-0.0 +0.0/-0.03 +0.03/-0.0 TC 6 & 8-2013 Page 13 2013 National Electrical Manufacturers Association Table 3-5 GO/NO-GO GAUGES (Interference Fit) U.S. CUSTOMARY UNITS (inches) Trade Size Metric Des
37、ignators Socket Entrance Go Gauge OD No-Go Gauge OD Socket Bottom Go Gauge OD No-Go Gauge OD 1 27 1.320 1.331 1.305 1.316 1 41 1.906 1.919 1.888 1.901 2 53 2.381 2.394 2.363 2.376 3 78 3.508 3.525 3.484 3.501 3 91 4.008 4.025 3.984 4.001 4 103 4.509 4.528 4.482 4.501 5 129 5.573 5.594 5.543 5.564 6
38、155 6.636 6.659 6.603 6.626 Tolerances +0.0/-0.001 +0.001/-0.0 +0.0/-0.001 +0.001/-0.0 METRIC UNITS (millimeters) Metric Designators Socket Entrance Go Gauge OD No-Go Gauge OD Socket Bottom Go Gauge OD No-Go Gauge OD 27 33.53 33.81 33.15 33.43 41 48.41 48.74 47.96 48.29 53 60.48 60.81 60.02 60.35 78
39、 89.10 89.54 88.49 88.93 91 101.80 102.24 101.19 101.63 103 114.53 115.01 113.84 114.33 129 141.55 142.09 140.79 141.33 155 168.55 169.14 167.72 168.30 Tolerances +0.0/-0.02 +0.02/-0.0 +0.0/-0.02 +0.02/-0.0 TC 6 & 8-2013 Page 14 2013 National Electrical Manufacturers Association Section 4 PERFORMANC
40、E REQUIREMENTS 4.1 QUALIFICATION TEST 4.1.1 Leakage at Solvent Cemented Joints Solvent cemented joints between ducts and their respective fittings and/or integral belled ends shall not leak when tested in accordance with the following steps: a) Solvent cement the joint. b) After assembly, allow the
41、joint to stand for 24 hours. c) Using water as the medium, subject the joint to an internal or external pressure of 25 psi (172 kPa) for one hour. 4.1.2 Leakage at Gasketed Duct Joints Gasketed duct joints shall not leak when tested in accordance with ASTM F 1365. 4.2 QUALITY CONTROL TESTS 4.2.1 Def
42、inition A quality control test is an in-plant test that is conducted on a given test frequency to verify whether a product remains conformant to this standard. 4.2.2 Conditioning At the time of production, measurements and performance test are made at the ambient temperature within the factory. In c
43、ase of disagreement, specimens shall be conditioned in accordance with Section 5.1.1. 4.2.3 Workmanship Duct shall be free from visible cracks, holes, foreign inclusions, or other defects. 4.2.4 Impact resistance The minimum drop-weight impact-test values shall be as listed in Table 4-1 when tested
44、in accordance with Section 5.5. Impact-resistance tests are quality control tests intended to verify that the duct has been properly extruded. The tests are not intended to represent field conditions. When the test criteria is applied to the duct within 48 hours of manufacture, the duct has been fou
45、nd by experience to be adequate for handling, transport, and installation. The actual impact-resistance strength is generally higher, but varies because it is dependent on specific material formulation, specific extrusion machine, and specific extrusion procedures. Changes in formulation to obtain m
46、aximum impact resistance may result in lesser values in other parameters such as deflection resistance. Exposure of PVC duct to ultraviolet (UV) radiation results in a measurable decrease in impact resistance. Therefore, impact-resistance values are applicable only at time of manufacture and TC 6 &
47、8-2013 Page 15 2013 National Electrical Manufacturers Association are not applicable for yard-aged duct. However, initial impact values set by the standard are higher than necessary for normal handling and installation. TC 6 & 8-2013 Page 16 2013 National Electrical Manufacturers Association Table 4
48、-1 MINIMUM IMPACT-RESISTANCE VALUES FOR DUCT Minimum Impact Resistance at 32F (0C) Trade Metric EB-20 EB-35 DB-60 DB-100 DB-120 Size Designators ft-lbf (J) ft-lbf (J) ft-lbf (J) ft-lbf (J) ft-lbf (J) 1 27 - - - - - - - - 10 (14) 1 41 - - - - 10 (14) - - 15 (20) 2 53 20 (27) 20 (27) 20 (27) 25 (34) 2
49、5 (34) 3 78 20 (27) 30 (41) 40 (54) 45 (61) 50 (68) 3 91 20 (27) 35 (47) 50 (68) 60 (81) 65 (88) 4 103 25 (34) 40 (54) 60 (81) 70 (95) 80 (108) 5 129 30 (41) 55 (75) 85 (115) 100 (136) 110 (149) 6 155 40 (54) 75 (102) 120 (163) 135 (183) 150 (203) 4.2.5 Duct Stiffness The minimum duct-stiffness values for
