1、NEMA Standards PublicationNational Electrical Manufacturers AssociationNEMA TCB 3-2001 (R2009)Users Manual for theInstallation ofUnderground CorrugatedCoilable Plastic UtilityDuct (CCD)NEMA Standards Publication TCB 3-2001 (R2009) Users Manual for the Installation of Underground Corrugated Coilable
2、Plastic Utility Duct (CCD) Published by: National Electrical Manufacturers Association 1300 North 17th Street, Suite 1752 Rosslyn, Virginia 22209 www.nema.org Reaffirmed October 7, 2009 Copyright 2002 by the National Electrical Manufacturers Association. All rights including translation into other l
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13、of the certifier or maker of the statement. TCB 3-2001 (R2009) Page i CONTENTS Page Foreword.ii Scope.iii Material Nomenclature iii Section 1 SELECTION OF DUCT 1.1 Types of Duct. 1 Section 2 HANDLING AND STORAGE 2.1 Transportation . 3 2.2 Storage 3 2.3 Job Site Handling 3 Section 3 INSTALLATION 3.1
14、Trenching and Shoring 5 3.2 Joining . 6 3.2.1 CCD to CCD Using Heat-Shrink Sleeve. 6 3.2.2 Joining CCD to CCD Using Solvent Cement Type Fitting-Mechanical Joint . 7 3.2.3 Self-Joining. 8 3.3 Dispensing and Placing Direct Burial 8 3.3.1 Horizontal Axis Dispensing. 8 3.3.2 Vertical Axis Dispensing. 9
15、3.3.3 Placing Single Duct Direct Burial. 10 3.3.4 Placing Multiple Duct Random Separation Direct Burial . 10 3.4 Dispensing and Placing Concrete Encased 11 3.4.1 Dispensing 11 3.4.2 Placing 11 3.5 Placing Duct Via Plow Technique . 11 3.5.1 Preliminary 11 3.5.2 Plowing . 12 3.6 Rodding . 12 3.6.1 Pne
16、umatic Rodding 12 3.6.2 Mechanical Rodding. 12 3.7 Mandrelling 12 Copyright 2002 by the National Electrical Manufacturers Association. TCB 3-2001 (R2009) Page ii Foreword The purpose of this manual is to provide assistance to engineers, superintendents, contractors, and foremen as a guide to obtain
17、the most appropriate and satisfactory installation of Corrugated Coilable Plastic Utility Duct (CCD). This manual is in no way intended to assume or replace any responsibilities of engineers, customer representatives, owners, or other persons in establishing engineering design and practices and proc
18、edures best suited to individual job conditions. The Engineering Department has worked closely with individual NEMA Subdivisions in the drafting of this manual and acknowledges the need for periodic review and updating. Proposed or recommended revisions should be submitted to: Vice President, Techni
19、cal Services National Electrical Manufacturers Association 1300 North 17th Street, Suite 1752 Rosslyn, Virginia 22209 Copyright 2002 by the National Electrical Manufacturers Association. TCB 3-2001 (R2009) Page iii Scope This manual covers recommendations for shipping, handling, storage, installatio
20、n, and joining of underground CCD for power, lighting, signaling, and communications applications. Material Nomenclature The plastic materials referenced in this document by the use of initials include the following: HDPE (High Density Polyethylene) CCD (Coiled Corrugated Duct) PP (Polypropylene) PV
21、C (Polyvinyl Chloride) Copyright 2002 by the National Electrical Manufacturers Association. TCB 3-2001 (R2009) Page iv Copyright 2002 by the National Electrical Manufacturers Association. TCB 3-2001 (R2009) Page 1 Section 1 SELECTION OF DUCT 1.1 TYPES OF DUCT CCD is designed for underground direct b
22、urial. It can, however, be concrete encased if required. Copyright 2002 by the National Electrical Manufacturers Association. TCB 3-2001 (R2009) Page 2 Copyright 2002 by the National Electrical Manufacturers Association. TCB 3-2001 (R2009) Page 3 Secton 2 HANDLING AND STORAGE 2.1 TRANSPORTATION a. T
23、he duct is normally shipped on reels or in coils. b. Abusive handling should be avoided. 2.2 STORAGE Store reels or coils lying flat on side. When stacking reels or coils or CCD, lay flat on a pallet. If placed outside for a considerable period of time (30 to 90 days), the stacks should be covered w
24、ith a UV inhibitor and plastic sheet so that moisture and sunrays will not damage package. See Figure 2-1. Figure 2-1 STORAGE OF REELS OR COILS NOTEReels or coils may be stacked three high for ease of handling. 2.3 JOB SITE HANDLING Do not let banded reels or coils drop in a free fall. When moving o
25、r carrying reels of CCD, be careful not to strike the surface with hard objects such as the jaws of a backhoe or forklift; this may cause damage to the duct. When loading and unloading from a truck or carrier, take care not to drop or hump the reels. A reel may be rolled into position with the shipp
26、ing bands attached. Do not cut shipping bands until ready for use. See Figure 2-2. Copyright 2002 by the National Electrical Manufacturers Association. TCB 3-2001 (R2009) Page 4 Figure 2-2 ROLLING A REEL INTO POSITION Copyright 2002 by the National Electrical Manufacturers Association. TCB 3-2001 (R
27、2009) Page 5 Section 3 INSTALLATION A duct system is considered to be properly installed if the inside diameter of each duct is adequate to allow free passage of the specified mandrel. Limiting the deflection, trench bedding, duct separation, type of backfill, and amount of compaction are factors re
28、quiring attention. 3.1 TRENCHING AND SHORING Observe all regulations pertaining to the excavation of open trenches. Review the layout drawings and ascertain that all necessary right of ways and trenching permits have been obtained. Coordinate the routing with all utility companies who may have under
29、ground lines in the area of the proposed trenching layout. In some localities under certain circumstances, it may be a requirement that two or more utilities must utilize the same trench. In this event, observe all federal, state, and local regulations dealing with this type of installation. Layout
30、and stake the routing of the trench. The trench dimensions are determined as follows: a. The depth is determined by the height of the duct bank, plus the minimum required cover over the bank. It is recommended that the minimum cover requirements listed in federal, state, and local, or the National E
31、lectrical Code be observed unless otherwise directed by the engineer. b. The width of the trench is determined by the width of the duct bank to be installed plus a minimum of 3-inch space on each side to adequately place and compact the backfill material. If shoring is required, additional trench wi
32、dth may be necessary. Where unstable or running soil condition is encountered in the trench wall, this condition should be stabilized before laying the duct. Depending upon the severity of the condition, the engineer may require the use of tight sheeting and/or stay bracing to control such condition
33、s. Well points or under drains may be required to control excessive ground water conditions. It is recommended that all applicable regulations be checked for shoring requirements. The trench bottom should be smooth and free of any debris that may be detrimental to the duct. If in an area where rocks
34、 prevail, a 4-inch bed of sand, sand slurry, decomposed granite or sandy loam should be added. In direct burial applications, if ducts are laid on the bottom of the trench, bedding must be uniformly graded to provide continuous support. Under no circumstances should blocking or mounding be used to r
35、aise the duct to grade. Where an unstable trench bottom is encountered it must be stabilized before laying duct. Usually, this can be accomplished by excavating an additional 4 inches or more. This over excavation is then replaced with a bedding of crushed stone or gravel to provide a high-density s
36、table base. This material should be suitably graded to act as an impervious mat through which the unstable soil will not penetrate. The maximum particle size of the bedding material should be inch. In addition, the following should be noted: Copyright 2002 by the National Electrical Manufacturers As
37、sociation. TCB 3-2001 (R2009) Page 6 a. Precautions IMPORTANT: To assure a proper bed for the duct, the trench bottom should be as level as possible, compacted, and free of loose soil, clods, or rocks. b. Encountering Rock In areas where rock is encountered, a minimum of 4 inches of sand or selected
38、 granular backfill should enclose the duct. The area for 12 inches above the duct should be free of rocks or hard objects that may endanger the duct. c. Width of Trench The width of the trench is determined by the number of ducts laid parallel, plus any required spacing between ducts. The trench wid
39、th should be wide enough to accommodate and allow for straightening of the duct. d. Changes of Direction Avoid unnecessary turns, dips or changes in direction. Keep bends as gradual as possible to assure ease of cable pull-in after duct installation. Maintain a grade or direction change of at least
40、10 to 1-ten foot of length for each one foot of elevation or direction change. Some short bends cannot be avoided. Examplea sweep to a pedestal. This type of bend can be made easily with CCD but the largest possible radius can be made if the lateral or pedestal trench is cut at an angle to main tren
41、ch. 3.2 JOINING 3.2.1 CCD to CCD Using Heat-Shrink Sleeve: a. Wipe all foreign matter from ends to be joined. b. Trim end of duct with knife to assure a smooth and continuous joint. c. Slip heat-shrink sleeve over one end of duct approximately 4 inches from end. d. Butt the two ends of duct together
42、. Wrap joint with one or two turns of tape to hold ends together. This will allow the joint to align itself and have sufficient mechanical strength to work freely while heating shrink sleeve. e. Slide heat-shrink sleeve over joint and center. Apply heat to heat-shrink sleeve. Use bottled gas torch w
43、ith regulator and shut-off valve. Flame should be as gentle as conditions permit; on windy days it may be necessary to use a higher pressure flame to concentrate the tip of flame. Start flame approximately 2 inches from end of heat-shrink sleeve and apply flame in a painting motion around the sleeve
44、. (Reflecting tape can be used to protect the duct while heating.) The sleeve will start to shrink in a matter of seconds. Take care not to get flame too close to area being heated. (It will distort the convolutions of duct and restrict the inside diameter.) Continue to paint flame over sleeve, work
45、ing in one direction until sleeve is fully shrunk. The convolutions of the duct will appear when shrinking has been accomplished. Allow the plastic to cool before placing any load on joint. Copyright 2002 by the National Electrical Manufacturers Association. TCB 3-2001 (R2009) Page 7 Figure 3-1 CCD
46、TO CCD USING HEAT-SHRINK SLEEVE NoteThe heat-shrink sleeve can also be used to join CCD to smoothwall duct, either steel or plastic. 3.2.2 Joining CCD to CCD Using Solvent Cement Type Fitting-Mechanical Joint CAUTION: The solvents used in these cements are flammable. Their fumes can be nauseous and
47、harmful if adequate ventilation is not provided. When cementing joints or fittings in confined spaces such as unventilated underground vaults or in small enclosed areas, forced ventilation systems should be provided and used. Being flammable, these cements must not be used where exposed to open flam
48、es, exposed heating elements, or sparks. Dont smoke when solvent-cementing joints. Read and observe the warnings and cautions clearly stated on the labels of solvent cement containers. a. Wipe all foreign matter from end of ducts to be joined. b. Use solvent cement of type normally used with ENT tub
49、ing. c. Apply solvent cement using a natural bristle brush to outside of CCD covering convolutions completely. Make sure there is a full, even coat over entire outside diameter of CCD for the depth of fitting to be joined to CCD. d. Apply a light, even coat of solvent cement to inside of fitting end to be joined to CCD. e. Slide fitting over end of duct using slight twisting motion. Make sure fitting is fully seated. Figure 3-2 CCD TO CCD USING SOLVENT CEMENT TYPE FITTING-MECHANICAL JOINT Copyright 2002 by the National Electrical Ma
