ANSI NEIS 111-2003 Standard for Installing Nonmetallic Raceways (RNC ENT LFNC).pdf
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1、Standard for InstallingNonmetallic Raceways (RNC, ENT, LFNC)NECA 111-2003AMERICAN NATIONAL STANDARDNational ElectricalContractors Association3 Bethesda Metro CenterSuite 1100 Bethesda, MD 20814301-657-3110 fax: 301-215-4500www.neca-neis.orgStandards cement will absorb mois-ture from the air.b) Follo
2、w manufacturer recommendations forselecting suitable solvent cement for the installationrequirements. Match temperature rating of cementto installation conditions.NOTE: Three types of cement are available for RNC,based on the viscosity: regular bodied, medium bodied,and heavy bodied. Regular bodied
3、cement is suitablefor most raceway applications up through 6 inches. Forbetter gap filling needs, a medium bodied cementshould be selected. For raceways, where a watertightjoint is needed, or for extremely hot weather use, selecta heavy bodied cement. For cement joints in corrugat-ed ENT, use manufa
4、cturer recommended ENT solventcement. Do not use PVC solvent cement on the threadsof threaded fittings.c) Wipe joint surfaces clean of dirt or moisture orother contaminants. Clean dirty or oil-coated race-way joining surfaces using PVC cleaner or primer inaccordance with manufacturer recommendations
5、.Thoroughly dry raceway joining surfaces. NOTE: Donot attempt to join raceways when any indication ofmoisture is present.d) Cool joint areas of raceways that are 90F orabove by shading or by applying a damp cloth.NOTE: Thoroughly dry raceways when using a dampcloth to cool raceways. Allow area to dr
6、y before apply-ing cement.NOTE: Hot raceway surfaces cause rapid drying of thecement, resulting in insufficient welding. Verify thatcement is liquid on raceway surfaces when joining thespigot and bell or fitting. Using a heavier, slower dry-ing cement may be appropriate when it is impracticalto cool
7、 the joints.e) Apply a full, even coat of cement to the entire areaof the spigot that will be inserted into the bell or fit-ting. Use the dauber applicator supplied in the lid ofthe cement container. Apply the cement quickly andevenly around the spigot and insert into the bell orfitting while the ce
8、ment is still liquid.f) Insert the spigot fully into the bell or fitting, twist-ing the spigot section one-quarter turn as insertion ismade. Hold the joint firmly together for 10 to 20seconds without movement. (NOTE: Cold weatherapplications may require a longer holding time.) If thespigot section b
9、acks out upon release, pull the jointapart, apply another coat of cement, and reassembleand hold until the joint does not back out uponrelease.NOTE: A small bead of cement should appear aroundthe lip of the bell or fitting if adequate cement has beenapplied. Wipe off excess bead after joint has set.
10、g) Carefully handle newly assembled joints until thecement has cured. If manufacturers recommenda-tions are unavailable, use minimum recommendedcuring times found in Table 4.9 Minimum CementCuring Time.4.9.1 Solvent Welding Fittings to ENTa) Use solvent cement or other PVC cement whichis specificall
11、y labeled for use with ENT.NOTE: Do not use heavy- or medium-bodied PVCcement or combinations of ABS and PVC cement.b) Remove all dust, dirt and moisture from ENT andfittings before applying cement. NOTE: Do not useprimer or cleaner.c) Apply solvent cement with the natural bristlebrush supplied in t
12、he can lid. NOTE: Do not use adauber.d) Apply a light, uniform coat of cement inside thesocket fitting. Apply a light, uniform coat of cementto the outside surface of the ENT to the depth of theNECA 111 Standard for Installing Nonmetallic Raceways (RNC, ENT, LFNC)a73 10Table 4.9 Minimum Cement Curin
13、g TimeTemperature TimeRange60 to 100F (15 to 40C) 30 minutes40 to 60F (5 to 15C) 1 hour20 to 40F (-5 to 5C) 2 hours0 to 20F (-20 to -5C) 4 hoursNote: Joint damage or loosening may occur up to48 hours after assembly in temperatures below40F, if the joints are severely stressed.fitting socket. Brush a
14、round the corrugations of theENT. NOTE: Do not brush longitudinally along theENT.e) Brush away any excess cement out of the groovesof the ENT.NOTE: Excess cement may cause burning and excesssoftening of the ENT which may result in joint failureunder stress.f) Quickly insert tubing into fitting while
15、 cement isstill wet up to the center stop of the fitting. Give thefitting a quarter turn and hold firmly in place for 15to 30 seconds. Do not disturb the fitting for two tofive minutes to allow firm joint set.4.10 Raceways Concealed in Masonry andConcretea) Tie raceway to reinforcing rods or support
16、 to pre-vent movement such as floating or sagging whenconcrete is placed. Locate spacers, if used, at inter-vals not exceeding the maximum spacing indicated inTable 4.10 Maximum Spacer Intervals.b) Rising temperature from curing concrete cancause expansion of the raceway. Pour concrete fromthe cente
17、r of the raceway run toward each free end orfrom one tie-in point toward the free end of the race-way. Make permanent terminal tie-ins after the tem-perature has normalized.c) Locate raceways in the middle third of cast-in-place slabs and walls and leave at least 1 inch con-crete cover. Place racewa
18、ys between bottom reinforc-ing steel and top reinforcing steel and run either par-allel or perpendicular to main reinforcing steel.When at right angles to reinforcement, place racewayclose to slab support.d) Provide a lateral separation of raceways not lessthan three raceway diameters except where t
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