VA 26 05 39-2009 UNDERFLOOR RACEWAYS FOR ELECTRICAL SYSTEMS.pdf

1、4-09 26 05 39 - 1 SECTION 26 05 39 UNDERFLOOR RACEWAYS FOR ELECTRICAL SYSTEMS SPEC WRITER NOTE: Delete between /-/ if not applicable to project. Also delete any other item or paragraph not applicable to the section and renumber the paragraphs. PART 1 - GENERAL 1.1 DESCRIPTION This section specifies

2、the furnishing, installation, and connection of the underfloor ducts to form a complete, coordinated, grounded raceway system. 1.2 RELATED WORK A. Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS: General electrical requirements that are common to more than one section of Division 26. B.

3、Section 26 05 21, LOW-VOLTAGE ELECTRICAL POWER CONDUCTORS AND CABLES (600 VOLTS AND BELOW): Wiring installed in the underfloor raceway system. C. Section 26 05 26, GROUNDING AND BONDING FOR ELECTRICAL SYSTEMS: Requirements for personnel safety and to provide a low impedance path to ground for possib

4、le ground fault currents. D. Section 26 27 26, WIRING DEVICES: Wiring devices, installed as part of the underfloor raceway system. 1.3 QUALITY ASSURANCE Refer to Paragraph, QUALIFICATIONS, in Section 26 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS. 1.4 SUBMITTALS A. In accordance with Section 26

5、 05 11, REQUIREMENTS FOR ELECTRICAL INSTALLATIONS, submit the following: B. Shop Drawings: 1. Identify components and accessories such as expansion-joint assemblies, straight raceway lengths, preset and afterset inserts, and service fittings. 2. Provide dimensions locating raceway header and distrib

6、ution elements. Include spacing between preset inserts and between preset inserts and ends of duct runs, walls, columns, junction boxes, and header duct connections. 3. Show connections between raceway elements and relationships between components and adjacent structural and architectural elements i

7、ncluding slab reinforcement, floor finish work, permanent partitions, and pre-tensioning or post-tensioning components. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4-09 26 05 39 - 2 4. Indicate height of preset inserts, junction boxes, and racewa

8、ys coordinated with depth of concrete slab and floor fill. 5. Indicate thickening of slabs where required for adequate encasement of raceway components. 6. Show details of connections and terminations of underfloor raceways to conduits. C. As-built Drawings: 1. Deliver four sets of drawings to the R

9、esident Engineer /COTR/ showing the exact location of all underfloor ducts and junction boxes dimensioned from the centerline of columns. 2. Show the location and circuiting of all power service outlet fittings. 3. Show the location of all telephone and data service fittings. D. Manuals: 1. Provide

10、a complete description of the system and instructions as to allow additions to, and proper maintenance of the system. Instructions shall include information on locating and installing inserts of preset and afterset types. 2. Two weeks prior to final inspection, submit four copies of the manuals to t

11、he Resident Engineer. E. Certifications: 1. Two weeks prior to final inspection, submit four copies of the following to the Resident Engineer: 2. Certification that the materials are in accordance with the drawings specifications. 3. Certification that all materials have been properly installed. 1.5

12、 APPLICABLE PUBLICATIONS A. Publications listed below (including amendments, addenda, revisions, supplements, and errata) form a part of this specification to the extent referenced. Publications are referenced in the text by the basic designation only. B. Underwriters Laboratories, Inc. (UL): 884 Un

13、derfloor Raceways and Fittings C. National Fire Protection Association (NFPA): 70 . National Electrical Code (NEC) PART 2 - PRODUCTS 2.1 RACEWAYS, UNDERFLOOR A. UL 884 shall apply. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4-09 26 05 39 - 3 B.

14、Raceways: SPEC WRITER NOTE: Specify the physical size of the underfloor raceway. Include specifications for radiology suite trench duct. Raceway in MRI suites should be non-ferrous. 1. The duct shall have outside dimensions of / 3-1/8 inch 79mm x 1-1/4 inch 32mm x 6-1/2 inch 165mm x 1 1/2 inch 38mm

15、/ / /. 2. Preset inserts shall be spaced 24 inches 600mm on centers and shall not be less than 2-1/4 inches 58mm in diameter. 3. Shall not be less than No. 14 gage steel, continuously welded with corrosion resistant coating, inside and outside. 4. Shall have rounded corners. 5. Shall have vertical 9

16、0 degree elbows for upwall extension. 6. Shall have horizontal 90 degree and 45 degree elbows for turning corners. 7. Shall have all appurtenance for complete installation, such as blank washers, terminal bushings, end caps, etc. 8 Power and telecommunications raceways shall be separate, and shall h

17、ave cross-sectional areas which are not less than the dimensions indicated on the drawings. Combination of raceways, fittings, inserts, junction boxes, service fittings, and mounting and connection arrangements for wiring devices and jacks shall provide a 2 inch (50mm) minimum bending radius for tel

18、ecommunication cables. 9. Shall be complete with manufactured adjustable supports, couplings, elbows, enclosure fittings and associated components. C. Junction Boxes: 1. Shall be cast metal or formed steel with corner conduit adapters and corrosion-resistant coating, inside and outside. 2. Each box

19、shall have four screws for adjustment and leveling after installation. 3. Boxes shall have adjustable covers. 4. Coverplates shall be removable and the proper depth for and coordinated with the floor coverings and finishes. D. Service fittings: 1. Shall be the low compact type, satin-finished alumin

20、um. 2. Power outlets shall have receptacles as indicated and as specified in Section 26 27 26, WIRING DEVICES. 3. Telecommunications outlets shall have dimensions which are approximately the same as the power outlets. Data, telephone and other telecommunications jacks shall be as required by the app

21、licable specifications. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4-09 26 05 39 - 4 4. Include mounting, hinged cover, and trim to support and provide access to connector, jack, or receptacle devices mounted flush with floor within insert. PART

22、 3 - EXECUTION 3.1 INSTALLATION A. Installation shall be in accordance with the NEC, manufacturers recommendations and as shown on the drawings. B. Connect the raceways, boxes and fittings so they are mechanically firm, electrically continuous and watertight. C. Align, level and make the raceways pa

23、rallel to or at right angles with the building walls. D. Raceways shall be free from burrs, sharp edges, dents and other defects. E. Cap or plug unused openings with standard fittings. F. Install marking screw insert caps at inserts which are adjacent to the junction boxes, at each end of the racewa

24、y runs and on both sides of permanent walls. Marking screws shall be flush with the finished floors. G. Fasten the junction boxes firmly in place to prevent their movement during pouring of the slabs. H. Raceway systems shall be supported at not more than 1500 mm (five foot) centers. I. Specific met

25、hods of installing the raceways shall be demonstrated to and approved by the Resident Engineer prior to performing the basic floor installation work. J. Branch circuit wiring shall be the same as that specified for the project for wet locations in Section 26 05 21, LOW-VOLTAGE ELECTRICAL POWER CONDU

26、CTORS AND CABLES (600 VOLTS AND BELOW). K. Provide a vapor barrier be installed in any slab on grade construction. Provide welded wire fabric, or mesh, installed in the top 1“ 25mm of the concrete slab to limit cracks in the slab due to expansion and contraction from temperature variations. L. No co

27、ncrete containing chlorides from any source shall be placed over or in contact with infloor units. Concrete shall be vibrated at all headers, junction boxes and duct to insure that the concrete completely fills underneath the duct system. Shrinkage and temperature reinforcement above the duct system

28、s shall be in accordance with ACI318-83. Care shall be taken during concrete placement and, in particular, during concrete vibration, to prevent rising of top reinforcement within the slab. Contractors placing the concrete shall carefully hand finish a minimum of 24 inches (610mm) adjacent to juncti

29、on box access openings so that the top of finished concrete and junction box access openings are flush with each other. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4-09 26 05 39 - 5 M. Protect underfloor raceway system from damage. Do not use the

30、 installed duct system as working platforms or walkways. Do not allow equipment or heavy traffic over duct during construction period, without first installing ramps over the duct. Ramps shall be designed so that imposed loads are not transferred to the duct. Components of the system which are damag

31、ed during construction shall be replaced. N. Provide expansion fittings with suitable bonding jumper where raceway crosses building expansion joints. O. Install junction box tops flush and level with finished floor. Install blank closure plates or plugs to close unused junction box openings. Grout b

32、oxes in place to prevent movement during construction. Place top covers in inverted position during construction to prevent damage to surface of cover. Reinstall covers in proper position prior to final acceptance of work. 3.2 TOOLS Deliver a complete set of tools for future field installation of outlets and devices to the Resident Engineer. Include a battery-operated electronic insert finder. - - - E N D - - - Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-