260543 - Underground Ducts and Raceways for Electrical Systems.pdf

TABLE OF CONTENTS

SECTION 260543 – UNDERGROUND DUCTS AND RACEWAYS FOR ELECTRICAL SYSTEMS

PART 1 - GENERAL

1.1 RELATED DOCUMENTS

1.2 SUMMARY

1.3 DEFINITIONS

1.4 ACTION SUBMITTALS

1.5 MAINTENANCE MATERIALS SUBMITTALS

1.6 FIELD CONDITIONS

PART 2 - PRODUCTS

2.1 METAL CONDUIT AND FITTINGS

2.2 RIGID NONMETALLIC DUCT

2.3 FLEXIBLE NONMETALLIC DUCTS

2.4 DUCT ACCESSORIES

PART 3 - EXECUTION

3.1 PREPARATION

3.2 UNDERGROUND DUCT APPLICATION

3.3 EARTHWORK

3.4 DUCT AND DUCT-BANK INSTALLATION

3.5 GROUNDING

3.6 FIELD QUALITY CONTROL

3.7 CLEANING

BETHANY MIDDLE SCHOOL JUNE 6, 2025

FIRE PUMP REPLACEMENT VAN ZELM #2024090.00

UNDERGROUND DUCTS AND RACEWAYS FOR ELECTRICAL SYSTEMS 260543 - 1

SECTION 260543 - UNDERGROUND DUCTS AND RACEWAYS FOR ELECTRICAL SYSTEMS

PART 1 - GENERAL

1.1 RELATED DOCUMENTS

A. Drawings and general provisions of the Contract, including General and Supplementary Conditions and Division 01 Specification Sections, apply to this Section.

B. THIS PROJECT WILL BE COMMISSIONED. REFER TO COMMISSIONING

SPECIFICATION SECTIONS FOR COMMISSIONING INFORMATION AND

REPSONSIBILITIES. THE COMMISSIONING PROCESS WILL REQUIRE ADDITIONAL

LABOR, MATERIAL AND/OR OTHER COSTS WHICH MUST BE PROVIDED BY THE

CONTRACTOR AS PART OF THIS PROJECT.

1.2 SUMMARY

A. Section Includes:

1. Metal conduits and fittings, including GRC and PVC-coated steel conduit.

2. Rigid nonmetallic duct.

3. Flexible nonmetallic duct.

4. Duct accessories.

1.3 DEFINITIONS

A. Direct Buried: Duct or a duct bank that is buried in the ground, without any additional casing materials such as concrete.

B. Duct: A single duct or multiple ducts. Duct may be either installed singly or as component of a duct bank.

C. Duct Bank:

1. Two or more ducts installed in parallel, with or without additional casing materials.

2. Multiple duct banks.

D. GRC: Galvanized rigid (steel) conduit.

E. Trafficways: Locations where vehicular or pedestrian traffic is a normal course of events.

1.4 ACTION SUBMITTALS

A. Product Data: For each type of product.

UNDERGROUND DUCTS AND RACEWAYS FOR ELECTRICAL SYSTEMS 260543 - 2

1. Include duct, conduits, and their accessories, including elbows, end bells, bends, fittings, and solvent cement.

2. Include underground-line warning tape.

3. Include warning planks.

1.5 MAINTENANCE MATERIALS SUBMITTALS

A. Furnish extra materials that match products installed and that are packaged with protective covering for storage and identified with labels describing contents.

B. Furnish cable-support stanchions, arms, insulators, and associated fasteners in quantities equal to 5 percent of quantity of each item installed.

1.6 FIELD CONDITIONS

A. Interruption of Existing Electrical Service: Do not interrupt electrical service to facilities occupied by Owner or others unless permitted under the following conditions, and then only after arranging to provide temporary electrical service according to requirements indicated:

1. Notify Architect, Construction Manager, and Owner no fewer than fourteen days in advance of proposed interruption of electrical service.

2. Do not proceed with interruption of electrical service without Architect's written permission.

B. Ground Water: Assume ground-water level is at grade level unless a lower water table is noted on Drawings.

PART 2 - PRODUCTS

2.1 METAL CONDUIT AND FITTINGS

A. GRC: Comply with ANSI C80.1 and UL 6.

B. Subject to compliance with requirements, available Manufacturers offering products that may be incorporated into the work include, but are not limited to the following:

1. Allied Tube & Conduit

2. OMNI

3. Perma-Cote

4. Republic Conduit

5. Thomas & Betts Corporation

6. Wheatland Tube Company

C. Coated Steel Conduit: PVC-coated GRC.

1. Comply with NEMA RN 1.

2. Coating Thickness: 0.040 inch, minimum.

UNDERGROUND DUCTS AND RACEWAYS FOR ELECTRICAL SYSTEMS 260543 - 3

D. Listed and labeled as defined in NFPA 70, by a nationally recognized testing laboratory, and marked for intended location and application.

2.2 RIGID NONMETALLIC DUCT

A. Underground Plastic Utilities Duct: Type EPC-40-PVC RNC, complying with NEMA TC 2 and UL 651, with matching fittings complying with NEMA TC 3 by same manufacturer as duct.

B. Subject to compliance with requirements, available Manufacturers offering products that may be incorporated into the work include, but are not limited to the following:

1. Carlon

2. National Pipe & Plastics

3. OMNI

C. Listed and labeled as defined in NFPA 70, by a nationally recognized testing laboratory, and marked for intended location and application.

D. Solvents and Adhesives: As recommended by conduit manufacturer.

2.3 FLEXIBLE NONMETALLIC DUCTS

A. HDPE Duct: Type EPEC-40 HDPE complying with NEMA TC 7 and UL 651A.

1. Subject to compliance with requirements, available Manufacturers offering products that may be incorporated into the work include, but are not limited to the following:

a. ARNCO Corp.

b. Carlon

c. National Pipe & Plastics

d. OMNI

e. Premiere Conduit

2. Listed and labeled as defined in NFPA 70, by a nationally recognized testing laboratory, and marked for intended location and application.

2.4 DUCT ACCESSORIES

A. Duct Spacers: Factory-fabricated, rigid, PVC interlocking spacers; sized for type and size of duct with which used, and selected to provide minimum duct spacing indicated while supporting duct during concreting or backfilling. Include hold down bars that secure duct bank in place to prevent duct flotation.

1. Subject to compliance with requirements, available Manufacturers offering products that may be incorporated into the work include, but are not limited to the following:

a. Allied Tube & Conduit

b. Pantexinc

UNDERGROUND DUCTS AND RACEWAYS FOR ELECTRICAL SYSTEMS 260543 - 4

c. Carlon

d. PENCEL Plastics

e. Underground Devices Inc.

B. Detectable Underground-Line Warning Tape: Acid- and alkali-resistant, polyester encased B- 721 aluminum foil warning tape manufactured for marking and identifying underground utilities, 2 inches (50.8 mm) wide and 5 mils (0.127 mm) thick, continuously inscribed with sub-surface black lettering on color field noted below, with a description of the utility; colored as follows:

1. Red: CAUTION BURIED ELECTRIC LINE BELOW.

2. Orange: CAUTION BURIED FIBER OPTIC or TELEPHONE LINE BELOW.

PART 3 - EXECUTION

3.1 PREPARATION

A. Coordinate layout and installation of duct, duct bank, manholes, handholes, and boxes with final arrangement of other utilities, site grading, and surface features as determined in the field.

Notify Architect if there is a conflict between areas of excavation and existing structures or archaeological sites to remain.

B. Coordinate elevations of duct and duct-bank entrances into manholes, handholes, and boxes with final locations and profiles of duct and duct banks, as determined by coordination with other utilities, underground obstructions, and surface features. Revise locations and elevations as required to suit field conditions and to ensure that duct and duct bank will drain to manholes and handholes, and as approved by Architect.

C. Clear and grub vegetation to be removed, and protect vegetation to remain according to Specification Section "Site Clearing." Remove and stockpile topsoil for reapplication according to Specification Section "Site Clearing."

3.2 UNDERGROUND DUCT APPLICATION

A. Duct for Electrical Feeders 600 V and Less: Type EPC-40-PVC RNC, direct-buried unless otherwise indicated.

B. Duct for Electrical Branch Circuits: Type EPC-40-PVC RNC, direct-buried unless otherwise indicated.

C. Underground Ducts Crossing Paved Paths and Walks: Type EPC-40 PVC RNC, encased in reinforced concrete.

UNDERGROUND DUCTS AND RACEWAYS FOR ELECTRICAL SYSTEMS 260543 - 5

3.3 EARTHWORK

A. Excavation and Backfill: Comply with Specification Section "Earth Moving," but do not use heavy-duty, hydraulic-operated, compaction equipment.

B. Restoration: Replace area after construction vehicle traffic in immediate area is complete.

C. Restore surface features at areas disturbed by excavation, and re-establish original grades unless otherwise indicated. Replace removed sod immediately after backfilling is completed.

D. Restore areas disturbed by trenching, storing of dirt, cable laying, and other work. Restore vegetation and include necessary topsoiling, fertilizing, liming, seeding, sodding, sprigging, and mulching to return to existing condition with approval by Architect/Engineer.

E. Cut and patch to existing condition, pavement in the path of underground duct, duct bank, and underground structures.

3.4 DUCT AND DUCT-BANK INSTALLATION

A. Where indicated on Drawings, install duct, spacers, and accessories into the duct-bank configuration shown. Duct installation requirements in this Section also apply to duct bank.

B. Install duct according to NEMA TCB 2.

C. Slope: Pitch duct a minimum slope of 1:300 down toward manholes and handholes and away from buildings and equipment. Slope duct from a high point between two manholes, to drain in both directions.

D. Curves and Bends: Use 5-degree angle couplings for small changes in direction. Use manufactured long sweep bends with a minimum radius of 48 inches, both horizontally and vertically, at other locations unless otherwise indicated.

1. Duct shall have maximum of four 90 degree bends or the total of all bends shall be no more 360 degrees between pull points.

E. Joints: Use solvent-cemented joints in duct and fittings and make watertight according to manufacturer's written instructions. Stagger couplings so those of adjacent duct do not lie in same plane.

F. Installation Adjacent to High-Temperature Steam Lines: Where duct is installed parallel to underground steam lines, maintain minimum of 10 feet separation between ductbank and steamlines. Where the duct crosses above an underground steam line, install insulation blankets listed for direct burial to isolate the duct bank from the steam line.

G. End Bell Entrances to Manholes and Concrete and Polymer Concrete Handholes: Use end bells, spaced approximately 10 inches o.c. for 5-inch duct, and vary proportionately for other duct sizes.

1. Begin change from regular spacing to end-bell spacing 10 feet from the end bell, without reducing duct slope and without forming a trap in the line.

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2. Expansion and Deflection Fittings: Install an expansion and deflection fitting in each duct in the area of disturbed earth adjacent to manhole or handhole. Install an expansion fitting near the center of all straight line direct-buried duct with calculated expansion of more than 3/4 inch.

3. Grout end bells into structure walls from both sides to provide watertight entrances.

H. Terminator Entrances to Manholes and Concrete and Polymer Concrete Handholes: Use manufactured, cast-in-place duct terminators, with entrances into structure spaced approximately 6 inches o.c. for 4-inch duct, and vary proportionately for other duct sizes.

1. Begin change from regular spacing to terminator spacing 10 feet from the terminator, without reducing duct line slope and without forming a trap in the line.

2. Expansion and Deflection Fittings: Install an expansion and deflection fitting in each duct in the area of disturbed earth adjacent to manhole or handhole. Install an expansion fitting near the center of all straight line duct with calculated expansion of more than 3/4 inch.

I. Building Wall Penetrations: Make a transition from underground duct to GRC at least 10 feet outside the building wall, without reducing duct line slope away from the building and without forming a trap in the line. Use fittings manufactured for RNC-to-GRC transition. Install GRC penetrations of building walls as specified in Section 260544 "Sleeves and Sleeve Seals for Electrical Raceways and Cabling."

J. Sealing: Provide temporary closure at terminations of duct with pulled cables. Seal spare duct at terminations. Use sealing compound and plugs to withstand at least 15-psig hydrostatic pressure.

K. Pulling Cord: Install 200-lbf-test nylon cord in empty ducts.

L. Direct-Buried Duct and Duct Bank:

1. Excavate trench bottom to provide firm and uniform support for duct. Comply with requirements in Specification Section "Earth Moving" for preparation of trench bottoms for pipes less than 6 inches in nominal diameter.

2. Depth: Install top of duct at least 36 inches below finished grade unless otherwise indicated.

3. Set elevation of bottom of duct bank below frost line.

4. Support ducts on duct spacers coordinated with duct size, duct spacing, and outdoor temperature.

5. Spacer Installation: Place spacers close enough to prevent sagging and deforming of duct, with not less than five spacers per 20 feet of duct. Place spacers within 24 inches of duct ends. Stagger spacers approximately 6 inches between tiers. Secure spacers to earth and to ducts to prevent floating during concreting. Tie entire assembly together using fabric straps; do not use tie wires or reinforcing steel that may form conductive or magnetic loops around ducts or duct groups.

6. Install manufactured GRC elbows for stub-ups and at building entrances unless otherwise indicated.

a. Couple RNC duct to GRC with adapters designed for this purpose, and encase coupling with 3 inches of concrete.

UNDERGROUND DUCTS AND RACEWAYS FOR ELECTRICAL SYSTEMS 260543 - 7

7. After installing first tier of duct, backfill and compact. Start at tie-in point and work toward end of duct run, leaving ducts at end of run free to move with expansion and contraction as temperature changes during this process. Repeat procedure after placing each tier. After placing last tier, hand place backfill to 4 inches over duct and hand tamp.

Firmly tamp backfill around ducts to provide maximum supporting strength. Use hand tamper only. After placing controlled backfill over final tier, make final duct connections at end of run and complete backfilling with normal compaction. Comply with requirements in Specification Section "Earth Moving" for installation of backfill materials.

a. For direct buried duct, place minimum 3 inches of sand as a bed for duct. Place sand to a minimum of 6 inches above top level of duct.

M. Detectable Underground-Line Warning Tape: Bury underground line no less than 12 inches above and 4 inches to 6 inches below surface for maximum detectability, all concrete-encased and direct buried duct and duct banks. Align tape parallel to and within 3 inches of centerline of duct bank. Provide an additional warning tape for each 12-inch increment of duct-bank width over a nominal 18 inches. Space additional tapes 12 inches apart, horizontally.

N. Seal all conduits at the last structure prior to conduits entering a building and where conduits enter a building with Carlon “MAT” or “MAQ” series duct plug for conduits with wires and Carlon “MAE” series for spare conduits or equal. All spare conduits shall have nylon pull string and footage tape. Provide brass tag at each end of conduit indicating other end locations and overall footage of conduit. Provide brass tag at each end of conduit indicating other end location and overall footage of conduit.

3.5 GROUNDING

A. Ground underground ducts and utility structures according to Specification Section "Grounding and Bonding for Electrical Systems."

3.6 FIELD QUALITY CONTROL

A. Perform the following tests and inspections:

1. Demonstrate capability and compliance with requirements on completion of installation of underground duct, duct bank, and utility structures.

2. Pull solid aluminum or wood test mandrel through duct to prove joint integrity and adequate bend radii, and test for out-of-round duct. Provide a minimum 12-inch-long mandrel equal to duct size minus 1/4 inch. If obstructions are indicated, remove obstructions and retest.

3. Test manhole and handhole grounding to ensure electrical continuity of grounding and bonding connections. Measure and report ground resistance as specified in Specification Section "Grounding and Bonding for Electrical Systems."

B. Correct deficiencies and retest as specified above to demonstrate compliance.

C. Prepare test and inspection reports.

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3.7 CLEANING

A. Pull leather-washer-type duct cleaner, with graduated washer sizes, through full length of duct until duct cleaner indicates that duct is clear of dirt and debris. Follow with rubber duct swab for final cleaning and to assist in spreading lubricant throughout ducts.

B. Clean internal surfaces of manholes, including sump.

1. Sweep floor, removing dirt and debris.

2. Remove foreign material.

END OF SECTION

B. Ground Water: Assume ground-water level is at grade level unless a lower water table is noted on Drawings.

2. Listed and labeled as defined in NFPA 70, by a nationally recognized testing laboratory, and marked for intended location and application.

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