CONSTRUCTION STANDARD SPECIFICATION

SECTION 02584

U[UNDERGROUND DUCTS AND UTILITY STRUCTURES]{.underline}

U[Page]{.underline}

PART 1 - GENERAL

1.01 Summary [3](#summary)

1.02 References [4](#references)

1.03 Submittals [4](#submittals)

PART 2 - PRODUCTS

2.01 General [5](#general)

2.02 Conduit And Duct Systems - General
[5](#conduit-and-duct-systems---general)

2.03 Metallic Conduit - General [5](#metallic-conduit---general)

2.04 Rigid Metal Conduit And Fittings
[5](#rigid-metal-conduit-and-fittings)

2.05 Intermediate Metal Conduit (Imc) And Fittings
[6](#intermediate-metal-conduit-imc-and-fittings)

2.06 Non-Metallic Conduit - Concrete Encased
[6](#non-metallic-conduit---concrete-encased)

2.07 Corrosion Protection [6](#corrosion-protection)

2.08 Manholes - General [6](#manholes---general)

2.09 Manholes - Precast Concrete [7](#manholes---precast-concrete)

2.10 Manholes - Concrete Cast-In-Place
[7](#manholes---concrete-cast-in-place)

2.11 Manhole Accessories [8](#manhole-accessories)

PART 3 - EXECUTION

3.01 Conduits - General [8](#conduits---general)

3.02 Concrete Encased Conduits [10](#concrete-encased-conduits)

3.03 Manholes - Precast Concrete [10](#manholes---precast-concrete-1)

3.04 Manholes - Cast-In-Place Concrete
[11](#manholes---cast-in-place-concrete)

3.05 Manhole Accessories [11](#manhole-accessories-1)

3.06 Manhole And Pull Box Concrete Collars
[11](#manhole-and-pull-box-concrete-collars)

CONSTRUCTION STANDARD SPECIFICATION

SECTION 02584

U[UNDERGROUND DUCTS AND UTILITY STRUCTURES]{.underline}

# UPART 1 - GENERAL

## 1.01 SUMMARY

A. This specification covers the following items and accessory materials
associated with these items:

1.  Ducts in direct-buried duct banks.

2.  Ducts in concrete-encased duct banks.

3.  Manholes and manhole accessories.

B. Related Sections include the following:

1\. Section 01330 -- Submittal Procedures

2\. Section 02200 - Earthwork.

3\. Section 02510 - Asphalt Concrete Pavement

4\. Section 03300 - Cast-In-Place Concrete

5\. Section 16124 - Medium Voltage Cables

6\. Section 16272 - Pad Mounted Transformers

7\. Section 16310 -- 15kV Metal-Enclosed Stand-Up or Padmounted
Switchgear

8\. Section 16475 - Primary System Safety Requirements

## 1.02 REFERENCES

## The current editions of the referenced standards are a part of this specification. {#the-current-editions-of-the-referenced-standards-are-a-part-of-this-specification. .unnumbered}

A. General

1\. ANSI/NFPA 70 - National Electrical Code.

2\. ANSI/IEEE C2 - National Electrical Safety Code.

3\. ASTM C33 - Standard Specification for Concrete Aggregates.

B. Conduit

1\. NEMA C80.1 - Specification for Rigid Steel Conduit, Zinc Coated.

2\. UL 1242 and NEMA C80.6 - Intermediate Metal Conduit.

3\. NEMA RN 1 - Polyvinyl Chloride (PVC) Externally Coated Galvanized
Rigid Steel Conduit and Intermediate Metal Conduit.

4\. NEMA TC 2 -- Electrical Polyvinyl Chloride (PVC) Tubing and Conduit

5\. ANSI/NEMA FB 1 - Fittings, Cast Metal Boxes, and Conduit Bodies for
Conduit, Electrical Metallic Tubing and Cable.

6\. NEMA TC 3 - PVC Fittings for Use With Rigid PVC Conduit and Tubing.

C. Manholes

1\. AASHTO - Standard Specification for Highway Bridges.

2\. ANSI/ASTM A153 -- Standard Specification for Zinc Coating (Hot-Dip)
on Iron and Steel Hardware.

3\. ANSI/ASTM A659 -- Standard Specification for Commercial Steel (CS),
Sheet and Strip, Carbon (0.16 Maximum to 0.25 Maximum Percent),
Hot-Rolled.

4\. ASTM A48 -- Standard Specification for Gray Iron Castings.

5\. ASTM A123 -- Standard Specification for Zinc (Hot-Galvanized)
Coatings on Iron and Steel Products.

## 1.03 SUBMITTALS

## The Contractor shall submit catalog data as required per Sandia\'s Standard Specification, Section 01330, "Submittal Procedures". {#the-contractor-shall-submit-catalog-data-as-required-per-sandias-standard-specification-section-01330-submittal-procedures. .unnumbered}

# UPART 2 - PRODUCTS

## 2.01 GENERAL

## All materials shall be new and applicable as listed, labeled, or approved by the Underwriters\' Laboratories, Inc. Defective equipment or equipment damaged in the course of installation or test shall be replaced or repaired in an approved manner. {#all-materials-shall-be-new-and-applicable-as-listed-labeled-or-approved-by-the-underwriters-laboratories-inc.-defective-equipment-or-equipment-damaged-in-the-course-of-installation-or-test-shall-be-replaced-or-repaired-in-an-approved-manner. .unnumbered}

## 2.02 CONDUIT AND DUCT SYSTEMS - GENERAL

## Conduit and duct systems shall be of the type specified in the drawings and shall meet the requirements herein. {#conduit-and-duct-systems-shall-be-of-the-type-specified-in-the-drawings-and-shall-meet-the-requirements-herein. .unnumbered}

A. Conduits shall be joined in such a way as to prevent solid matter
from entering the joints. Joints shall form a continuous smooth interior
surface between joining conduit sections so that cable will not be
damaged when pulled past the joint.

B. Conduit installed on bridges, building roofs, or high temperature
areas shall incorporate expansion joints. Metallic conduit on a bridge
shall be grounded.

C. Pull boxes shall be \"FL\" style box assemblies of Fibrelyte
composite materials as manufactured by Christy Concrete products or
approved equal, unless otherwise noted on drawings. Material compressive
strength shall not be less than 11,000 PSI. Covers shall be bolted-down
using penta head bolts, heavy duty to meet AASHTO H20 traffic load and
logo as indicated. Boxes shall be stackable for extra depth. Dimensions
of pull boxes shall be as specified on drawings.

D. Communication conduit for fiber optic cable shall have high capacity
flexible multiple channel innerduct manufactured by FO-DUCT or as
specified on contract drawings. The number of channels shall be
specified on the contract drawings.

## 2.03 METALLIC CONDUIT - GENERAL

A. All steel conduits, RGS or IMC, in direct contact with the earth
shall receive a protective covering that is mechanically applied in a
factory or field plant especially equipped for this purpose. (Ref. Part
2.07)

B. No conduit shall be covered with backfill until after the approval of
the Sandia Delegated Representative is obtained.

## 2.04 RIGID METAL CONDUIT AND FITTINGS

A. Rigid steel conduit: ANSI C80.1.

B. PVC externally coated conduit: NEMA.RN 1; rigid steel conduit with
external 20-mil PVC coating and internal galvanized surface.

C. Fittings and conduit bodies: ANSI/NEMA FB 1; threaded type, material
to match conduit.

## 2.05 INTERMEDIATE METAL CONDUIT (IMC) AND FITTINGS

A. Galvanized steel conduit: UL 1242 and ANSI C80.6.

B. PVC externally coated conduit: NEMA.RN 1; intermediate metal conduit
with external 20-mil PVC coating and internal galvanized surface.

C. Fittings and conduit bodies: ANSI/NEMA FB 1; use fittings and conduit
bodies specified above for rigid steel conduit.

## 2.06 NON-METALLIC CONDUIT - CONCRETE ENCASED

A. Conduit: NEMA TC 2; Schedule 40 PVC or Schedule 80 PVC as indicated
on the drawings.

B. Fittings and conduit bodies: NEMA TC 3.

C.  The concrete for the duct envelope shall conform in quality to all
    requirements for placing and curing as described in the concrete
    specifications. No concrete shall be poured until inspection is
    obtained. Backfilling shall not be started until the concrete has
    set for 5 hours.

D.  No duct shall be covered with backfill until approval is obtained.

E. For vertical stub-ups, horizontal bends, and any off-sets greater
than 22° in primary electrical and communication underground conduit
runs, use PVC-coated rigid steel or IMC factory bends. For electrical
conduits, the minimum radius shall be 24 inches for 3 inches and smaller
conduit and 36 inches radius for conduit larger than 3 inches, unless
noted otherwise on the drawings. For communication conduits, the minimum
radius shall be 48" for 4" conduit and a 60" radius for 5" conduit,
unless noted otherwise on the drawings. Half-lapped application of
corrosion protection tape is an acceptable alternate to PVC coating.
Standard radius conduit can be used for secondary electrical conduit as
specified on drawings.

## 2.07 CORROSION PROTECTION

A. One of the following methods shall be used for metal conduit below
grade:

1\. 3M Scotchwrap 51, 20 mils thick used in conjunction with 3M
Scotchwrap Pipe Primer applied as recommended by manufacturer.

2\. Factory coated PVC on rigid conduit.

## 2.08 MANHOLES - GENERAL

A. Manholes can be either precast concrete or cast-in-place as
designated on the drawings.

B. Drainage shall be provided to keep the manholes free of water during
construction.

## 

## 2.09 MANHOLES - PRECAST CONCRETE

A. Manufacturer shall have documented experience in the manufacture of
manholes for a minimum of three years.

B. Base course material shall be sand, 3 inches minimum compacted 95%.

C. Precast concrete: Air-entrained, 4,000 psi minimum compressive
strength at 28 days.

D. Reinforcing: AASHTO HS-20; bridge loading.

E. Manhole Shape: As indicated on drawings.

F. Inside Dimensions: As indicated on drawings.

G. Wall Thickness: AASHTO HS-20; bridge loading.

H. Include 40-inch diameter grooved opening in top section for frame and
cover for power manholes and 36-inch diameter grooved opening for
communication manholes.

I. Frame and Cover Sections: 36-inch diameter clear opening for power
manholes and 30-inch diameter for communication manholes.

J. Include one 12-inch drain opening and two 1-inch ground rod openings
in base, one each diagonally opposite corners, not less than 6 inches or
greater than 12 inches from the wall.

K. Window for Duct Entry: Unless otherwise specified on drawings, 9-6
inch knockouts 3 rows of three on 8.56 inch centers shall be provided on
each wall with top row of knockouts not less than two feet below top of
manhole. Refer to contract drawings for specific construction details.

L. Include cable-pulling irons opposite each duct entry.

M. Include inserts for cable racks on three-foot centers.

N. Include metal ladder in manhole, steps at 16 inches on center, ladder
bolted to manhole neck.

O. Ram-Nek, Kent Seal or approved equal sealants shall be used to seal
the joints in this manhole.

## 2.10 MANHOLES - CONCRETE CAST-IN-PLACE

A. All provisions of Parts 2.9 and 2.11 unless specified in this part.

B. Concrete: 3,000 psi minimum compressive strength at 28 days in
conformance with requirements of Section 03300, "Cast-In-Place
Concrete".

C. Provide reinforcing under the provisions of Section 03300,
"Cast-In-Place Concrete".

## 2.11 MANHOLE ACCESSORIES

A. Manhole Frames and Covers: ASTM A48; Class 30B gray cast iron,
machine finished with flat bearing surfaces. Covers shall be round and
have \"Electric\" or \"Signal\" as designated on plans and \"SNLA\" in
permanent lettering.

B. Sump Covers: ASTM A48; Class 30B gray cast iron.

C. Pulling Irons: 7/8 inch diameter steel bar forming a triangle of 9
inches per side when set. Galvanize to ANSI/ASTM A153 for irregular
shaped articles. Locate opposite each duct entry.

D. Cable Rack Inserts: Steel channel insert with minimum load rating of
800 pounds, length to match cable rack channel. Locate 3 feet on center.

E. Cable Rack Channel: 1-1/2 x 3/4 inch steel channel wall bracket, 48
inch length, with cable rack arm mounting slots on 1-1/2 inch centers.

F. Cable Racks: ANSI/ASTM A659; steel channel, 1-1/2 x 3/4 x 14 inches
with fiberglass reinforced polyester or porcelain cable supports and
fastener to match mounting channel.

G. Manhole Ladder: Cast iron, suitable for manhole shape and
construction, and hot dip galvanized.

I. Ground Rods: 3/4\" x 10\' Copperweld.

J. Grade Rings: Pre-cast concrete (4000 psi. minimum compressive
strength at 28 days) with inside diameter equivalent to manhole opening
specified in Part 2.9H. The ring shall have circumferential rebar #3
minimum with a trowel finish to provide a true plane within 1/8 inch, as
determined with a 5-ft straight edge.

# UPART 3 - EXECUTION

## 3.01 CONDUITS - GENERAL

A. Where underground crossings are known, field verify horizontal and
vertical locations prior to excavation and placement of conduit. Notify
the SDR of any deviations to the drawings. Any profile changes and
existing utility line crossings are to be as built on drawings showing:
type of line, size, and depth below the surface.

B.  Install at 36" minimum depth of burial to top of electrical ductbank
    (top of concrete), unless otherwise noted in drawing..

C. Spacers shall be used where more than one duct is installed and shall
be the standard product of the duct manufacturer for the type and size
duct. They shall be located at five-foot intervals, secured to the ducts
with #16 gage iron wire. The spacers shall be securely anchored every
ten (10) feet to the bottom of the trench to prevent ducts from floating
during concrete pouring. Unless otherwise noted on drawings, 4\" conduit
shall have an approximately 7.5 inch spacing center-to-center, both
horizontally and vertically; 5\" conduit shall have an approximate 8.56
inch spacing center-to-center.

D. Preparation and placing of concrete shall be in accordance with
provisions of section 03300, "Cast-In-Place Concrete." Concrete mix
design shall be a minimum of 3000 psi with ¾" aggregate and 6" slump.
Mechanical vibration shall be used in the placement. The top of concrete
encasement shall be smooth finish accomplished by mechanical vibrator,
spading, and/or adding water to the delivered concrete.

E. Terminate conduits in an end bell at manhole and building foundation
penetrations. Stub-ups of rigid or IMC duct in equipment pads shall have
insulated grounding bushings.

F. Apply corrosion protection tape, half lapped, to non-PVC-coated
underground metallic conduit and fittings that are in direct contact
with earth only.

G. Conduit and duct runs shall be short, straight runs between points of
the system.

H. Duct runs shall be graded to drain toward one or both terminal points
of the duct run. The slope shall not be less than 2 inches for every 100
ft. of length, unless otherwise shown on contract drawings.

I. Conduits and duct runs shall be installed on compacted soil when
entering a manhole, building foundation, crossing a road, railroad
track, or bridge abutment to prevent shear stress on the conduit.

J. All paving and concrete cuts shall be made with a concrete saw. All
surfaces to be replaced shall match existing and shall be in accordance
with applicable concrete of asphalt specifications.

K. Conduit penetrations into buildings or through above ground
foundations, shall be sealed with duct seal or conduit sealer to prevent
gas or water entry.

L. Trenching and backfilling shall be in accordance with Section 02200,
"Earthwork".

M. Wires, cables, or other conductors shall be pulled into the duct as
shown on the drawings. Empty ducts shall have a 1/4\" polypropylene rope
provided with 2 feet of slack at each end with both ends secured.

N. When multiple channel innerducts (FO-DUCT) are pulled through
conduit, secure every 10-ft section so as to prevent rolling of channels
within conduit. Leave one-foot ends protruding from face of manhole.

O.  Conduit or duct banks shall maintain 1 foot vertical and 1 foot
    horizontal separation from other utility lines where possible, with
    the exception being a steam line crossing. A separation of 30" above
    steam lines and 24" below steam lines shall be maintained. If 6" of
    foamglass insulation is applied on the existing steam line, then the
    minimum separation can be reduced to 24" above steam lines and 18"
    below steam lines. In all cases, the separation should be measured
    from the existing outer casing of the steam pipe or the outer
    surface of the existing pipe insulation. Where foamglass insulation
    is required, it should be installed immediately around the steam
    main, extending a minimum of 3 feet each side from the crossing.
    Foamglass insulation is not required around steam condensate piping

P. A warning tape shall be installed one foot above duct. The warning
tape shall be of inert plastic film 4 mils thick specifically formulated
for prolonged use underground, resistant to alkalis and acids found in
soil. It shall have a tensile strength of 30 pounds per 3 inch wide
strip. The tape shall bear a continuous printed message repeated every
36 inches. The tape shall be Terra Tape Standard 250 manufactured by
Reef Industries, Inc., or approved equal. The tape shall be colored in
accordance with American Public Works Association (APWA) recommended
color code for marking buried lines of all types. Current recommended
colors are Red for power lines and Orange for telephone/signal.

Q. Where above grade marking of underground utilities is indicated on
drawings, the marking shall be in accordance with Standard Drawing
WU5006STD "Utility Marker for Buried Pipe and Cable" (see Attachment A).

R.  Swab Duct: Use suitable caps to protect installed duct against
    entrance of dirt and moisture.

S.  Duct bank crossing streets with less than 2' 6" of earth cover
    should be reinforced with 4-#4 rebar equally spaced at the bottom of
    the duct bank.

T.  A 4/0 stranded bare copper ground wire shall be installed in the
    bottom of the duct bank and between manholes. The 4/0 ground is to
    be connected to the 4/0 ground bus in the manhole with an exothermic
    connection or approved UL mechanical connector.

## 3.02 CONCRETE ENCASED CONDUITS

A. Provide minimum three inch concrete cover at bottom, four inch at
top, and minimum of four to a maximum of six inch cover at sides of
conduit or ductbank.

B. A mandrel 1/4\" - 3/8\" smaller than the conduit shall be pulled
through each conduit. A circular wire brush the same diameter of the
conduit shall be pulled through the conduit.

C. Conduit stub outs shall be RGS or IMC capped and not encased in
concrete for future accessibility. Capping shall prevent moisture or
debris from entering the duct system.

## 3.03 MANHOLES - PRECAST CONCRETE

A. Excavate, install base material, and compact base material. Compact
to 95% density or as required by manufacturer.

B. Install, seal, and waterproof precast sections in accordance with
manufacturer\'s instructions.

C. Use precast grade ring sections to bring manhole entrance to proper
elevation.

D. Install manholes plumb.

E. Set the top of each manhole to finished elevation.

## 3.04 MANHOLES - CAST-IN-PLACE CONCRETE

A. Form cast-in-place manholes, inside and outside surfaces, in
accordance with provisions of Section 03300, "Cast-In-Place Concrete".

B. Manhole Shape: As indicated on drawings.

C. Inside Dimensions: As indicated on drawings.

D. Wall Thickness: As indicated on drawings.

E. Form window for duct entry as indicated on plans.

F. Include 12 inch drain opening and two 1-inch ground rod openings in
base section.

G. Cast cable-pulling irons in place opposite each duct entry window.

H. Cast inserts for cable racks in place at three foot centers.

## 3.05 MANHOLE ACCESSORIES

A. Where manhole drainage is into sewers, suitable traps shall be
provided to prevent entrance of sewer gas into manholes and duct
systems.

B. Install 2 ground rods with top protruding 4 inches above manhole
floor. Connect ground rods with 4/0 bare copper run around perimeter of
inside manhole at floor. Copper conductor connection to ground rod to be
exothermic, or UL listed mechanical connection.

C. Attach cable racks to inserts after manhole construction is complete.

## 3.06 MANHOLE AND PULL BOX CONCRETE COLLARS

A.  Install a one foot wide concrete (3,000 psi, 3/4-inch aggregate)
    collar around the manhole or pull box cover, unless noted otherwise
    on drawings.

B.  As a minimum the height of the concrete collar should go from the
    top of the manhole or pull box cover to eight inches below grade.

C.  The top of the concrete collar shall slope down away from the cover
    so that no water will accumulate around the cover.

END OF SECTION