1 Scope
NOTE This specification covers the furnishing and installation of complete underground duct bank systems — concrete-encased and direct-buried conduit raceways — used to distribute electrical power and communications between buildings, transformers, substations, switchgear, generators, site lighting, and exterior equipment. (1.1)
NOTE The work includes the conduit, the concrete encasement and any reinforcing steel, the duct spacers, the excavation and bedding, the backfill, the cover and separation from grade and other utilities, the building and structure entries and their seals, the warning tape and marking, and the proving of every duct before cables are pulled. (1.2)
NOTE The duct bank establishes the buried raceway pathway; the conductors and cables installed within it are specified separately in
Conductors And Cables.
(1.3) NOTE The manholes, handholes, and pull boxes that interconnect duct bank segments are specified in this standard at the interface to the duct bank, and their precast structures are coordinated with the structural and civil drawings. (1.4)
NOTE Grounding and bonding of the duct bank, its conduits, and its structures is coordinated with
Grounding And Bonding.
(1.5) 1.6 All duct bank materials and installation shall comply with NFPA 70 (National Electrical Code), the applicable building and civil codes, and the requirements of the authority having jurisdiction and the serving utility.
1.7 All conduit, fittings, and accessories shall be listed and labeled by a Nationally Recognized Testing Laboratory (NRTL) for direct burial or concrete encasement as applicable to the installation.
1.8 Where a referenced standard and the NEC conflict, the more stringent requirement shall govern unless the Engineer directs otherwise in writing.
NOTE Where the serving utility has its own duct bank standard for the service-entrance pathway, the utility standard shall govern that portion of the work. (1.9)
2 Referenced Standards
2.1 Materials and installation shall comply with the latest adopted edition of the following standards and codes in effect at the time of bid, except where the contract documents specify a particular edition.
2.2 Where conflicts exist between referenced standards, the more stringent requirement shall govern unless otherwise directed by the Engineer of Record.
| Standard |
Title |
| NFPA 70 |
National Electrical Code (Article 300.5 underground installations and minimum cover, 305.15 / 310.15 conductor ampacity and adjustment, Article 352 rigid PVC conduit, Article 354 RTRC, Article 356 LFNC) |
| NFPA 70E |
Standard for Electrical Safety in the Workplace |
| UL 651 |
Schedule 40, 80, Type EB and A Rigid PVC Conduit and Fittings |
| UL 6 |
Electrical Rigid Metal Conduit — Steel |
| UL 1242 |
Electrical Intermediate Metal Conduit — Steel |
| UL 1684 |
Reinforced Thermosetting Resin Conduit (RTRC) and Fittings |
| NEMA TC 2 |
Electrical Polyvinyl Chloride (PVC) Conduit |
| NEMA TC 3 |
PVC Fittings for Use with Rigid PVC Conduit and Tubing |
| NEMA TC 6 & 8 |
PVC Plastic Utilities Duct for Underground Installation |
| NEMA TC 9 |
Fittings for PVC Plastic Utilities Duct for Underground Installation |
| ASTM F512 |
Smooth-Wall PVC Conduit and Fittings for Underground Installation |
| ASTM C94 / C94M |
Ready-Mixed Concrete |
| ASTM C150 |
Portland Cement |
| ASTM A615 / A615M |
Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement |
| ACI 318 |
Building Code Requirements for Structural Concrete |
| ASTM C858 |
Underground Precast Concrete Utility Structures |
| ASTM C857 |
Minimum Structural Design Loading for Underground Precast Concrete Utility Structures |
| SCTE 77 |
Specification for Underground Enclosure Integrity (non-concrete handholes and boxes) |
| IEEE 525 |
Guide for the Design and Installation of Cable Systems in Substations |
| IEEE 835 |
Standard Power Cable Ampacity Tables |
| IEEE 422 |
Guide for the Design and Installation of Cable Systems in Power Generating Stations |
| NECA 1 |
Standard for Good Workmanship in Electrical Construction |
3 Submittals
3.1 Action Submittals
3.1.1 The Contractor shall submit the following for the Engineer's review and approval prior to ordering materials or beginning excavation:
- Product data for the conduit, fittings, duct spacers, end bells, reducers, and all accessories proposed for the duct bank, identifying the manufacturer, type designation, material, wall thickness, and listing
- Duct bank cross-sections and plan-and-profile drawings showing the duct configuration, the number and arrangement of ducts, the spare-duct allocation, the concrete envelope dimensions and cover, the reinforcing steel where required, the spacer type and spacing, and the routing and slope
- Concrete mix design conforming to the specified compressive strength, including the red coloring admixture dosage where pigmented concrete is required
- Reinforcing steel shop drawings and bar schedules where the duct bank is reinforced
- Cable ampacity and duct bank heating calculations (Neher-McGrath / IEEE 835) for the as-designed configuration, using the design soil thermal resistivity, where the duct bank serves feeders whose ampacity depends on the burial configuration
- Product data for precast or cast-in-place manholes and handholes, including the structural design loading and the SCTE 77 tier or ASTM C858 design basis
☑ Conduit, fitting, spacer, and accessory product data
☐ Duct bank cross-sections and plan-and-profile drawings
☐ Concrete mix design (including red pigment dosage)
☐ Reinforcing steel shop drawings and bar schedule
☐ Cable ampacity / duct bank heating calculations
☐ Manhole and handhole structural and product data
3.1.2 Installation of any duct bank segment shall not proceed until the corresponding submittals are reviewed and returned.
3.2 Closeout Submittals
3.2.1 The Contractor shall provide the following at substantial completion, reflecting the installed condition where the duct bank routing or depth differs from the contract drawings, and coordinated with the project record documents:
- Record (as-built) drawings showing the actual horizontal routing, depth of cover, duct configuration, and the surveyed location of every manhole, handhole, stub-up, and direction change
- Identification of each spare and occupied duct at every structure and termination
- Mandrel and proofing records confirming that each duct passed before acceptance
- Concrete delivery tickets and compressive-strength test reports
☑ Record (as-built) routing, depth, and configuration drawings
☑ Surveyed manhole, handhole, and stub-up locations
☐ Spare and occupied duct identification records
☑ Mandrel and proofing records
☐ Concrete strength test reports and delivery tickets
4 Quality Assurance
4.1 Installer Qualifications
4.1.1 Duct bank work shall be installed by a licensed electrical contractor experienced in underground duct bank construction, coordinating the excavation, concrete, and reinforcing work with the trades performing it.
4.1.2 Installation workmanship shall meet or exceed NECA 1.
4.1.3 Concrete placement and reinforcing steel work shall be performed by trades experienced in cast-in-place concrete and shall comply with ACI 318.
4.2 Regulatory and Utility Coordination
4.2.1 The Contractor shall locate all existing underground utilities along the duct bank route before excavation and shall maintain the separation required by each utility owner.
4.2.2 The Contractor shall coordinate the service-entrance duct bank with the serving utility and shall construct that portion to the utility's standard where the utility's standard governs.
4.2.3 The duct bank trench and the installed conduit configuration shall be available for inspection by the authority having jurisdiction before concrete is placed or backfill is installed.
4.2.4 The Contractor shall not encase or backfill any duct bank segment until it has been inspected where inspection is required.
5 Environmental and Service Conditions
NOTE The performance of a duct bank — its required cover, its concrete envelope, and the ampacity of the cables it carries — depends on the soil, the water table, and the surface loading along the route. (5.1)
5.2 The following conditions shall be evaluated for the duct bank route.
5.3 Soil Thermal Resistivity
NOTE The ampacity of cables in a duct bank is governed in large part by how readily the surrounding earth conducts heat away, expressed as the soil thermal resistivity (rho); a higher rho traps heat and lowers cable ampacity. (5.3.1)
NOTE Average soil across most of the United States has a thermal resistivity near 90 °C-cm/W, damp coastal soil near 60, and dry rocky or sandy soil near 120; the duct bank heating calculation is only as good as the rho it assumes. (5.3.2)
60120
607590105120
Default: 90 °C-cm/W
Per drawings — geotechnical report
5.3.3 The Engineer shall establish the design soil thermal resistivity from the geotechnical investigation for any duct bank whose feeder ampacity depends on the burial configuration.
5.3.4 Where the native soil thermal resistivity is high or the duct bank is heavily loaded, the Engineer shall evaluate a thermal (controlled-resistivity) backfill or a corrective fill envelope to limit the cable operating temperature.
5.4 Water Table and Drainage
NOTE A duct bank below the water table fills with water regardless of sealing, and the design shall assume the ducts will carry water; the system is sloped to drain and the cables are rated for wet locations. (5.4.1)
5.4.2 The duct bank shall be sloped to drain toward manholes, handholes, or designated low points and away from building entries.
5.4.3 Where a high water table or flotation is a concern during construction, the Contractor shall dewater the trench as required to place the concrete and shall restrain the conduit assembly against flotation before and during the pour.
5.5 Surface Loading
5.5.1 The depth of cover and the concrete envelope shall account for the surface loading over the route — open landscape, pedestrian areas, parking, driveways, and roadways each impose a different load and a different minimum cover.
☑ Open landscape / non-traffic earth
☐ Pedestrian walkways and plazas
☐ Parking areas and driveways
☐ Public roadways and heavy vehicular traffic
☐ Under building slab
6 Duct Bank Configuration
NOTE A duct bank is a planned array of parallel conduits installed at a fixed spacing, either encased in a monolithic concrete envelope or directly buried in earth or controlled fill. (6.1)
NOTE The choice between concrete encasement and direct burial, the number and arrangement of ducts, and the spare-duct allocation are the configuration decisions made before any field work. (6.2)
6.3 Encased Versus Direct-Buried
NOTE A concrete-encased duct bank gives the conduits mechanical protection, fixes their spacing permanently, allows shallower cover under the NEC, and is the standard for primary feeders, service entrances, and crossings under roadways. (6.3.1)
NOTE A direct-buried conduit run is faster and less costly and is suitable for secondary feeders, site lighting, and communications where the additional protection and the fixed thermal geometry of concrete are not required. (6.3.2)
● Concrete-encased (primary feeders, service entrance, roadway crossings)
○ Direct-buried conduit (secondary feeders, lighting, communications)
○ Concrete-encased under traffic, direct-buried elsewhere on the run
6.3.3 Power feeder duct banks under roadways and in traffic-bearing areas shall be concrete-encased.
6.3.4 Where a duct bank crosses beneath a roadway, railroad, or other traffic-bearing surface, it shall be concrete-encased through the crossing regardless of the construction type used elsewhere on the run.
6.4 Number and Arrangement of Ducts
6.4.1 The number of ducts and their arrangement in rows and columns shall be as required to carry the assigned circuits plus the spare ducts, with the configuration confirmed against the contract drawings.
1 x 2 (two ducts)
2 x 2 (four ducts)
2 x 3 (six ducts)
3 x 3 (nine ducts)
3 x 4 (twelve ducts)
Per drawings — site electrical plan (deferred by default)
Per drawings — site electrical plan
6.4.2 Power circuits and communications or signal circuits shall be assigned to separate ducts.
6.4.3 Where power and communications ducts share a common concrete envelope, the communications ducts shall be separated from the power ducts by the spacing required by the NEC and the communications utility, and the Engineer shall confirm the arrangement.
6.5 Spare Ducts
NOTE Spare ducts cost little to add during construction and are prohibitively expensive to add later, so every duct bank carries spare capacity for future circuits. (6.5.1)
NOTE A spare allocation of one in four ducts (25 percent), and not fewer than one spare duct, is a common minimum for site feeder duct banks. (6.5.2)
● 25 percent spare ducts, minimum one spare
○ 33 percent spare ducts, minimum one spare
○ Spare ducts as indicated on drawings
6.5.3 The duct bank shall include spare ducts in the percentage selected, distributed across the configuration so that spares are available in each functional group.
6.5.4 Each spare duct shall be installed complete, proved with a mandrel, fitted with a pull rope, and capped at both ends.
6.5.5 Each spare duct shall be identified at every manhole, handhole, and termination.
7 Conduit Materials
NOTE Rigid PVC and the heavier-wall PVC utility ducts are the standard duct bank raceway because they are corrosion-proof, nonconductive, and economical; metal conduit is used at specific points where mechanical strength or grounding continuity is required. (7.1)
NOTE The conduit type shall be selected for the construction type: encased-burial duct for concrete-encased banks, and Schedule 40, Schedule 80, or Type A duct for direct burial. (7.2)
7.3 PVC Duct
NOTE For concrete-encased duct banks, Type EB (encased burial) PVC duct is the economical standard because the concrete provides the mechanical strength and the thinner-wall duct need only resist handling and the concrete pour. (7.3.1)
NOTE For direct-buried runs, Schedule 40 PVC is the standard wall, Type A duct is used where its thicker wall suits direct burial, and Schedule 80 is used where the conduit is subject to greater load or emerges from the ground. (7.3.2)
● Type EB (encased burial), UL 651
○ Schedule 40, UL 651 (where additional wall strength is required)
● Schedule 40, UL 651
○ Type A direct-burial duct, UL 651
○ Schedule 80, UL 651 (greater load or shallow cover)
7.3.3 Rigid PVC duct shall comply with UL 651 and NEMA TC 2, utility duct shall comply with NEMA TC 6 & 8, and fittings shall comply with NEMA TC 3 or NEMA TC 9 as applicable to the duct type.
7.3.4 PVC duct and fittings shall be rated for use with conductors operating at 90 °C.
7.3.5 Solvent-cemented joints shall be made with the cement listed for the duct, with clean, square-cut, deburred ends, staggered so that joints in adjacent ducts do not align in the same plane.
7.3.6 Where PVC duct emerges from the ground or the concrete envelope and is exposed to physical damage, the exposed portion and the elbow shall be rigid metal conduit or Schedule 80 PVC.
NOTE Rigid metal conduit and intermediate metal conduit are used for duct bank elbows under traffic, for stub-ups exposed to physical damage, and at building entries where the additional strength or a grounding path is required. (7.4.1)
7.4.2 Rigid metal conduit shall comply with UL 6 and intermediate metal conduit with UL 1242, and each shall be hot-dip galvanized and listed for the buried or encased application.
7.4.3 Large-radius elbows beneath roadways and at high-tension cable pulls shall be rigid metal conduit or factory long-radius PVC elbows of a radius that limits cable sidewall pressure.
7.4.4 Metal conduit installed in earth or in concrete shall be protected against corrosion by its galvanizing and, where the soil is corrosive, by a supplemental coating or PVC-coated conduit.
8 Concrete Encasement and Reinforcement
NOTE The concrete envelope of an encased duct bank fixes the duct geometry, protects the conduits, and forms the thermal mass that governs cable ampacity; its strength, cover, and color are all specified. (8.1)
NOTE Reinforcing steel is added where the duct bank spans soft soil, crosses other utilities, or carries surface load, and is detailed by the structural engineer. (8.2)
8.3 Concrete Mix and Cover
8.3.1 The concrete envelope shall provide a minimum of 3 in. of concrete cover over the outermost conduit on every side of the duct bank so that no conduit is closer than 3 in. to the surface of the envelope.
8.3.2 Encasement concrete shall be ready-mixed concrete conforming to ASTM C94, of the specified minimum 28-day compressive strength.
8.3.3 The concrete shall be placed so that it flows completely around and between all conduits without voids, and shall not displace the conduits or the spacers.
8.3.4 The Contractor shall place the concrete in a manner and at a rate that prevents flotation and misalignment of the conduit assembly.
8.4 Red Pigmented Concrete
NOTE Coloring the encasement concrete red marks it unmistakably as an electrical duct bank to any future excavator, reducing the risk of a dig-in; the red layer is the buried equivalent of warning tape. (8.4.1)
○ Entire encasement pigmented red
● Top portion of encasement pigmented red
○ Not required (red warning tape used instead)
8.4.2 Where red pigmented concrete is required, a red coloring admixture shall be added to the concrete at the dosage required to produce a distinct and permanent red color.
8.4.3 Where the entire envelope is not pigmented, the top portion of the encasement over the conduits shall be placed as red concrete.
8.5 Reinforcing Steel
NOTE Plain concrete encasement is adequate for most duct banks in firm, undisturbed soil; reinforcing steel is required where the duct bank spans poor soil, crosses another utility, supports surface load, or where the structural engineer directs. (8.5.1)
NOTE To limit induction heating from heavy circuits, reinforcing steel is placed only in the outer concrete envelope and is not run between the ducts. (8.5.2)
● Plain (unreinforced) concrete encasement
○ Reinforced encasement at crossings, soft soil, and surface load
○ Reinforced full length
8.5.3 Reinforcing bars shall conform to ASTM A615 and shall be detailed and placed in accordance with ACI 318 and the structural drawings.
8.5.4 Where reinforcement is provided, the reinforcing steel shall be placed in the outer concrete envelope only and shall not be run between the ducts.
8.5.5 Reinforced duct bank sections shall be provided where the duct bank crosses over another utility, spans soft or disturbed soil, or supports surface load, as detailed by the Structural Engineer.
9 Cover, Separation, and Routing
NOTE The depth of cover protects the duct bank from surface loads and excavation, and the separation from other utilities prevents both physical conflict and thermal and electrical interference; both are governed by the NEC and the utility owners. (9.1)
9.2 Depth of Cover
9.2.1 The cover over the duct bank shall comply with NEC Table 300.5 for the conduit type, circuit voltage, and surface condition, and with any greater depth required by the contract drawings or the serving utility; the more stringent value governs.
1848
182430364248
Default: 24 in
Per drawings — site electrical plan
9.2.2 A concrete-encased duct bank shall have not less than the cover required by NEC Table 300.5 measured from the top of the concrete envelope to finished grade.
9.2.3 Cover beneath roadways, driveways, and other traffic-bearing surfaces shall be the greater of the NEC requirement and the depth required by the road authority.
9.2.4 Where the required cover cannot be achieved, the Contractor shall notify the Engineer and provide concrete encasement or a structural cap as directed.
9.3 Separation Between Duct Banks
NOTE Two parallel duct banks placed too close together heat each other, and the cables in each must be derated; a centerline separation of 5 ft, or 4 ft between the concrete envelopes, is generally sufficient to avoid mutual-heating derating. (9.3.1)
9.3.2 Where two duct banks run parallel, the separation between them shall be not less than that assumed in the cable ampacity calculation.
9.3.3 Separation between parallel duct banks shall be not less than 5 ft between the closest duct centerlines, or 4 ft between the concrete envelopes, where mutual heating would otherwise require the cables to be derated.
9.4 Separation From Other Utilities
9.4.1 The duct bank shall maintain the minimum separation from water, sewer, gas, steam, and communications utilities required by the NEC and by each utility owner.
Per drawings — site utility plan
9.4.2 Where the duct bank crosses another utility, it shall cross at as near a right angle as practical and shall maintain vertical separation, with the duct bank concrete-encased or sleeved through the crossing where required.
9.4.3 Separation from steam lines and other heat sources shall be increased as required so that the assumed cable ampacity is not compromised, and the Engineer shall be consulted where a heat source parallels the route.
9.5 Routing and Slope
9.5.1 The duct bank shall be routed in straight runs between structures, with direction changes made at manholes, handholes, or with large-radius sweeps within the limit of the cable pulling tension.
9.5.2 The duct bank shall be sloped not less than 3 in. per 100 ft to drain toward manholes, handholes, or designated drainage points, and shall slope away from building and equipment entries.
9.5.3 The cumulative bend in a duct run between pull points shall not exceed 360 degrees and shall be further limited as required to keep cable pulling tension and sidewall pressure within the conductor manufacturer's limits.
10 Manholes, Handholes, and Building Entries
NOTE Manholes and handholes provide the access points where cables are pulled, spliced, and racked, and where the duct bank changes direction; building entries are where the duct bank transitions into the structure and must be sealed against water and gas. (10.1)
10.2 Manholes and Handholes
10.2.1 Manholes and handholes shall be located at the intervals required to limit cable pulling tension, at major direction changes, and at junctions, as shown on the drawings.
Precast concrete manhole (personnel-accessible)
Precast concrete handhole / pull box
Polymer-concrete handhole (SCTE 77)
Cast-in-place concrete structure
Per drawings — site electrical plan
Pedestrian / non-traffic (light duty)
Occasional non-deliberate vehicular
AASHTO H-20 / HS-20 traffic rating
Per drawings — site electrical plan (deferred by default)
10.2.2 Precast concrete manholes and handholes shall conform to ASTM C858 and the structural design loading of ASTM C857 for the traffic condition over the structure.
10.2.3 Non-concrete handholes and boxes shall be tested and rated to SCTE 77 for the tier corresponding to the traffic condition over the structure.
10.2.4 The duct bank shall enter each structure through end bells or terminating fittings that present a smooth, flared surface to the cable, and the entry shall be sealed against the concrete.
10.2.5 Each structure shall be provided with a drainage sump or a connection to drainage so that water entering the structure does not stand at the cable level.
10.2.6 Cable racks, pulling irons, and a grounding provision shall be installed in each personnel-accessible manhole, with grounding coordinated per Grounding And Bonding. 10.3 Building and Equipment Entries
NOTE A duct bank entering a building below grade is a direct path for water and soil gas into the structure, and every duct — occupied and spare — shall be sealed at the entry. (10.3.1)
10.3.2 Where the duct bank enters a building, vault, or equipment foundation, an expansion-deflection fitting shall be provided to accommodate differential settlement between the duct bank and the structure.
10.3.3 Each duct entering a building or equipment enclosure shall be sealed against the entry of water and gases with a listed duct-sealing system or expanding sealant, after the cables are installed and at every spare duct.
10.3.4 Per NEC 300.5(G), the duct bank shall be sealed where it enters a building so that moisture is not carried into the structure.
11 Installation
11.1 Excavation and Bedding
11.1.1 The trench shall be excavated to the required depth and width with a stable, uniform bottom, and shall be dewatered as required to place the conduit and concrete.
11.1.2 The trench bottom shall be graded smooth and free of rock and debris, and a bedding layer shall be provided where the native bottom is uneven or unsuitable.
11.1.3 The Contractor shall support the trench walls and protect adjacent structures and utilities in accordance with the excavation safety requirements of the applicable regulations.
11.2 Conduit Assembly and Spacers
11.2.1 Manufactured duct spacers (interlocking base and intermediate spacers) shall be used to hold the conduits at the specified uniform horizontal and vertical separation throughout the encasement.
11.2.2 Spacers shall be installed at intervals not exceeding the spacing selected, and not fewer than the manufacturer's minimum number of spacer locations per length of duct, with closer spacing for larger conduit, deep trenches, or unstable soil.
11.2.3 The conduit assembly shall be anchored to the trench bottom or otherwise restrained against flotation and displacement before and during the concrete pour.
11.2.4 Conduit joints shall be staggered between adjacent ducts so that joints do not align in the same cross-sectional plane.
11.3 Warning Tape
NOTE Buried warning tape gives an excavator a visible warning above the duct bank before the dig reaches it, and detectable tape allows the duct bank to be located from the surface. (11.3.1)
● Detectable (metallized) red warning tape
○ Non-detectable red warning tape
○ Not required (red concrete envelope used instead)
11.3.2 A continuous warning tape marked for buried electric line shall be installed in the backfill above the duct bank at the depth required by NEC 300.5(D) and the contract drawings, generally about 12 in. above the duct bank.
11.3.3 Where the duct bank is to be locatable from the surface, the warning tape shall be the detectable (metallized) type, or a separate tracer means shall be provided.
11.4 Backfill and Compaction
11.4.1 Backfill shall not be placed until the concrete encasement has gained sufficient strength to resist the backfill loads, and direct-buried conduit shall not be backfilled until it has been inspected.
11.4.2 Backfill shall be placed in lifts and compacted to the density required by the civil drawings, free of rock and debris that would damage the conduit or the envelope.
11.4.3 Where the duct bank route crosses paved or structural areas, the backfill and compaction shall meet the requirements of that area's pavement or foundation design.
12 Testing and Proofing
NOTE Every duct, occupied and spare, shall be proved clear and round before any cable is pulled and before the duct bank is accepted, because a duct that fails after cables are installed cannot be corrected without removing the cables. (12.1)
12.2 Mandrel and Proofing
○ Mandrel and swab through each duct
● Mandrel, swab, and pull-rope verification through each duct
12.2.1 Every duct shall be proved clear by pulling a mandrel completely through it, followed by a swab, after the concrete has cured or the direct-buried conduit has been backfilled.
12.2.2 The proofing mandrel shall be a rigid cylinder not less than 1/4 in. smaller than the nominal duct inside diameter and not less than 12 in. long, sized to confirm that the duct is round and unobstructed.
12.2.3 A duct that does not pass the mandrel shall be cleared, and where it cannot be cleared it shall be excavated and corrected.
12.2.4 A pull rope rated for the intended pulling tension shall be installed in every occupied and spare duct after proofing.
12.3 Identification
12.3.1 Each duct shall be identified at every manhole, handhole, and termination to indicate its assigned circuit or its spare status.
12.3.2 Spare ducts shall be capped and labeled as spare at each end.
13 Delivery, Storage, and Handling
13.1 Conduit, fittings, and spacers shall be delivered in the manufacturer's original packaging with listing marks intact.
13.2 PVC duct and fittings shall be stored out of direct sunlight and supported continuously to prevent bowing and deformation.
13.3 Conduit shall be stored off the ground, protected from physical damage, and kept clean and free of soil and debris inside the bore.
13.4 Damaged, deformed, or UV-degraded conduit and fittings shall not be installed.
14 Warranty
14.1 The Contractor shall warrant the duct bank installation against defects in materials and workmanship for the warranty period, beginning at substantial completion.
14.2 The warranty shall cover correction of ducts found obstructed, collapsed, or out of tolerance, of concrete encasement found cracked or deficient, and of building and structure entries found to leak.
1 year from substantial completion
2 years from substantial completion