6-Attachment 4-1 - Pathways for AV System Specifications.pdf

Project #2024-03580-00 PATHWAYS FOR AV SYSTEMS

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SECTION 270529

PATHWAYS FOR AV SYSTEMS

PART 1 - GENERAL

1.1 SECTION INCLUDES

A. Conduits

B. Pull Boxes

C. Conduit Fittings

D. Floor Boxes

E. Cable Tray

1.2 DESCRIPTION OF WORK

A. Furnish and install all items listed in 1.1 required to support the AV systems cabling as indicated on the AV drawings, specified, or as otherwise required.

PART 2 - PRODUCTS

2.1 GENERAL

A. Refer to AV Drawings for pathway type required for each cable run. Substitution of pathway type requires Consultant’s approval. Pathways shown without cable fill are for temporary or future cable use.

2.2 CONDUITS

A. General

1. Provide Pull String in all conduits for AV system.

2. The sizes of conduits shall be as shown on the drawings, minimum size is 0.75".

All conduits shall be reamed and furnished with insulation and/or grounded bushings as required.

B. Flexible Steel Conduit

1. Flexible steel conduits are not acceptable for AV systems installations

C. Electrical Metallic Tubing (EMT)

1. EMT shall be zinc galvanized both inside and out with a minimum thickness of

.0008”. It shall be round with uniform wall thickness and continuously welded seams. EMT shall be furnished in ten-foot standard lengths.

D. PVC Conduit

1. PVC conduit shall be rigid non-metallic Schedule 40 heavy wall.

2. Use of PVC shall be limited to underground conduits only.

E. Conduits carrying fiber cables shall have large labels indicating “Fiber Optic Cable.”

These labels should be placed every 10 feet where exposed.

F. Buried conduits must have yellow “Caution Fiber Optic” tape laid 12 inches above duct bank.

2.3 PULL BOXES

A. Pull boxes shall be constructed of code gauge steel, etched, primed and shall have rust resistant ANSI 61 gray finish and be NEMA 1 construction with screw covers unless noted otherwise. For conduits 1-1/4" and larger terminating in a pull box, the minimum length of pull box shall be 8 times the diameter of the largest conduit terminating in the pull box. Splice boxes shall be sized as per EIA/TIA-569A Table 5.2- 3.

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B. Location and sizes of pull boxes and splice boxes shall meet the approval of the Architect and Consultant. Condulete type fittings (e.g. LB's, etc.) shall not be used in lieu of pull boxes or bends.

C. Exposed pull boxes in public areas shall be provided with tamperproof screws.

D. Boxes shall be free from unused openings, including knockouts.

E. Pull boxes larger than 12” x 12” for which a custom panel has not been specified, shall have hinged covers.

F. Gang, 4” square and 4-11/16” square boxes must be installed using open center brackets

G. Pull boxes for indoor wet or damp locations shall be NEMA 3R Rated with stainless steel screws.

H. Pull boxes for outdoor locations shall be NEMA 4X Rated stainless steel continuous hinges, door clamps and a hasp.

I. Provide junction box, pull box, and hand-hole assemblies sized as required by the NEC. Pull boxes/hand-holes shall be located using the following table:

1. Runs with total of all bends <90 degrees – 600ft.

2. Runs with total of all bends >=90 degrees and <180 degrees – 400ft.

3. Runs with total of all bends >= 180 degrees and <270 degrees – 200ft.

4. Runs with total of all bends >= 270 degrees are not allowed.

2.4 CONDUIT FITTINGS

A. All rigid, IMC and EMT fittings shall be galvanized malleable iron or steel. Connectors and couplings shall be threaded, setscrew, compression type, and concrete-tight.

B. Conduit bodies shall be malleable iron, threaded type. Provide neoprene cover gaskets for conduit body covers exposed to the weather.

C. Expansion fittings shall be O-Z/Gedney Type "AX" for rigid metal conduit and Type "TX" for electrical metallic tubing. For intermediate metal conduit applications, a 15-inch minimum length of rigid metal conduit shall be used with a Type "AX" expansion fitting. Provide O-Z/Gedney Type "BJ" bonding jumpers at all expansion fittings.

D. Rigid and IMC conduit bushings shall be of the insulated type with phenolic thermosetting insulation molded to a hot dipped galvanized malleable iron body of the threaded type.

E. EMT fittings shall be of the insulated throat type. Fittings larger than 2-1/2 inches shall have threaded bushings installed.

F. PVC conduit fittings shall be slip joint type.

G. All conduit sleeves will be fitted with “spillways” to maintain the bend radius of cables passing through the sleeve.

2.5 FLOOR BOXES

A. Refer to AV drawings for manufacturer, model, quantity, and location information.

B. Contractor to provide all parts and accessories required for a working floor box system including those required based on specific installation conditions unless otherwise noted.

C. Boxes to have a voltage divider to allow for power receptacles and low-voltage AV connections to reside within the same box. Conduits for high and low voltages must enter box on appropriate side of voltage divider to maintain separation. High and low-voltage wires may not cross within the box.

D. On-grade boxes to be cast-iron, and above grade, in-slab boxes to be steel.

E. Boxes to be fully adjustable, before and after the concrete pour.

F. Boxes shall have applicable approvals from a Nationally Recognized Testing Laboratory and meet all applicable local codes.

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G. Floor Boxes on elevated floors must maintain proper fire rating of slab.

H. Provide equipment ground conductor as required by local code.

2.6 CABLE TRAY

A. Cable trays shall be installed as indicated on the AV drawings.

B. Unless otherwise noted on the Drawings, cable tray shall be 12 inches wide and have a usable minimum loading depth of 4 inches deep.

C. Industrial type, single-piece, formed aluminum trough cable tray for heavy cable loads and large cables shall be Chalfant Ladder Tray or Type 156 by B-Line, 4” usable depth and 9” rungs as indicated on the drawings. The tray shall be either trapeze or wall mounted.

D. Industrial type, single-piece, 16-ga fully welded tubular steel with 2-layer black powder coat finish with 9” rungs as indicated on the drawings.

E. Cable tray used in open ceilings in finished areas and storage rooms shall be solid bottom.

F. Straight sections shall be a maximum nominal 10-foot length.

G. Straight sections and fittings shall be assembled with nut and bolted splice plates.

Hardware shall be zinc plated. Spring loaded and "snap" type fittings are not acceptable.

H. Factory end plates and fittings shall match the tray width, depth and metal type.

I. The cable tray system shall be U.L. Listed and classified with applicable U.L. labels applied. Cable tray installation shall meet all applicable UL standard requirements for use as an equipment ground conductor.

PART 3 - EXECUTION

3.1 INSTALLATION

A. General

1. Whenever possible, cable and raceway routing paths shall follow the logical structure of the building (e.g. follow hallways, aisles and corridors). Route all AV cables and raceways parallel to or perpendicular to the building structure. No diagonal runs will be permitted unless noted otherwise or pre-approved by the Architect and Consultant. Corridor crossovers shall be kept to a minimum.

2. Coordinate layout of conduits including specific routing and mounting elevations with building structure and work of other trades.

3. Provide a pull string in all raceways, cable trays and conduits.

4. Transitions between cable trays and conduit, etc. shall not exceed 10” horizontally, 24” vertically. Provide “drop-out” supports spillways, and radius controls for changes in elevation as required.

5. All power devices and power sources emit a given amount of radio frequency interference (RFI) and/or electro-magnetic interference (EMI). To reduce or eliminate the field effects of RFI/EMI on the signals residing on a given cable, runs shall be kept at the maximum possible distance from such sources. Running cables through the center of the building can reduce the external interference effects of RFI/EMI in the cable tray. Open wiring and non-metallic raceway shall be routed a minimum of twelve (12") inches away from fluorescent fixtures. Special attention shall be given to the routing of such pathways away from lighting ballasts and high intensity discharge devices. Reference AV0.00 for the required separation distances of signals of different types.

B. Conduits

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1. Provide continuous conduits across open or inaccessible ceiling areas. Exposed conduits shall be installed parallel and perpendicular to nearby surfaces and structural members. Exposed conduits shall be painted to match the surrounding surfaces. Coordinate color with Architect.

2. Changes from home run conduits to stub up must be approved by The Consultant.

3. Provide conduits from cable trays to accessible ceilings as required.

4. Conduits attached to cable trays shall be secured with approved conduit clamps.

5. Conduit buried in concrete slab pours shall be full weight rigid galvanized steel or

Schedule 40 PVC. All elbows, stub ups and conduit above ground shall be rigid galvanized steel. All joints and terminations for PVC shall be made according to manufacturer's recommendations to ensure all joints are watertight.

6. Conduit buried in or beneath building slabs or exterior below grade shall be full weight rigid galvanized steel or Schedule 40 PVC. The conduit shall be encased in 3" concrete envelope or as called for on the Plan Drawings. All elbows and stub ups shall be rigid galvanized steel. All joints and terminations for PVC shall be made according to manufacturer's recommendations to ensure all joints are watertight.

7. Conduits and cables entering from outside the building shall be sealed water and moisture tight. Seal between conduit and sleeves, conduits and core drilled holes and around conductors inside conduits. Provide cast iron pipe or Schedule 40 galvanized steel conduit sleeves in exterior walls below grade, with intermediate wall stop and anchor collar set in place before concrete pouring. Sleeve shall be a part of the sealing assembly. When the wall opening is core drilled, the wall sleeve may be omitted. A mechanically compressed rubber sealing assembly shall be placed in the annular space between conduit and the sleeve or the core drilling.

8. Conduits stubbed out into accessible ceiling to be located no more than 2’-6” above finished ceiling.

9. All conduit stub-outs and junction boxes in accessible ceilings to remain accessible by ladders from the finished floor below.

10. Layout the conduit system to avoid crossing building expansion joints. Where crossings are necessary, use expansion joints.

C. Boxes

1. Wall or ceiling boxes must be mounted flush with finished surface.

2. Final mounting height of all boxes on finished surfaces to be coordinated with

Architect for alignment with adjacent boxes.

3. In stud walls, boxes on opposite sides of the wall must be separated by a minimum of 1 stud cavity.

4. In CMU or concrete walls, boxes on opposite sides of the wall must be separated by a minimum of 16”.

5. Pull boxes shall be placed in straight sections of conduit runs and may not be used in lieu of a bend without approval of the Consultant. Pull boxes and/or splice boxes shall be installed in readily accessible locations. Where boxes are installed above suspended ceilings, they shall be located immediately above the suspended ceiling or the ceiling shall have a suitably marked and hinged panel to facilitate direct access to the pull box.

6. Boxes in accessible ceiling to be located no more than 2’-6” above finished ceiling.

7. All boxes mounted in accessible drop tile ceilings to remain accessible by ladders from the finished floor below.

D. Cable Tray

1. Cable trays shall be trapeze hung and sway braced.

2. Cable trays will not be permitted in mechanical rooms, electrical rooms or any wet or damp rooms. In these area conduits are required.

3. All changes in elevation of the cable tray or where cable leaves the cable tray factory produced radius drop offs, waterfalls and other devices shall be used to ensure the proper cable bend radius is maintained.

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4. When rated walls must be breached, cables shall pass through pre-established fire block systems by EZ-Path or similar. Multiple systems shall be used to equal the full capacity of the cable tray. Cables shall enter and/or exit areas at right angles to the structure.

E. Fire Stopping

1. Where pathways pierce walls, floors and/or ceilings, restore fire rating and smoke stoppage integrity as required by code.

F. Excavation:

1. It is the responsibility of the Contractor to obtain all permits and utility marking.

Bids shall include landscaping restoration costs.

END OF SECTION