Telecom Duct Bank Manhole Fabrication and Installation

This article is about Telecom Duct Bank Manhole Fabrication and Installation Checklist of OSP Telecom Distribution System as per International Codes and standards.

Telecom Duct Bank Manhole Fabrication and Installation

Underground Installation

Verify that the proposed MH meet the basic standard main line manholes for Saudi Aramco telecommunications facilities as per Standard Drawing No. AA-036794.
Verify that Line manholes is designed for use in main and branch conduit systems when more than six conduits will ultimately be required.
Ensure that Manhole and central office cable vault conduit entrances is made with splayed conduit configurations
Ensure that Manhole and central office cable vault conduit entrances made with conduit terminators or conduit end bells. Conduit terminators or end bells shall be cast (encased) in the manhole walls at the time the concrete is installed.
Ensure that manhole and central office cable vault conduit entrances are constructed with full 20 feet conduit sections for a minimum distance of 12 m from the manhole/CO entrance.
Ensure that manhole and central office cable vault conduit entrances are installed so that conduits are separated from each other, both horizontally and vertically, a minimum of 50 mm in the manhole or central office wall.
Ensure that manhole and central office cable vault conduit entrances installed so that the nearest side of the manhole main entrance conduits are located 150 mm from the inside surface of the adjacent manhole wall (side wall).
Ensure that the manhole roof opening and neck is constructed to accommodate the inside base measurements of the standard manhole frame and cover (1041 mm DIA as per STD DWG# AA-036794).
Ensure that the required minimum 2.00 meters headroom for telecommunication manholes is provided for new constructed MH.
Ensure at the time a manhole is constructed, non-metallic concrete inserts are placed in the walls to provide a means for attachment of the ultimate number of cable rack supports, brackets and any other surface-mounted equipment.
Verify that a1” diameter PVC sleeve is provided for grounding wire at both opposite corner of the manhole and located 100 mm below the manhole ceiling and 100 mm from adjacent wall as per AA-036794,
SECTION “A” .
Ensure that a bonding ribbon (or minimum of # 6 AWG tinned solid copper wire) is installed in each bay on each wall, where cables are to be racked.
Ensure that all manhole hardware used are of the non-corrosive type (i.e., hot dipped galvanized or better).
Verify that each manhole is fully equipped with cable racks and rack supports at the time of construction and spaced at a maximum distance of 838 mm as illustrated in the standard manhole drawing (AA-036794, Sheet 1-4). The distance from the inside surface of the manhole wall to the first cable rack shall be 760 mm or less.
Verify that cable rack supports (S-cable rack support for line manholes and L-cable rack supports for loading manholes and other special situation manholes) are placed at the time of manhole construction.
Verify that cable rack supports are secured to the manhole walls by means of ½ by 2½ inch corrosion protected (hot dipped galvanized, stainless steel, etc.) machine bolts screwed into concrete inserts that have been cast in place.
Ensure that pulling-in iron are provided and set (cast in concrete) in the manhole wall opposite all manhole conduit entrances (windows). Pulling-in irons shall be placed during the fabrication stage (before concrete is poured).
Verify that the pulling-in iron is extend far enough into the manhole to provide a minimum clear opening of 75 mm and located 150-300 mm below and above the conduits with which they are associated and in line with the centerline of the conduits.
Ensure that Pulling-in irons are not placed closer than 150 mm to any manhole entrance window and not allowed to bear against the outside face of the manhole wall (come in contact with earth), but must have adequate cover of concrete in accordance with SAES-Q-001
Ensure that a manhole step is set in the roof opening of all manholes (with standard 4 inch depth collar) to provide a support for the ladder. The MH step shall be placed during the fabrication stage (before concrete is poured).
Verify that a sump hole is provided in the floor of all new manholes. Ensure the sump is designed and sized in accordance with Standard Drawing AA-036794.
Ensure that Hot dipped galvanized (minimum) steel manhole ladders is installed in all newly constructed manholes.
Ensure that all manholes are equipped with manhole frames and covers with minimum openings of 30 in Type B, (10 in high) frames and covers, and have an identifying mark, “TELEPHONE”, stamped in the cover to indicate ownership.
Verify that each manhole frame and cover is equipped with two locking bolts located approximately 180 degrees apart on the cover’s circumference.

B. Manhole Installation

Verify that new manholes constructed in vehicular traffic areas shall have a minimum depth of cover of 355 mm. Additional cover may be required in areas where deep (more than 100 mm) road grading is anticipated in the future.
Verify that manholes installation location is to avoid being under parked vehicles to the extent possible.
Verify the specific location for each manhole indicated on the IFC work drawings.
Verify that two layers of bituminous coating is applied to all surfaces, in direct contact with soil, of reinforced concrete elements below grade after 14 days (min) curing.
Ensure that Fuel (including petroleum, hydrocarbons, petrochemical products) or any other toxic or explosive products or chemical lines are never, under any circumstances, permitted to pass through telecommunication manholes.
Ensure that electrical cables or facilities are not permitted to be inside any telecommunications manhole. Verify that manholes are located so as to avoid these facilities.
Ensure that manholes are not located in classified or hazardous areas (see SAES-B-068) or in other areas where prohibited by SAES-B-008 or SAES-B-064.
Verify that the excavations for precast manholes provide a minimum clearance of 205 mm between the exterior wall surfaces (ends and sides) of the manhole and the surfaces of the walls of the excavation.
Verify that a minimum of 100 mm of sand or other base material is placed in the bottom of the excavation and compacted and graded to level prior to placement of a precast manhole. Ensure the final manhole position meet road grade, conduit entrance, manhole collar and frame and cover grade requirements.
Verify that the equipment used to place precast manholes have sufficient weight handling capacity for the extreme weight and size manhole being placed.
Ensure that when precast manholes are being lowered into the prepared excavation, workmen is not permitted to be in the excavation or under the manhole as it is moved.
Ensure that the top surface of the frame and cover is even with the final grade.
Verify that a ground electrode (5/8 inches in diameter by 10 feet in length) which provides a ground resistance of 25 ohms or less is provided in each manhole along with the necessary bonding ribbon and/or wire (minimum of #6 AWG tinned solid copper).
Verify that all new manholes are assigned an identification number that is:
1. Stenciled in the exterior rim of the frame, using ½ inch numbers/letters.
2. Centered evenly between the inner and outer edges of the rim, in the portion of the rim nearest the nearest the curb or roadside.”
Verify that manhole is not closer than 25 m to any pipeline in the corridor (in accordance with SAES-B-064).
Verify that all precast manholes are inspected by the KAUST Inspection Department during fabrication and construction, and prior to being placed in the ground to verify compliance with KAUST standards.