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TITLE 43TRANSPORTATION
PART 1TEXAS DEPARTMENT OF TRANSPORTATION
CHAPTER 21RIGHT OF WAY
SUBCHAPTER CUTILITY ACCOMMODATION
RULE §21.40Underground Utilities

    (A) Depth of cover for crossings. Depth of cover is the depth to the top of the encasement, or the carrier pipe if encasement is not used. Where materials and other conditions justify, such as on existing pipelines remaining in place, the district may require a minimum depth of cover under the pavement structure of 12 inches or one-half the diameter of the pipe, whichever is greater.

      (i) For encased low-pressure gas pipelines, the minimum depth of cover is:

        (I) 60 inches or one-half the diameter of the pipe, whichever is greater, below the lowest point of the crossed grade; or

        (II) 48 inches if the pipeline is outside of the pavement structure or 60 inches under ditches (original unsilted flowline).

      (ii) For unencased low-pressure gas pipelines, the minimum depth of cover is:

        (I) 60 inches under the lowest point of the crossed grade;

        (II) 48 inches if the pipeline is outside of paved areas; or

        (III) a lesser depth than applicable under subclause (I) or (II) of this clause if the lesser depth is authorized by the district where a reinforced concrete slab is used to protect the pipeline.

    (B) Depth of cover for longitudinal placement. The minimum depth of cover for longitudinal installations is 48 inches.

    (C) Encasement. Low-pressure gas pipelines crossing the pavement shall be placed in a high-density polyethylene (HDPE) or equivalent encasement. The district may waive this encasement requirement if:

      (i) the pipeline is:

        (I) of welded steel construction; and

        (II) is protected from corrosion by cathodic protective measures or cold tar epoxy wrapping; and

      (ii) the utility signs a written agreement that the pavement will not be cut for pipeline repairs at any time in the future.

    (D) Vents. One or more vents shall be provided for each encasement or series of encasements. For encasements longer than 150 feet, vents shall be provided at both ends. On shorter encasements, a vent shall be located at the high end with a marker placed at the low end. Vents shall be placed at the right of way line immediately above the pipeline, situated so as not to interfere with highway maintenance or be concealed by vegetation, and may not be greater than six inches in diameter. The utility's name, address, and emergency telephone number shall be shown on each vent.

    (E) Aboveground appurtenances. Except for vents, pipeline markers, and gas rectifiers, aboveground utility appurtenances for gas lines are prohibited within department's right of way.

  (2) High-pressure pipelines and saltwater pipelines.

    (A) Depth of cover for crossings.

      (i) Depth of cover is the depth to the top of the encasement or carrier pipe if an encasement is not used. Where materials and other conditions justify, such as on existing lines remaining in place, the district may approve a minimum depth of cover under the pavement structure of 48 inches or one-half the diameter of the pipe, whichever is greater. For encased high-pressure pipeline, the minimum depth of cover is:

        (I) 60 inches or one-half the diameter of the pipe, whichever is greater, below the lowest point of the crossed grade unless a greater depth is required by the district; or

        (II) 48 inches if the pipeline is outside of the pavement structure, or 60 inches if under a ditch, below the lowest point of grade.

      (ii) Where a reinforced concrete slab is used to protect the pipeline, the district may authorize a reduction in the depths specified in this subparagraph.

      (iii) For unencased high-pressure pipelines, the minimum depth of cover is as follows:

        (I) 60 inches under the lowest point of the crossed grade, subject to subparagraph (D) of this paragraph; or

        (II) 60 inches under the lowest point of grade if the pipeline is placed outside the pavement structure or under a ditch.

    (B) Depth of cover for longitudinal placement. The minimum depth of cover is 48 inches.

    (C) Encasement. The encasement must be a vented steel pipe.

    (D) Unencasement.

      (i) Where encasement is not employed, the utility shall show that the welded steel carrier pipe will provide sufficient strength to withstand the internal design pressure and the dead and live loads of the pavement structure and traffic. Additional protective measures must include:

        (I) heavier wall thickness, higher factor of safety in design, or both;

        (II) adequate coating and wrapping;

        (III) cathodic protection; and

        (IV) the use of Barlow's formula regarding maximum allowable operating pressure and wall thickness, as specified in 49 CFR §192.105.

      (ii) Shallow anode bed types exceeding 48 inches in width may not be used in the department's right of way. All others must have a depth of coverage of at least 36 inches. Deep well anode beds of up to 60 inches in diameter are acceptable. Rectifier and meter loop poles shall be placed at or near the right of way line.

      (iii) The minimum length of the additional protection is the same as that required for an encased crossing.

      (iv) The district may allow existing lines under low-volume highways to remain in place without encasement or extension of encasement if they are protected by a reinforced concrete slab or equivalent protection or if they are located at a depth of five feet under the pavement structure and not less than four feet under a highway ditch.

    (E) Vents. Vents shall be installed at both ends of an encasement, regardless of length, with a marker on at least one end. Vents shall be placed at the right of way line immediately above the pipeline, situated so as not to interfere with highway maintenance or be concealed by vegetation. The utility's name, address, and emergency telephone number shall be shown on each vent marker.

    (F) Aboveground appurtenances. Except for vents, pipeline markers, and gas rectifiers, above ground appurtenances are prohibited within department's right of way.

(c) Water lines.

  (1) Material type. All material types used for water lines shall conform to American Water Works Association, applicable local requirements, and 30 TAC §290.44(a) (relating to Water Distribution).

  (2) Depth of cover. The minimum depth of cover is 36 inches from the lowest point of grade for longitudinal utility facilities, and 60 inches from the lowest point of grade for all crossings.

  (3) Encasement. Water lines crossing under paved highways shall be placed in an encasement pipe within the department's right of way. Existing water lines that are 24 inches or greater in diameter may be allowed to remain unencased under the pavement of new low volume highways, provided that the depth and all other requirements of 30 TAC §290.44 are met.

  (4) Manholes. The width dimensions of manholes may not be larger than is necessary to hold equipment involved and to meet safety standards for maintenance personnel. The maximum inside diameter of the manhole chimney may not exceed 48 inches. The outside diameter of the manhole chimney at the ground level may not exceed 36 inches.

  (5) Aboveground appurtenances.

    (A) Fire hydrants and valves. When feasible, fire hydrants and blow-off valves shall be located at the right of way line. Fire hydrants may not be placed in the sidewalk or any closer than five feet from the back of the curb. Valve locations shall be placed so as not to interfere with maintenance of the highway.

    (B) Water meters. Individual service meters shall be placed outside of the department's right of way. Master meters for a point of service connection may be placed in a manhole with a maximum width of 48 inch inside diameter. If additional volume is required, a manhole with a neck of 60-inch depth shall be used.

(d) Non-potable water control facilities.

  (1) Applicability. This subsection applies to agricultural irrigation facilities, water control improvement districts, municipal utility districts, flood control districts, canals, and similar non-potable water control facilities.

  (2) Depth of cover. The minimum depth of cover, regardless of type of pipe used, is 36 inches for longitudinal utility facilities, and 60 inches from the lowest point of grade for all crossings.

  (3) Encasement. All non-potable water control lines crossing under paved highways shall be encased. At the district's discretion, encasement may be omitted under center medians and outer separations that are more than 76 feet wide.

  (4) Location and design requirements. Longitudinal buried pipe facilities installed within the right of way must conform with §21.41(c) of this subchapter (relating to Overhead Electric and Communication Lines), consistent with the clearances applicable to all roadside obstacles. Open ditch facilities may not be installed longitudinally within the department's right of way. Aboveground appurtenances within the horizontal clearance of the highway facility are prohibited.

  (5) Levee/ditch travel road location. Coordination with and approval by the district is required where levee/ditch travel roads intersect the highway.

(e) Sanitary sewer lines.

  (1) Material type. All material types used for sanitary sewer lines must conform to applicable provisions of 30 TAC Chapter 217 and applicable local requirements.

  (2) Depth of cover. The minimum depth of cover for gravity lines is 30 inches and not less than 18 inches below any pavement structure. The minimum depth of cover for pressurized sanitary sewer lines is 60 inches for crossings and 36 inches for longitudinal utility facilities.

  (3) Encasement. All crossings of paved highways within the right of way shall be encased. At the district's discretion, the district may exempt the encasement requirement under center medians and outer separations that are more than 76 feet wide.

  (4) Manholes. Manholes serving sewer lines up to 12 inches shall have a maximum inside diameter of 48 inches. For lines larger than 12 inches, the manhole inside diameter may be increased an equal amount, up to a maximum diameter of 60 inches. Manholes for large interceptor sewers shall be designed to keep the overall dimensions to a minimum. The outside diameter of the manhole chimney at the ground level may not exceed 36 inches.

  (5) Lift stations. Lift stations and pump stations for sanitary sewer lines shall be located outside of the department's right of way.

(f) Electric lines Lines.

  (1) Depth of cover for longitudinal placement. All underground electric lines placed longitudinally within the right of way may be installed by direct bury at depths equal to or greater than 48 inches.

  (2) Depth of cover for crossings. The minimum depth of cover for underground electric lines is 60 inches below the lowest point of the crossed grade.

  (3) Encasement. Electric lines crossing the roadway shall be encased in high-density polyethylene(HDPE) or comparable material with a strength greater than or equal to ductile iron, with satisfactory joints, or materials and designs that provide equal or better protection of the integrity of the highway system and resistance to damage from corrosive elements to which they may be exposed. The lines shall be buried a minimum of 60. Encasement shall be provided as outlined in this section.

  (4) Installation. The utility facility shall be located as set forth in §21.37(b) of this subchapter (relating to Design).

  (5) Aboveground appurtenances.

    (A) Aboveground appurtenances installed as part of an underground electric line shall be located at or near the right of way line, and may not impede highway maintenance or operations.

    (B) Structures that are larger in plan view than single poles may be placed on the right of way if:

      (i) the installation does not hinder highway maintenance operations;

      (ii) the housing is placed at or near the right of way line;

      (iii) the installation does not reduce visibility and sight distance of the traveling public;

      (iv) the dimensions of the housing are minimized, particularly where the need to allow space for highway improvement or accommodation of other utility lines is apparent;

      (v) the outside width, length (longitudinal with respect to the right of way), and height dimensions of the aboveground portion of the housing do not exceed 36 inches, 60 inches, and 54 inches, respectively;

      (vi) the supporting slab does not project more than three inches above the ground line, nor extend more than 12 inches on either side of the housing structure; and

      (vii) the installation is compatible with adjacent land uses.

  (6) Manholes. Manholes serving electric lines shall conform to the requirements of this section.

(g) Underground communication lines.

  (1) Joint duct banks. Where a department joint duct bank is available, a utility shall install a utility facility in the duct bank unless otherwise authorized by the district.

Cont'd...

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