1. (a) General.

   1. (1) Encasement.

      1. (A) Underground utilities crossing the highway shall be encased in the interest of safety, protection of the utility, protection of the highway, and for access to the utility. Casing shall consist of a pipe or other separate structure around and outside the carrier line. The utility must demonstrate that the casing will be adequate for the expected loads and stresses.
      2. (B) Casing pipe shall be steel, concrete, or plastic pipe as approved by the district, except that if horizontal directional drilling is used to place the casing, high-density polyethylene (HDPE) pipe must be used in place of plastic pipe.
      3. (C) Encasement may be of metallic or non-metallic material. Encasement material shall be designed to support the load of the highway and superimposed loads thereon, including that of construction machinery. The strength of the encasement material shall equal or exceed structural requirements for drainage culverts and it shall be composed of material of satisfactory durability for conditions to which it may be subjected. The length of any encasement under the roadway shall be provided from top of backslope to top of backslope for cut sections, five feet beyond the toe of slope for fill sections, and five feet beyond the face of the curb for curb sections. These lengths of encasement include areas under center medians and outer separations, unless otherwise specifically addressed in subsections (b) - (f) of this section.
      4. (D) The department will provide an example graphic upon request of a typical section showing encasement lengths.

   2. (2) Depth. Where placements at the depths in this section are impractical or where unusual conditions exist, the department may allow installations at a lesser depth, but will require other means of protection, including encasement or the placement of a reinforced concrete slab. Reinforced concrete slabs or caps shall meet the following standards:

      1. (A) width--five feet, or three times the diameter of the pipe, whichever is greater;
      2. (B) thickness--six inches, at minimum;
      3. (C) reinforcement--#4 bars at 12 inch centers each way or equivalent reinforcement; and
      4. (D) cover--no less than six inches of sand or equivalent cushion between the bottom of the slab/cap and the top of the pipe.

   3. (3) Manholes.

      1. (A) Manholes shall not be installed unless necessary for installation and maintenance of underground lines. In no case shall a manhole be placed or permitted to remain in the pavement or shoulder of a highway. However, on noncontrolled access highways in urban areas, the district may, in its discretion, allow existing lines to remain in place under existing or proposed highways. In these cases, manholes may remain in place or be installed under traffic lanes of low volume highways in municipalities only if measures are taken to minimize the installations and to avoid locating them at intersections or in wheel paths.
      2. (B) To conserve space, a manhole's dimensions shall be the minimum acceptable by appropriate engineering and safety standards. The only equipment that may be installed in manholes located on the right of way is that essential to the normal flow of the utility, such as circuit reclosers, cable splices, relays, valves, and regulators. Other equipment, such as substation equipment, large transformers, and pumps, shall be located outside the right of way.
      3. (C) Inline manholes are the only type permitted within the right of way. The width dimensions shall be no larger than necessary to hold equipment involved and to meet safety standards for maintenance personnel. Outside width, the dimension of the manhole perpendicular to the highway, shall not exceed ten feet, with the length to be held to a reasonable minimum. The outside diameter of the manhole chimney at the ground level shall not exceed 36 inches, except that if the utility demonstrates necessity, the district may, at its discretion, allow an outside diameter of up to 50 inches. The top of the roof of the manhole shall be five feet or more below ground level.
      4. (D) All manhole covers shall be installed flush with the ground or pavement structure. In order to minimize vandalism, manhole covers must weigh at least 175 pounds. Manhole rings and covers must be designed for HS-20 loading.
      5. (E) Manholes shall be straight, inline installations with a minimum overall width necessary to operate and maintain the enclosed equipment. The utility is responsible for any adjustment of the manhole rim that may be needed to meet grade changes.

   4. (4) Installation.

      1. (A) Lines placed beneath any existing highway shall be installed by boring or tunneling. Jacking may not be used unless approved in writing by the district. The district may require encasement of lines installed by boring or jacking. The use of explosives is prohibited. Pipe bursting or fluid/mist jetting may be allowed at the discretion of the department.

      2. (B) For rural, uncurbed highway crossings, all borings shall extend beneath all travel lanes. Unless precluded by right of way limitations, the following clearances are required for rural highway crossings:

         1. (i) 30 feet from all freeway mainlanes and other high-speed (exceeding 40 mph) highways except as indicated in clauses (ii) - (iv) of this subparagraph;
         2. (ii) 16 feet for high-speed highways with current average daily traffic volumes of 750 vehicles per day or fewer;
         3. (iii) 16 feet for ramps; or
         4. (iv) ten feet for low-speed (40 mph or less) highways.
      3. (C) Annular voids greater than one inch between the bore hole and carrier line (or casing, if used) shall be filled with a slurry grout or other flowable fill acceptable to the department to prevent settlement of any part of the highway facility over the line or casing.

      4. (D) For curbed highway crossings, all borings shall extend beneath travel and parking lanes and extend beyond the back of curb, plus:

         1. (i) 30 feet from facilities with speed limits of 40 mph or greater; or
         2. (ii) five feet from facilities with speed limits of less than 40 mph or less, plus any additional width necessary to clear an existing sidewalk.
      5. (E) Where circumstances necessitate the excavation of a bore pit or the presence of directional boring equipment closer to the edge of pavement than set forth in paragraphs (2) or (3) of this subsection, approved protective devices shall be installed for protection of the traveling public in accordance with §21.38 of this subchapter. Bore pits shall be located and constructed in such a manner as not to interfere with the highway structure or traffic operations. If necessary, shoring shall be utilized for the protection of the highway, and must be approved by the district.
      6. (F) All traffic control devices, including signs, markings, or barricades used to warn motorists and pedestrians of the construction activity must conform to the TMUTCD.
      7. (G) When trenching longitudinally, backfill or stabilized sand shall be compacted to densities equal to that of the surrounding soil.
   5. (5) Nonmetallic pipe detection. Where nonmetallic pipe is installed, whether longitudinally or at a crossing, a durable metal wire or other district-approved means of detection shall be concurrently installed.

   6. (6) Unsuitable conditions. The following conditions are generally unsuitable or undesirable for pipeline crossings and shall be avoided:

      1. (A) deep cuts;
      2. (B) locations near footings or bridges and retaining walls;
      3. (C) crossing intersections at-grade or ramp terminals;
      4. (D) locations at cross-drains where the flow of water may be obstructed;
      5. (E) locations within basins or underpasses drained by pump if the pipeline carries a liquid or liquefied gas; or
      6. (F) terrain where minimum depth of cover would be difficult to attain.
   7. (7) Clearances. Except as specified in this subchapter, there shall be a minimum of 12 inches vertical and horizontal clearance between a pipeline and an existing utility, unless a greater clearance is required by the district. However, if an installation of another utility or highway feature cannot take place without disturbing an existing utility, the minimum clearance will be 24 inches.
   8. (8) Crossings. A district may require crossings with no longitudinal connections to be encased within the right of way.
   9. (9) Drainage easements. Where it is necessary for pipelines to cross department drainage easements outside of the right of way, the depth of cover shall be as specified for each type of utility. In cases where soil conditions are such that erosion might occur, or where it is not feasible to obtain specified depth, it shall be the responsibility of the utility to install retards, energy dissipators, encasement, or concrete or equivalent slabs/caps over the pipe, as approved by the department. Where grades on the pipelines must be maintained, such as gravity flow sewer lines, each case will be reviewed on an individual basis, keeping in mind that the main purpose of the channel is to carry drainage water and that this flow must not be obstructed. The utility owner is responsible for obtaining any other approvals to occupy the drainage easement.

   10. (10) Existing installations in a highway or transportation project. At the district's discretion, existing longitudinal lines in a highway or transportation project that otherwise meet the requirements of this subchapter may remain in place if the lines:

       1. (A) can be maintained in accordance with §21.37(b)(2) of this subchapter; and
       2. (B) are not located under the pavement structure or shoulder of any proposed or existing highway.
   11. (11) Markers. If a high pressure gas or liquid petroleum line crosses a highway, the utility shall place a readily identifiable, durable, and weatherproof marker over the centerline of the pipe at each right of way line. Readily identifiable, durable, and weatherproof markers shall be placed at a minimum distance of 500 feet or line of sight at the right of way line for pipelines installed longitudinally within the right of way. All markers shall indicate the name, address, emergency telephone number of the owner/operator, and offset from the right of way line. For gas or petroleum pipelines, the pipeline product, operating pressure, and depth of pipe below grade shall also be indicated on the markers. At locations where underground utilities have been allowed to cross at an angle other than 90 degrees to centerline, the district may require additional markers in the medians and outer separations of the highway.
   12. (12) Backfilling. Underground utility installations shall be backfilled with pervious material and outlets for underdrainage.
   13. (13) Underdrainage. Underdrains shall be provided where necessary. No puddling beneath the highway will be permitted.

2. (b) Gas and liquid petroleum lines.

   1. (1) Low-pressure lines.

      1. (A) Depth of cover for crossings. Depth of cover is the depth to the top of the carrier pipe or casing, as applicable. Where materials and other conditions justify, such as on existing lines 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.

         1. (i) For encased low-pressure gas lines, the minimum depth of cover shall be:

            1. (I) 18 inches or one-half the diameter of the pipe, whichever is greater, under pavement structure;
            2. (II) 24 inches outside pavement structure and under ditches (original unsilted flowline); or
            3. (III) 30 inches for unencased sections of encased lines outside of pavement structure.

         2. (ii) For unencased low-pressure gas lines, the minimum depth of cover shall be:

            1. (I) 60 inches under the pavement surface or 18 inches under the pavement structure for paved areas;
            2. (II) 48 inches outside paved areas and under ditches (original unsilted flowline); or
            3. (III) a lesser depth if authorized by the district where a reinforced concrete slab is used to protect the pipeline.
      2. (B) Depth of cover for longitudinal placement. The minimum depth of cover for longitudinal installations shall be 36 inches.
      3. (C) Encasement. Low-pressure gas lines crossing the pavement shall be placed in a steel encasement. The district may waive this encasement requirement if the line is of welded steel construction and is protected from corrosion by cathodic protective measures or cold tar epoxy wrapping, and the utility signs a written agreement that the pavement will not be cut for pipeline repairs at any time in the future.
      4. (D) Vents. One or more vents shall be provided for each casing or series of casings. For casings longer than 150 feet, vents shall be provided at both ends. On shorter casings, 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 shall be no greater than six inches in diameter. The owner's name, address, and emergency telephone number shall be shown on each vent.
      5. (E) Plastic lines. Plastic lines shall be encased within the right of way on crossings, and must have at least 30 inches of cover.
      6. (F) Aboveground appurtenances. Except for vents, no above ground utility appurtenances for gas lines shall be permitted within the right of way.

   2. (2) High-pressure lines.

      1. (A) Depth of cover for crossings.

         1. (i) Depth of cover is the depth to the top of the carrier pipe or casing, as applicable. 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 12 inches or one-half the diameter of the pipe, whichever is greater. For encased high-pressure gas or liquid petroleum lines, the minimum depth of cover shall be:

            1. (I) the greater of 18 inches or one-half the diameter of the pipe, under pavement structures;
            2. (II) 30 inches if the line is outside the pavement structure or under a ditch; or
            3. (III) 36 inches for unencased sections of encased lines outside the pavement structure.

         2. (ii) Where a reinforced concrete slab is used to protect the pipeline, the district may authorize a reduction in the depths specified in this section. For unencased high-pressure gas or liquid petroleum lines, the minimum depth of cover is as follows:

            1. (I) 60 inches under the pavement surface or 18 inches under the pavement structure in paved areas; or
            2. (II) 48 inches if the line is placed outside the pavement structure or under a ditch.
      2. (B) Depth of cover for longitudinal placement. The minimum depth of cover shall be 48 inches.
      3. (C) Encasement. Casing shall consist of a vented steel pipe.

      4. (D) Unencasement.

         1. (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:

            1. (I) heavier wall thickness, higher factor of safety in design, or both;
            2. (II) adequate coating and wrapping;
            3. (III) cathodic protection; and
            4. (IV) the use of Barlow's formula regarding maximum allowable operating pressure and wall thickness, as specified in 49 CFR §192.105.
         2. (ii) Shallow anode bed types exceeding 48 inches in width shall not be permitted in the 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.
         3. (iii) The minimum length of the additional protection shall be the same as that required for an encased crossing.
         4. (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.
      5. (E) Vents. Vents shall be installed at both ends of a casing, 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 owner's name, address, and emergency telephone number shall be shown on each vent marker.
      6. (F) Aboveground appurtenances. Aboveground appurtenances, except vents for gas lines, shall not be permitted within the right of way.

3. (c) Water lines.

   1. (1) Material type. All material types used for water lines shall conform to American Waterworks Association, applicable local requirements, and 30 TAC §290.44(a).
   2. (2) Depth of cover. The minimum depth of cover shall be 30 inches, but not less than 18 inches below the pavement structure for crossings.
   3. (3) Encasement. Unless another type of encasement is approved by the district, water lines crossing under paved highways must be placed in a steel encasement pipe within the limits of the right of way. At the district's discretion, encasement may be omitted under center medians and outer separations that are more than 76 feet wide. At the district's discretion, encasement under side road entrances may be omitted in consideration of traffic volume, condition of highway, maintenance responsibility, or district practice. Existing water lines 24 inches or greater may be allowed to remain unencased under the pavement of new low volume highways, provided depth and all other requirements of 30 TAC §290.44 are met.
   4. (4) Manholes. The width dimensions shall be no larger than is necessary to hold equipment involved and to meet safety standards for maintenance personnel. The maximum inside diameter of the manhole chimney shall not exceed 48 inches. The outside diameter of the manhole chimney at the ground level shall not exceed 36 inches.

   5. (5) Aboveground appurtenances.

      1. (A) Fire hydrants and valves. When feasible, fire hydrants and blow-off valves are to be located at the right of way line. Fire hydrants shall 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.
      2. (B) Water meters. Individual service meters shall be placed outside the limits of the 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 must be used.
      3. (C) Service lines crossing highway by bore. Lines for customer service that cross the highway may be placed in a high-density polyethylene (HDPE) encasement pipe without joints (rolled pipe).

4. (d) Nonpotable water control facilities.

   1. (1) Applicability. This subsection applies to agricultural irrigation facilities, water control improvement districts, municipal utility districts, flood control districts, canals, and similar nonpotable water control facilities.
   2. (2) Depth of cover for buried pipe facilities. The minimum depth of cover, regardless of type of pipe used, shall be 30 inches, but not less than 18 inches below any pavement structure.
   3. (3) Encasement for buried pipe facilities. Unless the district approves another type of encasement, all non-potable water control lines crossing under paved highways within the right of way must be placed in a steel encasement pipe. At the district's discretion, encasement may be omitted under center medians and outer separations that are more than 76 feet wide.
   4. (4) Location and design requirements. Open ditch facilities and buried pipe facilities designed and constructed in accordance with this subchapter may be installed across the right of way. Longitudinal buried pipe facilities installed within the right of way must conform with §21.41(c) of this subchapter, consistent with the clearances applicable to all roadside obstacles. Open ditch facilities shall not be installed longitudinally within the right of way, nor will any aboveground appurtenances be permitted within the horizontal clearance.
   5. (5) Levee/ditch travel road location. Coordination with and approval by the district is required where levee/ditch travel roads intersect the highway.

5. (e) Sanitary sewer lines.

   1. (1) Material type. All material types used for sanitary sewer lines shall conform to 30 TAC §317.2 and applicable local requirements.
   2. (2) Depth of cover. The minimum depth of cover shall be 30 inches, but not less than 18 inches below any pavement structure.
   3. (3) Encasement. Pressurized line crossings under paved highways within the limits of the right of way shall be placed in a steel encasement pipe. Gravity flow lines not conforming to the minimum depth of cover shall be encased in steel or concrete. At the district's discretion, encasement may be omitted under center medians and outer separations that are more than 76 feet wide.
   4. (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 shall not exceed 36 inches.
   5. (5) Lift stations. Lift stations and pump stations for sanitary sewer lines exceeding 48 inches inside diameter shall be located outside the limits of right of way.

6. (f) Electric and communication Lines.

   1. (1) Underground electric lines.

      1. (A) Depth of cover. All underground electric lines placed within the right of way may be installed by direct bury at depths according to the voltage of electric lines as required by the National Electrical Safety Code and as shown in the following chart.
         Attached Graphic
         
      2. (B) Encasement. Electric lines crossing the roadway shall be encased in steel or comparable material greater than or equal to that of ductile iron, with satisfactory joints, or materials and designs that will 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 36 inches under highway ditches, and 60 inches below the pavement structure. Encasement shall be provided as outlined in this section.
      3. (C) Installation. Longitudinal underground electric lines may be placed by plowing or open trench method. All plowing and trenching shall be performed in a uniform alignment with the right of way. If the installation of the facility is found to deviate from the approved location, the district, at its sole discretion, may require the adjustment of the facility to the approved location. The utility facility shall be located as set forth in §21.37(b) of this subchapter.

      4. (D) Aboveground appurtenances.

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

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

            1. (I) the installation will not hinder highway maintenance operations;
            2. (II) the housing will be placed at or near the right of way line;
            3. (III) the installation will not reduce visibility and sight distance of the traveling public;
            4. (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;
            5. (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;
            6. (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
            7. (VII) the installation will be compatible with adjacent land uses.
      5. (E) Manholes. Manholes serving electric and communication lines shall conform to the requirements of this section.
      6. (F) Abandonment. Underground electric lines may be abandoned in place at the discretion of the district.

   2. (2) Underground communication lines.

      1. (A) Longitudinal. The minimum depth of cover for cable television and copper cable communications lines shall be 24 inches. The minimum depth of cover for fiber optic facilities shall be 42 inches. If the owner/operator of a fiber optic facility waives damages and fully indemnifies the department in a form acceptable to the department, the minimum depth of cover may be reduced to not less than 36 inches.

      2. (B) Crossings.

         1. (i) The minimum depth of cover for cable television and copper cable communication lines shall be 24 inches under ditches or 18 inches beneath the bottom of the pavement structure, whichever is greater.
         2. (ii) The top of the fiber optic facility shall be placed a minimum of 42 inches below the ditch grade or 18 inches below the pavement structure or 60 inches below the top of the pavement surface, whichever is greater. The department may authorize a minimum depth of cover of not less than 36 inches below the ditch grade or 60 inches below the top of the pavement surface, whichever is greater, if the owner/operator waives damages and fully indemnifies the department in a form acceptable to the department.

         3. (iii) The department may require encasement or other suitable protection when necessary to protect the highway facility when the line is located:

            1. (I) at less than minimum depth;
            2. (II) near the footing of a bridge or other highway structure; or
            3. (III) near another hazardous location.
         4. (iv) Unless the line is encased, installation shall be accomplished by boring a hole the same diameter as the line. The annular void between a drilled hole and the line or casing shall be filled with a material approved by the district to prevent settlement of any part of the highway facility over the line or casing.
      3. (C) Installation. Lines may be placed by plowing or open trench method and shall be located on uniform alignment with the right of way and as near as practical to the right of way line to provide space for possible future highway construction and for possible future utility installations.

      4. (D) Multiple conduits.

         1. (i) Shared conduits. When an existing utility rents, leases, or sells conduit usage to another utility, the new utility and the conduit owner must jointly submit a use and occupancy agreement before placement of a new line within the conduit.
         2. (ii) Additional conduits. No more than two additional empty conduits may be added for every full conduit line, unless otherwise approved by the district.

      5. (E) Aboveground appurtenances.

         1. (i) Aboveground pedestals or other utility appurtenances installed as a part of an underground communication line shall be located at or near the right of way line, so as not to impede highway maintenance or operations.

         2. (ii) Large equipment housings. Structures that are larger in plan view than single poles may be placed on the right of way if:

            1. (I) the installation will not hinder highway maintenance operations;
            2. (II) the housing will be placed at or near the right of way line;
            3. (III) the installation will not reduce visibility and sight distance of the traveling public;
            4. (IV) the dimensions of the housing are minimized, particularly where the need to allow space for highway improvement and accommodation of other utility lines is apparent;
            5. (V) outside width, length (longitudinal), and height dimensions of the aboveground portion of the housing do not exceed 36 inches, 60 inches, and 54 inches respectively;
            6. (VI) the supporting slab does not project further than three inches above ground line, nor extend further than 12 inches on either side of the housing structure; and
            7. (VII) the installation will be compatible with adjacent land uses.
      6. (F) Abandonment. Underground communication lines may be abandoned in place at the discretion of the district.

Source Note:The provisions of this §21.40 adopted to be effective March 17, 2005, 30 TexReg 1455; amended to be effective December 11, 2008, 33 TexReg 10064.