| (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.
Cont'd... |
