| (multiplied by longitudinal joint factor) of the pipe as defined in the ANSI codes. (C) Pipelines under railroad tracks and across state railroad right of way property shall be encased. Casings shall extend from right of way line to right of way line unless otherwise approved. (D) Pipelines and casing pipes shall be suitably insulated from underground conduits carrying electric wires on railroad property. (E) Reinforced concrete pipe must be encased for a distance as wide as the embankment at the utility crossing in order to protect against track failure due to joint separation. (4) Encasement of utilities. (A) Casings may be omitted for gaseous products only under the following circumstances. (i) Carrier pipe must be steel and the wall thickness must conform to Cooper E-80 loading for casing pipe shown in the tables included in the AREMA manual Chapter 1, Part 5 for Pipeline Crossings. The length of thicker-walled pipe shall extend from railroad right of way line to right of way line. This will result in thicker-walled pipe on state railroad right of way. (ii) All steel pipes shall be coated and cathodically protected. (iii) The depth from base of rail to top of pipe shall not be less than 10 feet below base of rail. The depth from ditches or other low points on railroad right of way shall not be less than six feet from ground line to top of pipe. (B) In circumstances where it is not feasible to install encasement from right of way line to right of way line, casing pipe under railroad tracks and across railroad property shall extend to the greater of the following distances, measured at right angles to the centerline of the track: (i) two feet beyond toe of slope; (ii) three feet beyond ditch line; (iii) 25 feet from centerline of outside track when casing is sealed at both ends; (iv) 45 feet from centerline of outside track when casing is open at both ends; or (v) if additional track is planned for future construction, casing must extend far enough to meet above distances given the additional track requirement. (C) Pipelines and casing pipe shall be suitably insulated from underground conduits carrying electric wires on railroad property. (D) Casing pipe and joints shall be made of metal and of leak proof construction. Casings shall be capable of withstanding the railroad loadings and other loads superimposed upon them. (E) Wall thickness designations for steel casing pipe for Cooper E-80 loading including impact are as follows: Attached Graphic (i) Steel pipe shall have a minimum yield strength of 35,000 pounds per square inch. (ii) All metallic casing pipes are to be designed for effective corrosion control and long service life and relatively free from routine servicing and maintenance. Corrosion control measures must include cathodic protection. (iii) Cast iron may be used for casing and shall conform to ANSI A21. The pipe shall be connected with mechanical-type joints. Plain-end pipe shall be connected with compression-type couplings. The strength of the cast iron pipe to sustain external loads shall be computed in accordance with the most current ANSI A21.1 Manual for the Computation of Strength and Thickness of Cast Iron Pipe. (F) The inside diameter of the casing pipe shall be such that the carrier pipe can be removed without disturbing the casing. All joints or couplings, supports, insulators, or centering devices for the carrier pipe shall be considered in the selection of the casing diameter. (G) For flexible casing pipe, a minimum vertical deflection clearance of the casing pipe shall be three percent of its diameter plus one-half inch so that no loads from the roadbed, track, railroad traffic, or casing pipe are transmitted to the carrier pipe. When insulators are used on the carrier pipe, the relationship of the casing size to the size of the carrier pipe is as follows: Attached Graphic (5) Casing and pipeline installation. (A) Casing and pipeline installations must be accomplished by directional boring, jack-and-bore, tunneling, or other approved methods. Tunneling construction under tracks will be permitted only under direct supervision of the department. Tunneling procedures and equipment, as well as structural design, must have department approval prior to starting any work on state railroad right of way. Generally, tunneling will not be considered where less than six feet of cover exists, or where excessively sandy, loose, or rocky soils are anticipated. Rail elevations over the work must be monitored at intervals prescribed by the department to detect any track movement. Movements of over one-quarter inch vertically shall be immediately reported to the department. The following requirements shall apply to these construction methods. (i) The use of water under pressure jetting or puddling will not be permitted to facilitate boring, pushing, or jacking operations. Some boring may require water to lubricate cutter and pipe, and under such conditions, is considered dry boring. (ii) Where unstable soil conditions exist, boring or tunneling operations shall be conducted in such a manner as not to be detrimental to the railroad. (iii) If excessive voids or too large a bored hole is produced during casing or pipeline installations, or if it is necessary to abandon a bored or tunneled hole, prompt remedial action shall be taken by the utility. (iv) All voids or abandoned holes caused by boring or jacking are to be filled by pressure grouting. The grout material shall be sand cement slurry with a minimum of two sacks of cement per cubic yard and a minimum of water to assure satisfactory placement. (v) The hole diameter resulting from bored or tunneled installations shall not exceed the outside diameter of the utility pipe, cable or casing including coating, by more than one and one-half inches for pipes with an inside diameter of 12 inches or less, or two inches for pipes with an inside diameter greater than 12 inches. (vi) Pits for boring, tunneling, or jacking will not be permitted within 30 feet of the centerline of the track or closer to the track than the toe of fill slopes in fill sections, or toe of shoulder slopes in ditch sections when pipes are allowed on the railroad property. (B) Vents. In casing pipe installations, vents are appurtenances by which fluids or gases between carrier and casing may be inspected, sampled, exhausted, or evacuated. (i) Vents shall be located at the high end of short casings and at both ends of casings longer than 150 feet. (ii) Vent standpipes shall be located and constructed so as not to interfere with maintenance of the railroad or to be concealed by vegetation. Where possible, they shall be marked and located at the property line. The markers shall give the name and address of the owner, and a phone number to contact in case of an emergency. (iii) Casing pipe shall be properly vented when sealed. Vent pipes shall be of sufficient diameter, but in no case less than two inches in diameter, and shall be attached near each end of the casing, projecting through the ground surface at property lines. (iv) Vent pipes shall extend not less than four feet above ground surface. The top of a vent pipe shall be fitted with a properly screened down-turned elbow or a relief valve. (v) For pipelines carrying flammable materials, vent pipes on casings shall be at least 16 feet vertically from aerial electric wires. Casings shall be suitably insulated from underground conduits carrying electric wires on railroad right of way. (C) Shut-off valves. (i) The utility shall install accessible emergency shut-off valves within effective distances on each side of the railroad track. Where pipelines are provided with automatic control stations, no additional valves will be required. (ii) Shut-off valves may not be placed on the right of way unless approved by the district engineer. If approval is acquired, a guardrail must protect the shut-off valve. (iii) When a guardrail is required, its height shall be four feet above the ground line. All four corner posts shall be driven to a minimum depth of four feet below ground line. There shall be a minimum clearance of two feet from the valve to the guardrail. The steel pipes for the four corner posts and guardrail shall have a minimum diameter of four inches. All joints will be welded with a one-quarter inch fillet weld all around. (6) Water lines. (A) Where casing pipe is used, venting is not required. Sealing will be required if the ends of the casing are not above high water. (B) Where non-metallic pipe is permitted and installed, steel casings are required from right of way line to right of way line. Cont'd... |
