CHAPTER 6 - UTILITIES 6.1 INTRODUCTION This chapter establishes criteria fr the design f all relcatins t achieve maintenance, supprt, cntinued service r mdificatin f existing utilities that will be affected by the cnstructin f the system. The criteria als gvern the design f utilities that may be installed n DART right-f-way t prvide utility services t DART s facilities. "Utilities" are defined as the lines, cnnectins and appurtenances frming a transmissin, distributin, cllectin r cmmunicatin system belnging t gvernmental agencies, public utility crpratins, railrads and privately wned cmpanies fr the prvisin f sewer, water, gas, electrical, telephne, telegraph, and cable televisin service. Other systems t be included as utilities are street lighting; petrleum pipelines; fire and security alarm systems; vaults; parking meters; pstal service facilities; railrad lines and equipment and ther cmmunicatins systems. Included are service cnnectins t adjacent prperties and DART-wned utility facilities r cmmunicatin systems. Fr purpses f prviding requirements prvided in this chapter t existing systems, strm sewers and drainage appurtenances will be cnsidered a utility, in as much as these requirements are nt prvided in Chapter 7 - Drainage. Terms used in this chapter are intended t have the fllwing meaning: "Facilities" - Includes "utilities" as described abve. May als include ther structures r systems, depending n usage. "Owner" - The wner f the utility system r systems in questin. The term "utility wner" may als be used fr clarity. DART will be cnsidered the wner if the utility in questin belngs, r will belng t DART. "Railrad, railrad cmpany", r the like" - Used t define railrad cmpanies wnership instead f the term "wner". "City" - Used t define a municipality's wnership f items that are traffic and transprtatin related, as ppsed t utility type items, such as streets and bridges, street lighting, and traffic signalizatin. The required design and cnstructin f utility relcatins due t the impact f DART cnstructin will be perfrmed either under cntracts directly with DART r entirely by the Nv Rev 10-6-1 - Cpyright DART, all rights reserved,
affected facility wner. The designer will be required t prepare designs f utility relcatins nly as specifically directed by DART. These criteria fr utilities relcatins shall be used by the designer nly t the extent f designing thse facilities specifically directed by DART in the `Scpe f Wrk' f the cntract. The criteria prvided herein are intended t cmply with and supplement, relative t DART systems cnstructin, the applicable City cdes, rdinances, regulatins, standards and specificatins fr utility relcatins and cnstructin. Such City standards shall include the Standard Specificatins fr Public Wrks Cnstructin published by the Nrth Central Texas Cuncil f Gvernments, lcal amendments theret, standard details, cnstructin methds, and design plicy and prcedures f the City. Utility wner standards and criteria that equal r exceed these criteria shall gvern. Specific criteria prvided herein shall be in additin t utility wner criteria and standards, and shall gvern in the absence f applicable criteria issued by the utility wner. In the perfrmance f utilities relcatins, cnsideratin shall be given t the needs f the utility system, the requirements and bligatins f the utility wners, traffic requirements, the service needs f adjining prperties, and plicies established, r t be established, by DART. Such cnsideratin shall als include making the fllwing determinatins accrding t criteria prvided in Systems Design Criteria Chapter 8 - Crrsin Cntrl and Chapter 9 - System Grunding: Utilities which d nt generate electrmagnetic interference (EMI) r any ther interference that wuld cmprmise either peratins r safety f any element f the system. Metallic pipes and casings are prtected against crrsin by the use f crrsin-resistant materials, prtective catings, and/r cathdic prtectin, and are made electrically cntinuus in accrdance with the requirements f Systems Design Criteria Chapter 8 - Crrsin Cntrl and Chapter 9 - System Grunding and the crrsin cntrl standard and directive drawings. Utility system design cvered by these criteria shall be crdinated with Systems Design Criteria Chapter 8 - Crrsin Cntrl. DART-wned utility structures may require atmspheric, sil and water, and/r stray current crrsin-preventin measures. Utility cmpany structures shall be designed and cnstructed in accrdance with each cmpany's standard crrsin cntrl practices and the prvisins f any agreements between DART and the utility wners. 6.1.1 Relcatin Alternatives Nv Rev 10-6-2 - Cpyright DART, all rights reserved,
The necessary relcatin f utilities shall be perfrmed by using ne f the fllwing alternative prcedures: Supprt and maintain impacted utility in place during cnstructin f DART s facility, and cntinue in service fllwing cmpletin f the DART system facilities. Temprary relcatin and maintenance, then, upn cmpletin f the DART system facilities, restratin f the existing facility. Temprary relcatin and maintenance, then, upn cmpletin f the DART system facilities, replacement with a new utility facility. Permanent utility relcatin beynd the DART cnstructin limits, preferably clear f the DART right-f-way. Replacement with a new utility facility t be supprted and maintained-in-place during DART s cnstructin, then cntinued in service fllwing cmpletin f the DART system facilities. N relcatin f utilities shall be dne within DART subways with the exceptin f DARTwned facilities such as fire mains and chilled water mains. Utilities service t adjining prperties shall nt be interrupted withut permissin f the facility wner, and, if temprarily relcated, shall be restred upn cmpletin f cnstructin. 6.1.2 Replacements and Relcatins Design Design f replacement r relcatin f utility facilities shall be perfrmed generally n a replacement-in-kind basis. Hwever, the minimum replacement r relcatin standards and design prcedures agreed t by DART and each wner, as listed in Sectin 6.4, shall gvern. If betterments are t be included, they shall be apprved by DART in accrdance with cperative and detailed agreements with the applicable agency, utility, r railrad. All design invlving utility relcatins and replacements will include maintenance f service, supprt in place, replacement due t damage and crdinatin f ther utilities wrk and all designs shall fllw the utility wner's design criteria and specificatins. The designer shall crdinate their wrk and submit utilities replacement and relcatin designs and plans fr review and apprval by DART in accrdance with their cntract and the terms and cnditins f the cperative agreements between DART and the utility wner. Detailed prcedures fr crdinating with the utility wner will be as established by DART. The designer shall Nv Rev 10-6-3 - Cpyright DART, all rights reserved,
crdinate their wrk with the ther designers f adjacent sectins, agencies, utility wners, and private develpers t ensure cmpatibility f the respective replacements r relcatins. Specificatins and design standards prvided by the utility wners knwn t be affected shall be btained directly frm them by the designer. The designer shall crdinate the lcatin f existing utilities and the new prpsed utilities with the DART facility r related cnstructin. It is cmmn practice, in the preparatin f cntract drawings, t specify cntrl elevatins fr nly thse utilities that are dependent n prper slpes fr their peratin, such as gravity sewers. Such practices in the design f the system may result in undergrund facilities cnflicts nt reslvable by field engineering. Pssible surces f cnflict include tw r mre f the fllwing facilities: ftings; sanitary and strm sewers; water, gas, and il lines; cnduits fr train cntrl, cmmunicatins, and auxiliary pwer systems; cnduits fr the tractin pwer system; DART electric service ducts; underdrains; retaining wall stems and cunterfrts; manhles and pull bxes; and structure walls. Elevatins f all utilities shall be crrected t the datum f the U.S. Cast and Gedetic Survey. Where critical t the design, utilities shall be expsed t verify elevatins. In particular, the elevatins f the inverts f all new manhles and ductbanks shall be clearly shwn n the plans and prfiles at the center f the manhle and at the break pints alng the ductbank r at the manhle r junctin bx, respectively. Other critical elevatins and dimensins shall als be highlighted n the plans r prfiles t ntify the Cntractr f any special cnditins. Wherever there is a ptential undergrund facilities cnflict in the system, and where required by utility wners, the designer shall design t eliminate the cnflict and shall indicate sufficient elevatins and hrizntal dimensins s that the design is effectively implemented in the cnstructin. Wherever inclusin f the abve data r the number f utilities invlved results in the plans becming cngested r difficult t interpret, separate drawings shall be prepared fr each utility wner's facilities. Separate utility drawings will be prepared fr City-wned utilities in accrdance with the City's plicies, design criteria, standards and prcedures. Plans prepared fr City-wned utilities and drainage facilities will be prepared in accrdance with the City's requirements, as published in design manuals, develpment guidelines, standard cnstructin details, standard specificatins, and related dcuments. 6.1.3 DART Service Cnnectins Utilities service cnnectins t DART facilities shall be shwn n the utilities plans; their design shall be crdinated with ther items f the wrk. The designer shall ensure that service Nv Rev 10-6-4 - Cpyright DART, all rights reserved,
cnnectins frm the utility mains are indicated n either their plans r thse fr the adjacent cnstructin cntracts t preclude the cutting f new pavement. 6.2 DART UTILITY DESIGN CRITERIA The fllwing sectin is general criteria t be used by the designer in the preparatin f cnstructin plans fr new utilities and the relcating r replacing f existing utilities parallel t, cntiguus with, r acrss and either n, belw r abve the surface f DART s right-f-way. The first part f this sectin discusses requirements fr all utilities related t DART s right-fway. The secnd part f this sectin discusses in detail the undergrund utilities, the verhead utilities and surface utilities. 6.2.1 General Categries Utilities relcatins r replacements are classified int three categries: 1) utilities crssing DART trackways: 2) utilities n DART right-f-way clear f tracks; and 3) utilities clear f DART right-f-way. Utilities Crssing DART Trackways. Utility crssings f DART system trackways, radways, and parking lts shall be kept t a minimum. Crssings under special trackwrk shuld be avided, if pssible. Utilities service cnnectins, ther than thse serving DART s system facilities, shall nt crss beneath system at-grade tracks. Hwever, prperly cnstituted and franchised utility agencies and licensees have the right t crss system rights-f-way with transmissin and distributin/cllectin facilities t fulfill their existing service bligatins. Utilities crssings shall be perpendicular t the DART s system trackway r radway alignment, r as nearly perpendicular as pssible. Utilities shall nt be placed within drainage culverts, r in any manner r psitin that might cause damage t, r impair the safety f the facility r the system. Existing utilities within the system right-f-way shall be relcated t the extent necessary t cnfrm t the criteria prescribed herein, unless specifically excluded frm this requirement by DART and the utility wner. New utilities crssings under perating DART s system trackways shall be made by bring, jacking, r tunneling, and shall be subject t DART apprval in each case. Open-trench methds may generally be used under streets, parking lts, and aerial structures. T facilitate maintenance peratins, utility markers shall be prvided t indicate the lcatin f undergrund utility lines, drainage lines, and appurtenances beneath at-grade tracks. Sectin 6.3, Utility Markers, f this chapter utlines design details and requirements fr utility markers. Nv Rev 10-6-5 - Cpyright DART, all rights reserved,
Flammable r hazardus liquid r gas lines crssing the trackways shall have a valve at each end f the line at the right-f-way fr shutff in emergencies. Utilities may exist n, r be relcated t crss the right-f-way fr subway, at-grade, r aerial trackways. Such utilities may pass abve r beneath the DART facilities. Undergrund utilities relcatins abve subways shall be designed accrding t Sectin 6.3, Design Criteria fr Undergrund Utilities. Thse beneath subways shall be encased as prvided in the utility wner's standards r criteria, r as prvided in the DART standard drawings. The designer shall perfrm their designs s that utilities service will be maintained when required by the facility wner. When practicable, the existing facilities shall be maintained cmplete-in-place. Utilities n DART Right-f-Way Clear f Tracks. Utilities extending lngitudinally alng the trackway shall be limited t thse serving DART s facilities. Facility relcatins clear f tracks but within thedart right-f-way may be allwed in sme instances. When utilities exist within the DART right-f-way and the mst feasible and ecnmical slutin wuld be t supprt r relcate the facility within the right-f-way, the designer shall submit cnceptual schematic designs t DART fr apprval prir t beginning f detailed facility design. Such designs shuld preclude future disruptin t DART peratins. These general criteria gvern the design f relcatins f utilities that are affected by the DART system and that will be relcated in public r private prperty clear f the DART right-f-way r beneath DART parking lts. The design f facility relcatins shall be n a replacement-in-kind basis. It is with the understanding that any upgrading in a replacement facility resulting slely frm the replacement f devices r materials n lnger regularly manufactured, prcessed, r installed shall be cnsidered as a replacement-in-kind. This is based n prvisins that such replacement shall be nly t that standard used n ther prjects financed slely by the utility wner. Minimum replacement standards and methds f design shall be in accrdance with the criteria f the utility wner, and as agreed by DART and each facility wner r, fr a facility that is t be supprted in place during system cnstructin, the standards must be sufficient t prvide required structural strength. Shuld a utility wner require the upgrading f a facility beynd the standard described abve, such upgrading shall cnstitute a betterment and shall nt be included in the wrk prir t an agreement being reached between DART and the utility wner. Nv Rev 10-6-6 - Cpyright DART, all rights reserved,
Facilities clear f DART right-f-way shall be supprted r relcated t facilitate system cnstructin and meet the requirements f facility wners. The designer shall crdinate their wrk with all affected utility wners s that the mst ecnmic verall slutin is btained accrding t these requirements. These facilities als include thse crssing railrad trackways. 6.3 DART DESIGN CRITERIA FOR UNDERGROUND UTILITIES The design criteria fr undergrund utilities will include utilities that will crss, parallel r clear f the DART right-f-way. These utilities will cnsist f strm sewers, sanitary sewers, water mains, gas lines, and petrleum lines. There are several general requirements related t the undergrund utilities, which need t be addressed as fllws: Utilities wires r cables installed in cnduits crssing under at-grade r subway structures shall be placed in plastic r ther apprved nnmetallic cnduits such as Ply Vinyl Chlride (PVC). The cnduits shall be encased in cncrete in accrdance with the utilities standards. The utility wner may perfrm the design and installatin f encased utility relcatins. In this instance, the designer shall prvide the wner with plans f the DART facilities and shall crdinate their wrk with that f the utility wner t ensure that the design cnfrms t these criteria. The designer shall crdinate the design f the encased utility with ther affected facility wners where necessary and shall include the relcatin in the utilities plans and cnstructin sequence plans. Pipelines crssing under aerial structures need nt be placed in casings unless there is danger f damage t the DART facilities. Even if such a danger exists, casings may be mitted if the design f the carrier pipe is specifically apprved by DART in each case. Pipelines crssing under at-grade sectins f the system r beneath subways shall be placed in casings as shwn n the utility wner's standards r minimum standards established by DART. Excluded frm this requirement are strm sewers that nrmally perate under intermittent r cntinuus pressure f less than 10 psi. Cnstructin f casing will be in accrdance with the utility wner s standards. The space between casings and carrier pipes shall be plugged s as t prevent the frmatin f a waterway under the trackway, and casings shall be installed with an even bearing thrughut their length. Installatin f pipeline crssings by pen-trench methds shall cmply with the requirements fr cnduit bedding and backfilling as cntained in the utility wners standards, r minimum standards established by DART. Nv Rev 10-6-7 - Cpyright DART, all rights reserved,
If n casing is required, bred r jacked installatins shall have a bred-hle diameter essentially the same as the utside diameter f the apprved carrier pipe. If vids shuld develp r if the bred-hle diameter is greater than the utside diameter f the casing r apprved carrier pipe, all vids shall be gruted. Bring peratins shall nt be stpped if such stppage wuld be detrimental t the system. Tunneling peratins shall be cnducted as apprved by DART. If vids are caused by the tunneling peratins, they shall be filled by pressure gruting r by ther apprved methds that will prvide prper supprt. Bring, jacking, and tunneling shall be perfrmed accrding t the utility wners standards r minimum standards established by DART. Shut-ff valves shall be used as mutually agreed t by DART and the utility wner. Other than drainage r sewer lines, accessible emergency shutff valves shall be installed in pipelines n each side f DART s system trackway. Wherever pssible, such shutff valves shall be lcated utside the DART right-f-way. Where pipelines are prvided with valved autmatic cntrl statins at lcatins and within distances apprved by DART, n additinal valves shall be required. Utilities may exist in public right-f-way and n private prperty that will becme part f the right-f-way fr a DART parking lt. When such utilities are encuntered, they will be allwed t remain in place beneath the DART parking lts prvided that: 1) The facility can withstand the cnstructin lading and permanent parking lt lading; 2) The depth f cver ver the facility upn cmpletin f cnstructin will nt be less than the minimum cver allwed by the facility wner, greater than the maximum depth used by the facility wner in its wn cnstructin, and greater than an existing utility cnduit may withstand; 3) The facility is nt lcated beneath majr access rads, r bus stalls; 4) The facility des nt cmprmise reliability, maintainability, r safety; 5) The cables are installed in cnduit; and 6) The cnstructin f the parking lt des nt vilate an existing utility easement, interfere with wners maintenance f utility, r is therwise unacceptable t the utility wner. When a utility facility must be relcated because f parking lt cnstructin, the relcatin may be placed beneath the parking lt, prvided the sectin designer shws it is mre ecnmical than relcatin in the public right-f-way r in right-f-way acquired specifically fr the purpse (and apprved by the wner). Such facility relcatins shall be lcated clear f the parking lt, majr access rads, and bus stalls t minimize pssible future disruptin t Nv Rev 10-6-8 - Cpyright DART, all rights reserved,
the parking lt by utilities maintenance peratins. The criteria used t design utilities relcatins beneath DART parking lts shall be thse used fr the design f each utility. Fr undergrund utilities specific criteria is required by DART and by the individual utility wner. The stricter f the tw criteria shall be used which is either DART r the utility wner s criteria fr each utility. The DART design criteria is as fllws: Excavatin Supprt. Refer t Chapter 16 - Excavatin Supprt fr design f trench excavatin and shring related t all utility facilities. 6.3.1 Strm and Sanitary Sewers The designer is respnsible fr the preparatin f cntract dcuments fr the relcatin f all cnflicting strm and sanitary sewers. Unless DART and the facility wner agree therwise, the design and relcatin f sanitary and strm sewer facilities that cnflict with the system shall be perfrmed withut the use f permanent ejectrs r pumping statins. Sewer facility relcatins shall be designed t cnfrm t the design criteria, standards, and rdinances f the utility wner and applicable regulatry agency requirements. Adequate clsed flumes shall be prvided t handle the flw f sanitary sewers temprarily remved frm service. N sewage shall be discharged int pen trench. Design strm sewers and capacity requirements fr strm sewers, and the design f strm sewer facilities, including the relcatin f existing facilities, shall be perfrmed accrding t the requirements f Chapter 7 - Drainage. Municipal requirements will be incrprated int the design as necessary. Where existing municipal strm sewer facilities crss beneath the DART alignment and must be relcated, the relcated facilities shall be designed t current standards and criteria f the municipality. The pipe size shall be determined by calculating the discharge frm the upstream cntributry area and cnsidering the future develpment trends f the area, as set frth in Chapter 7 - Drainage. The resulting flws shall be used t size the cmplete sewer relcatin. Where relcatin is an extensin f an existing strm sewer, and replacement is nt therwise required, the extensin shall be f similar size and shape and f a hydraulic capacity equal t r greater than the existing pipe. When n additinal flw is added t the strm sewer, cnditins dwnstream f the relcatin need nt be studied. Where increase in flw takes place as a result f cnstructin, cnditins dwnstream shall be evaluated. The extent f this evaluatin shall be determined n an individual basis. Shuld retentin/detentin be cnsidered a slutin t an increased rate f strm water discharge r dwnstream sewer inadequacy, the retentin/detentin facility must be in accrdance with Chapter 7 - Drainage. Nv Rev 10-6-9 - Cpyright DART, all rights reserved,
The Designer shall have the fllwing respnsibilities t: 1) Prvide the sewer utility wner with plans shwing the DART facilities and crdinate with the wner t determine the extent f the system impact upn the sewer facilities. The utility wner shall determine which facilities may be abandned r taken ut f service during the utility cnstructin. The utility wner and the designer shall determine which facilities may be supprted-in-place during utility cnstructin. The utility wner and the designer, thrugh DART, shall decide upn lcatins fr the relcatin f cnflicting sewer facilities that are acceptable t DART, the utility wner, and the wners f ther affected facilities. 2) Prepare the design s that service in sanitary and strm sewer facilities is maintained at all times, except in thse facilities previusly determined t be abandned as a result f cnstructin. 3) Prepare cntract dcuments fr the sewer facility relcatins including thse betterments requested by the wner and agreed t by DART. 4) Crdinate sewer facility relcatins with ther utilities wners and lcal gvernment agencies. 5) Include the sewer facility relcatins in the cnstructin sequence plans. 6) Include prvisins in the design t maintain service t all prperties, which are t remain cnnected t sanitary r strm sewers affected by the cnstructin. The Designer shall als cnsider in his design the fllwing factrs related t strm and sanitary sewers: Lcatin and Cver. The lcatin f sanitary sewers with respect t water supply wells and ptable water lines shall fllw the regulatins f the Texas Department f Health and the criteria and standards f the utility wner. Sanitary sewers shall be lcated with a minimum f 3 feet f cver in areas nt subject t vehicular traffic. N part f a prpsed strm sewer shall be designed within the imprved subgrade f a prpsed pavement. The minimum cver fr strm sewers in areas nt subject t vehicular traffic is 2 feet, althugh greater cver is desirable. Where exceptins t these prvisins are made necessary due t cnnectin t existing lines r fr ther causes, special material r bedding may be required. Design f sanitary and strm sewers utside f DART right-f-way shall cnfrm t the design criteria and standards f the respective lcal public agency invlved. Crss Cnnectins. Physical cnnectins between a public r private ptable water supply system and any sewer, drain, facility, r equipment shall nt be made, except in strict accrdance with applicable plumbing cdes and all lcal r state regulatins pertaining t crss cnnectins. Materials. Materials shall be selected t give best service under lcal cnditins and the requirements f the design. Special cnsideratin shall be given t the character f industrial Nv Rev 10-6-10 - Cpyright DART, all rights reserved,
wastes, pssibilities f septicity, exceptinally heavy external lads, abrasin, infiltratin and exfiltratin, sil cnditins, pipe bedding, and similar prblems. Unless therwise apprved by DART, reinfrced cncrete pipes shall be used fr strm sewers. Vitrified clay, reinfrced cncrete r PVC sewer pipe(s) will be used fr sanitary sewers. Materials shall cmply with utility wners criteria and standards. Size. The minimum allwable diameter fr sanitary sewers shall be 8 inches, 4 inches fr residential services, and 6 inches fr ther than residential services. Sanitary sewer laterals within easements r dedicated right-f-way shall be at least 6 inches in diameter. Slpes. All sewers shall be designed with slpes sufficient t give mean velcities, when flwing full r half full, f nt less than 2.0 feet per secnd t a maximum f 10 feet per secnd based n Manning's frmula. Sanitary sewer velcities shall be determined using a Manning's "n" f 0.013. Optimum flw velcity is cnsidered t be 3.0 feet per secnd, and slpes prducing less than 3.0 feet per secnd shall be used nly with the apprval f the utility wner. Pipe Size Increases. At manhles where a sanitary sewer is increased in size and any pints where a smaller sewer cnnects int a larger sewer, the invert f the larger sewer shall be at a lwer elevatin s that the energy gradient is maintained. T achieve this, pipes shall be installed with the crwns at the same elevatin. Alignment. Sanitary sewer mains shall be designed with straight alignment wherever pssible. Where curved alignments are required, design shall nt exceed the minimum curve radius fr pipe material specified, and shall be in accrdance with the utility wner's standards. Manhles. Manhles shall be installed at the end f each sewer line; at all changes in grade, pipe size, junctins, and intersectins; at changes in alignment, except where an apprved curved alignment is invlved, and at ther lcatins as may be required by the utility wner. Manhle spacing shall be in accrdance with the utility wner's standards and criteria. Manhles and cvers shall be cnstructed accrding t the utility wner's criteria, specificatins and standard details. The invert elevatin f the manhle shall be clearly shwn n the plans and prfiles at the center f the manhle. Other critical elevatins and dimensins shall als be highlighted n the plans r prfiles t ntify the Cntractr f any special cnditins. The designer shall have the ptin t permit precast manhles t be used. The requirements, criteria and details shall be nted n the respective plans and defined in the general ntes fr the precast manhle. Inverted Siphns. If n ther ptin exists, and if apprved by the utility wner, design f inverted siphns shall fllw the utility wners standards and the requirements f the Texas Department f Health. Nv Rev 10-6-11 - Cpyright DART, all rights reserved,
Frce Mains. Frce mains shall be cnstructed f ductile irn r PVC pipe with mechanical r ther apprved jints, r, if apprved by the facility wner, ther materials such as prestressed cncrete cylinder pipe. Sanitary Sewer Flws. Where the design f new sanitary sewers is included in the wrk, such sewers shall be designed accrding t the utility wner's criteria. Cnnectins. Cnnectins t existing sanitary sewers shall be by manhles r ther cnstructin apprved by the utility wner. Drainage Reprt. A drainage reprt fr the design f the strm sewer shall be prepared fr submittal t the lcal gvernment agency having jurisdictin. The reprt shall describe the effect f cnstructin f a sectin f the DART system upn the existing drainage facilities and shall shw that the design cnfrms t the applicable DART and utility wner's plicies, criteria and standards. Fr further details f drainage reprt requirements refer t Chapter 7 - Drainage. Lw Pressurized Pipe. Pipelines included in this sectin are thse installed t carry water, r any ther nnflammable substance, which, frm its nature f pressure, might cause damage escaping n, r in the vicinity f, system prperty. The fllwing casing requirements apply t strm and sanitary sewer lines and waterlines. Water lines relcatins and replacements are discussed in mre detail later in this sectin. Relcatins f strm and sanitary sewer facilities that crss under at-grade system trackways and that nrmally perate under pressures f less than 10 psi shall be designed accrding t prcedures specified herein and by the utility wner. Hwever, the design shall be checked t prvide a safeguard fr the system shuld such facilities becme surcharged during a 100-year-frequency strm (Chapter 7 - Drainage). Nn-encased facilities shall have watertight jints and the capability f serving fr a perid f at least 50 years with minimal maintenance. Reinfrced cncrete pipe meeting ASTM C76 and having "O"-ring rubber gasket jints cnfrming t ASTM C443 will satisfy these requirements. Nnflammable Substance Pipelines. Pipelines cntaining nnflammable substances under lw pressure shall be designed as fllws: 1) Carrier pipe and jints fr lines under system trackways shall be f cmparable type, strength, and material t that required by the utility wner fr direct burial applicatin r by AREMA Manual, whichever is mre stringent. Jints fr carrier pipe perating under pressure shall be push-n, mechanical jints, r welded. Carrier pipes shall be in accrdance with the utility wner's criteria and standards, except where these requirements are mre stringent r have additinal requirements. Nv Rev 10-6-12 - Cpyright DART, all rights reserved,
2) Casing materials shall cnsist f crrugated metal, steel, r reinfrced cncrete pipe, all in accrdance with the requirements prescribed belw. Fr larger r high-pressure mains that require peridic inspectin, and where therwise apprpriate, reinfrced cncrete utilities tunnels may be used. The standards f the utility wners shall be cmplied with when mre restrictive r stringent. 3) Crrugated metal casing pipe requirements shall be designed accrding t the latest editin f Crrugated Metal Pipe Culverts - Structural Design Criteria and Recmmended Installatin Practices, published by the Federal Highway Administratin. Fr water mains and sanitary sewer casings, the standards f the utility wner fr crrugated metal pipe and circular liner plate shall be used. 4) Steel casing pipe requirements shall have a minimum yield strength f 35,000 psi. Wall thickness fr steel casing pipe with a prtective cating installed in a trench shall cnfrm t Table 6.1. The wall thicknesses shwn in Table 6.1 shall be increased by at least 0.063 inch fr uncated casing and by at least 0.063 inch fr cated r uncated casings t be installed by jacking r bring. Fr water mains and sanitary sewer, the standards f the utility wner will be used, subject t apprval by DART, in lieu f the freging. 5) Reinfrced cncrete pipe and fittings requirements shall cnfrm t the requirements f ASTM C76, Class IV, minimum, in accrdance with the wner's standards. "O"-ring gaskets shall cnfrm t the requirements f ASTM C443. 6) Casing pipe and jints shall be designed t withstand the impsed lading. Casings shall be slped t drain. They shall be prtected against crrsin in accrdance with the requirements f Systems Design Criteria Chapter 8 - Crrsin Cntrl and Chapter 9 - System Grunding and crrsin cntrl standards and directive drawings. Care shall be taken t select materials that will nt be damaged thrugh dissimilar metals cntact. Where bth carrier pipe and casing are metallic, they shall be separated electrically by using insulated spacers. The inside diameter f the casing shall be at least 2 inches greater than the largest utside diameter f the jint r cupling f the carrier pipe and shall als meet the requirements f the utility wner. In any case, the casing shall be large enugh t allw pressurized carrier pipe t be remved subsequently withut disturbing the casing pipe r trackbed. Fr water main and sanitary sewer casing pipes, the standards f the utility wner will be used. Fr sanitary sewer lines, vids between the encasement and carrier pipes shall be gruted. 7) The ends f the casing shall be suitably sealed t prtect against the entrance f freign materials. Utility wner's standard details fr seals and drainage shall be used. 8) The limits f the casing pipe unless therwise apprved by DART and the utility wner, casing pipe shall extend t the greater f the fllwing hrizntal distances, measured perpendicular t the centerline f track: a minimum distance f 2 feet utside the fenced prtin f the system right-f-way r minimum distance f 25 feet frm the centerline f the utside track. Nv Rev 10-6-13 - Cpyright DART, all rights reserved,
9) If additinal tracks are cnstructed in the future, the casing shall be extended crrespndingly. Where future additinal tracks are planned, utilities shall be installed n a straight line and grade fr the apprpriate distance t facilitate future casing extensin. 10) Minimum cver ver uncased pipe r ver casings shall be 3 feet at areas subject t vehicular traffic, unlined ditches, and ther unpaved surfaces, and 2 feet at lined ditches. Additinal cver shall be prvided where necessary t cmply with the utility wner's plicy r lcal gvernment rdinances. On at-grade DART trackways, the minimum clearance between the tp f uncased pipe r tp f casing pipe and the base f the system rails shall be 4 feet 6 inches. The standards f the utility wners will be used if mre stringent than the abve. 11) Sewer services shall be in accrdance with the cdes and standards f the utility wner. TABLE 6-1 MINIMUM WALL THICKNESS FOR STEEL CASING PIPE UNDER DART TRACKWAYS NOTE: Fr Cated Casings Installed in a Trench Height f Cver Diameter in inches in Feet 10 r less 11 t 20 21 t 30 12 r less 0.250" 0.250" 0.250" 14 0.250" 0.250" 0.250" 16 0.250" 0.250" 0.250" 18 0.250" 0.250" 0.281" 20 0.250" 0.250" 0.312" 22 0.250" 0.250" 0.344" 24 0.250" 0.281" 0.344" 26 0.250" 0.312" 0.375" 28 0.250" 0.312" 0.406" 30 0.250" 0.344" 0.438" 32 0.250" 0.344" 0.469" 34 0.250" 0.344" 0.469" 36 0.250" 0.375" 0.500" 38 0.250" 0.375" 0.500" 40 0.250" 0.406" 0.562" 42 0.250" 0.438" 0.562" Nv Rev 10-6-14 - Cpyright DART, all rights reserved,
NOTE: Fr water mains and sanitary sewers, the standards f the utility wner will be used, subject t apprval by DART, in lieu f the abve table. NOTE: The abve thicknesses pertain t cated pipe casings installed in a trench. A maximum allwable trench width shall be indicated t assure that trench cnditin lading actually ccurs. If casing is t be installed in an embankment and psitive prjecting installatin is anticipated, maximum allwable deflectin shall be equal t 0.05 f nminal pipe diameter, and wall thickness shall be determined frm Spangler's frmula. 6.3.2 Water Mains Water mains belnging t lcal gvernment agencies will be affected by cnstructin f the system. The sectin designer is respnsible fr the preparatin f cntract dcuments fr relcatin f all cnflicting water facilities nt perfrmed by the utility wner. Unless DART and the facility wner agree therwise, the design and relcatin f water facilities that cnflict with the system shall be perfrmed n a replacement-in-kind basis. Designer Requirements. It shall be the designer's respnsibility t implement the fllwing general requirements fr the relcatin r replacement f water mains and service lines: 1) Prvide the water utility wner with plans shwing the DART facilities and crdinate with the wner t determine the extent f the system impact upn the water facilities. The utility wner and the designer shall determine which facilities may be abandned r taken ut f service during DART system cnstructin and which facilities may be supprted-in-place during system cnstructin. All water mains with lead jints shall be replaced with ductile irn r PVC pipe having mechanical r push-n jints prir t supprting-in-place. The utility wner and the designer shall decide upn the lcatins fr the relcatin f cnflicting water facilities which are acceptable t DART, the facility wner, and the wners f ther affected facilities. 2) Prepare the designs s that water service is maintained at all times, except in thse facilities previusly determined t be abandned as a result f the recnstructin. N water main r fire hydrant shall be ut f service withut prir apprval f the utility wner. 3) Prepare cntract dcuments fr the water facility relcatins, including thse betterments requested by the wner and agreed t by DART. 4) Crdinate water facility relcatins with ther utilities wners and lcal gvernment agencies. 5) Include the water facility relcatins in the DART cnstructin sequence plans. Nv Rev 10-6-15 - Cpyright DART, all rights reserved,
The designer shall incrprate int the plans the fllwing design requirements fr the fllwing specific items and elements related t the relcatin r replacement f water mains and service lines. 1) Water mains, materials and fittings shall be as required by the wner. Relcatin alignments must meet the current standards f the utility wner. 2) Depth f cver shall be 4 feet minimum n DART right-f-way r prperty, and in accrdance with the utility wner's criteria in all public right-f-way, DART right-f-way, r utility easement. 3) Fire hydrant installatin shall cmply with the utility wner's standards. The sectin designer shall cnsider bth temprary and permanent requirements when designing hydrant relcatins. The fllwing pertains t fire hydrant installatin: a) Spacing: Residential and cmmercial/central business district areas: Hydrant spacing shall fllw utility wner and lcal fire department requirements. DART statins and ther DART facilities: Hydrant spacing shall fllw the requirements specified in Chapter 29 - Fire Prtectin Systems. DART yard facilities: Hydrant spacing shall be a maximum f 300 feet. b) Valving fr hydrants: Hydrants shall be installed n a 6-inch lateral and shall have a 6-inch gate valve lcated between the hydrant and the main. c) Bracing: Hydrants shall be anchred in accrdance with the utilities standards. 4) Valve type and spacing shall be in accrdance with the utility wner's criteria and standards. 5) Thrust blcks r apprved jint restraint systems shall be prvided at bends (hrizntal and vertical), tees, and plugs accrding t the utility wner's criteria and standard details. 6) Casings are required fr all water mains crssing under DART tracks. Crssings under DART trackways shall cnfrm t casing requirements detailed under Strm and Sanitary Sewers. 7) Crssings under ther facilities shall cmply with the standards and criteria f the specific facility wner. Where the facility must remain in peratin, the use f tunneling r jacking shall be cnsidered fr the installatin f relcating facilities crssing belw. 8) Services taps n new, relcated and replaced water mains shall be installed accrding t the requirements f the utility wner. 9) All cleaning, pressure and leakage tests, and chlrinatin fr disinfectin requirements shall be in cnfrmance with the criteria f the utility wner. 10) Water mains n bridge crssings r structure shall cmply with the fllwing requirements: Nv Rev 10-6-16 - Cpyright DART, all rights reserved,
a) All pipe jints that are t be aerially supprted ver r under a bridge r similar structure shall be thrughly restrained against bth lngitudinal and lateral mvement with a minimum f ne restraining device per jint. b) Pipe material shall be ductile irn r steel and in accrdance with utility wner's requirements. c) Each crssing shall have a valve n each side f the bridge and beynd the abutment lcated in prximity t the crssing. Valves shall nt be n the bridge structure. 11) Blw-ff valves, air vents r air/vacuum release valves shall be prvided when directed by the utility wner, and shall be in accrdance with the utility wner's criteria and standards. 12) Pipe insulatin, if required fr aerially supprted r ther abve grade lines, shall meet r exceed insulatin equivalent t the fllwing, and apprved by the wner: a) Insulating material: 3-inch-thick plyurethane pipe cvering, frmed t fit the particular pipe diameter. b) Outer cvering material: 0.016-inch aluminum chiller jacket with misture shield secured with stainless steel straps. 13) Right-f-way fr publicly wned water facilities shall never be placed n private prperty. Shuld the area within the public right-f-way be insufficient fr facility installatin, sufficient right-f-way r an easement shall be prvided. 14) Cnnectins t water main shall be shwn n the plans. The designer shall prepare plans shwing details fr the cnnectin f new, relcated r replaced water mains t the existing mains. Such details shall include valves, temprary hydrants, fittings, and temprary and permanent plugs. The cnnectin plan shall delineate the fllwing respnsibility fr perfrmance f the wrk: unless specified therwise, all water main cnnectins shall be cnstructed by the cntractr after necessary valve peratin by the utility wner. 15) Service Cnnectins shall be shwn n the plans. Cmmercial and industrial service cnnectins 4 inches and larger shall be detailed n the plans. Residential service cnnectins shall be included by reference n the drawings. Respnsibilities fr relcatin f service cnnectins shall be in accrdance with the utility wner's standard prcedure and criteria. 16) Water services and meters shall be installed accrding t the cdes and standards f the utility wner. 17) DART fire and dmestic water service cnnectins shall be designed by the designer. The size f the dmestic cnnectin and meter shall be based upn peak-demand/pressure lss calculatins in cnjunctin with lcal cdes and rdinances. Fire flw and pressure data in the existing water main shall be btained frm the water utility wner. 18) The fire and dmestic services in public right-f-way and up t the DART right-f-way shall be installed by DART's cntractr. The dmestic service meter must be in public Nv Rev 10-6-17 - Cpyright DART, all rights reserved,
right-f-way r in a utility easement granted by DART t the water utility. The utility will install all dmestic meters, and either the utility r DART's cntractr may install fire service meters. 6.3.3 Gas Facilities The designer shall cmply with the fllwing general requirements as they relate t gas lines and facilities. These requirements will als apply t petrleum lines and lines which carry flammable and highly vlatile substances. The designer shall pay clse attentin t the facilities wner s requirements in the design f the relcatin r replacement f these lines. Pipelines fr Flammable Substances. Pipelines included in this sectin are thse installed t carry natural gas, il, petrleum prducts, r ther flammable r highly vlatile substances. They shall be encased under DART tracks and right-f-way in accrdance with the fllwing criteria: 1) Carrier pipe: a) The fllwing requirements fr carrier pipe apply t pipelines crssing under bth at-grade and aerial sectins f the system. These requirements apply fr a minimum hrizntal distance f 50 feet frm the centerline f the utside track r 25 feet beynd the end f casing when casing is required whichever is greater. b) Pipelines carrying il and ther flammable prducts shall cnfrm t the requirements f the current editin f ANSI B31.4, Liquid Petrleum Transprtatin Piping Systems, and ther applicable ANSI cdes. c) Wall thickness fr carrier pipe shall be based n the design criteria, standards, and specificatins used by the facility wner fr encased crssings beneath highways r railrads. In n case shall the encased facility be f lesser strength than the adjacent, direct-burial sectins. 2) Casing materials: Casing pipe and jints shall be f crrugated metal, steel, ductile irn, r reinfrced cncrete pipe accrding t the requirements prescribed fr nnflammable carrier pipe, excluding plastic pipe. Fr large r high-pressure mains that require peridic inspectin, reinfrced cncrete utilities tunnels may be used. 3) Casing design: Casing pipe and jints shall be watertight and shall be capable f withstanding the impsed lading. Casings shall be slped t drain. They shall be prtected against crrsin in accrdance with the requirements f Systems Design Criteria Chapter 8 - Crrsin Cntrl and Chapter 9 - System Grunding chapter and the crrsin cntrl standard and directive drawings. Care shall be taken t select materials that will nt be damaged thrugh dissimilar metals cntact. Where bth carrier pipe and casing are metallic, they shall be separated by using insulated spacers. The inside diameter f the casing shall be at least 2 inches greater than the largest utside diameter f the jint r cupling f the carrier pipe. The casing diameter shall always be large enugh t allw the carrier pipe t be remved subsequently withut disturbing the casing Nv Rev 10-6-18 - Cpyright DART, all rights reserved,
pipe r trackbed. All jints r cuplings, supprts, insulatrs, r centering devices fr the carrier pipe within a casing shall be taken int accunt. In additin, casing shall be designed s that its maximum vertical deflectin is 5 percent f its diameter and s that n lads frm the trackbed, track, traffic, r casing pipe itself are transmitted t the carrier pipe. 4) Ends f casings and vents: a) The ends f casings shall nt prject abve grund level. They shall be clsed with a liquid-tight seal bushing r bulkhead. b) Casing pipe shall extend t the greater f the fllwing hrizntal distances, measured perpendicular t the centerline f track, unless therwise apprved by DART and the utility wner: A minimum distance f 2 feet utside the fenced prtin f the DART right-f- way. A minimum distance f 25 feet frm the centerline f the utside track, when the casing is sealed at bth ends. c) If additinal tracks are cnstructed in the future, the casing shall be extended crrespndingly. d) Casings shall be vented at each end by vent pipes attached near the ends f the casing and having a minimum diameter f 2 inches. Vents shall prject thrugh the grund surface utside the DART right-f-way at a distance f nt less than 6 inches frm the right-f-way line r nt less than 25 feet measured at right angles frm the centerline f the nearest track, unless therwise apprved by DART and the utility wner. e) Vent pipes n DART right-f-way shall extend nt less than 4 feet abve the grund surface. The tp f the vent pipe shall be fitted with a dwn-turned elbw that shall be screened r fitted with a relief valve. Vents in lcatins subject t high water shall be extended abve the maximum elevatin f high water and shall be adequately supprted and prtected. f) Vent pipes n DART right-f-way shall terminate at least 8 feet belw aerial electric wires carrying 750 vlts r less and 12 feet belw aerial electric wires carrying ver 750 vlts. 5) Cver: Minimum cver ver uncased pipe r ver casings shall be 4 feet in areas subject t vehicular traffic, unlined ditches, and ther unpaved surfaces, and 2 feet at lined ditches. Additinal cver shall be prvided where necessary t cmply with the facility wner's plicy r lcal design cnditins. On at-grade trackways, the minimum clearance between the tp f encased pipe r tp f casing pipe and the base f the system rails shall be 5'-6". Natural gas transmissin and distributin facilities belnging t the gas cmpanies will be affected by cnstructin f the system. The gas cmpanies, crdinating thrugh DART and Nv Rev 10-6-19 - Cpyright DART, all rights reserved,
ther facility wners, shall decide upn lcatins fr the relcatin f affected gas facilities that are acceptable t DART, the cmpanies, and ther affected facility wners. Unless DART and the gas cmpany agree therwise, the design and relcatin f gas facilities that cnflict with the system shall be perfrmed n a replacement-in-kind basis by the gas cmpany accrding t their criteria and standards, and all lcal, State and federal standards and cdes. Abandned gas pipe lines within DART right-f-way shall be excavated and dispsed f after they have been purged by the gas cmpany. Designer Requirements. It shall be the designer's respnsibility t: 1) Prvide the gas cmpany with plans shwing the DART facilities. 2) Include the cmpany's requirements fr maintenance f gas facilities cmplete-in-place in the preparatin f the DART design. 3) Include the gas facility relcatins t be perfrmed by the cmpany in the DART cnstructin sequence plans. Gas Cmpany Respnsibilities. The gas cmpany shall crdinate with the designer thrugh DART t determine the extent f the system impact n the gas facilities, and the cmpany shall: 1) Determine facilities where service may be terminated n a temprary r permanent basis. 2) Delineate thse facilities that are t be maintained cmplete-in-place. Facilities that are t be maintained-in-place abve DART subways shall be cnstructed f steel; facilities f ther materials shall be replaced with steel by the gas cmpany prir t system cnstructin. Facilities t be maintained-in-place beneath at-grade DART tracks shall be enclsed in a casing in accrdance with the requirements fr Pipelines fr Flammable Substances. 3) Design and cnstruct new facilities necessary t maintain cntinuity f service t the cmpany s custmers. 6.3.4 Petrleum Prducts Pipelines High-pressure fuel and il transmissin pipeline facilities belnging t different privately wned pipeline cmpanies will be affected by cnstructin f the DART system. The design and relcatin f pipelines that cnflict with the system shall be perfrmed by the facility wner accrding t cmpany standards and all applicable lcal, state, and federal standards and cdes. The general requirements fr pipelines carrying flammable substances shall be implemented n petrleum lines. Nv Rev 10-6-20 - Cpyright DART, all rights reserved,