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Vid 12. No. I I'uhlishcd Ik iIh- l ni*lk'H l'N'( l`ipr V^wtmInni, IhilLm, lr\in Sumiwr IW 15 Year Old PVC Sewer Pipe Passes The Tests Of Time h\ Dennis E Bauer Av\<>< laiton Engineer While PVC sewer pipe isn't the only sewer pipe, a certainly is the sewer pipe of choice. You have told us that tighter joints, longer lengths, ease of construc tion and superior performance are all part of your preference for PVC. As an industry, we felt you would he interested in learning just how good your decision was to specify PVC sewer pipe from a durability standpoint. We will endeavor within this article to provide a report card, if you will, of the pipe's ability to withstand the soil environment as well as the sewage effluent. Numerous testimonials to PVC's superior long-term performance are available from users throughout North America. However, they have neither the time, budget nor inclination to dig-up perfectly good PVC sewer pipe to lest its durability. The members of the Uni-Beil PVC Pipe Association appreciate your business and think it very prudent to provide such technical information in support of your selection of PVC. A decision was made in 1988 to locate and remove sufficient PVC sewer pipe to test in accordance with ASTM D 3034. "Standard Specification for Type PSM Pols (Vinyl Chloride) (PVC) Sewer Pipe and Fiiungs.'" The pipe was io be one of the earliest gasketed SDR 35 sewer pipes manufactured in accordance with this standard. ASTM D 3034 was originally published in 1972. Therefore, the oldest pipe, if installed in 1972 and excavated m 1988. would be 16 years old, Certainly an adequate period of time to formulate opinions on long-term durability. There were prerequisites, in addition to it being gasketed SDR 35. established upon which a specific site selection would be based. One of the requirements IN THIS ISSUE. AWWA News................... 1 Chairmans Message........ s Pembroke Pines................ X PVC Time Capsule........... ...j AASHTO Corrections..... ...5 New Members.................. ...6 AWWA Exhibit................. .. 7 Deflection Effects............. ...X Force Mam Desien........... .10 Back to Basics.................. .11 Pressure Pipe. Fittings..... .12 was that the line chosen be at least 10 years old. It should also be a sanitary sewer application, with common slopes, depth of cover and operating conditions. A linal prerequisite was that the project selected be one tor which initial installation documentation was available. This requirement would insure an ability to objectively review the changes with time in the pipe perfor mance as well as durability. Sue Selec non In researching the records for older PVC sewer locations, the City of Dallas. Texas, turned up. Because Dallas has used PVC sewer pipe for many years, a number of sites could be considered. We were interested in knowing what the initial deflections were and (he installation requirements that produced them. Thank goodness we were working with the City of Dallas. They keep very good records, m very good order. And. they were very patient in leading us through ihem. Further review led to a 10 inch diameter gasketed SDR 35 PVC sewer line on the north side of Dallas, which had been installed in May of 1973. The City had plan and profiles of the project with embedment descrip tion as well as a report on initial deflections. Depths of burial ranged from 8 to 10 feet with a planned slope of 0.80 percent. By tapping the collective memory of local manufacturer's representatives, we learned that the manufacturer of this pipe had completed an initial installation report as well. This site had everything we required. But. would the City be willing to cooperate with us on a research project requiring the removal of an active PVC sewer line from beneath a City street. The Dallas Water Utilities tContinued on Pa$e 4) The 10-inch PVC is removed from Dallas. Batavia Breaks Ground With North America's Largest Diameter PVC Pressure Pipe Installation The City of Batavia. New York, has come a long way since its first municipal sewers were installed m 1903. They were, of course, clay tiled. Problem was. the materials had breakage and leaky joints after installation. Batavia s Director of Public Works and City Engineer. Dennis Larson, explains. "This city is built on a flat bog with an unusually high water table. That plus the fact we have numerous hot soil areas contributed to reduced life spans for some of our force mams. In addition, maintenance costs escalated due to leakage problems on the gravity clay tile lines."' As a result, in more recent years. Larson s engineering team began to include poly vinyl chloride (PNC) pipe in its tendering specifications. The reasons arc sound: PVC is unaffected by corrosion: PVC is smooth-wailed and. js such, offers less resistance to waste buildup which can dramatically reduce How capacities. Now in and jround Baiuwa there are miles and miles oi PVC gravity sewer pipes ranging in size trom 6-ms to the large 24 and 3<)-in. diameter mains So. it was to PNC ihai Batavia turned recently The project: To provide large diameter PVC pressure pipe for a new 4.9(81 toot sewer force main cupjble of moving all effluent in the city from a new central pumping station to an also new treatment plant C'fnnnut J mi /x/e< J i Um-Bell PVC Pipe Association 2655 Villa Creek Dove Suite i 55 Oaiias Texas 75234 Mail to: Bulk Bate U S Postage PAJ0 Ptmwi Mil Oaiiaa. T(im CTL027258 r * 1 LmBell-PVC Pipe New* Page 2 AWWA Approves C900 Update; Copies Available In April Chairman's Message The American Water Works Association has recently completed work on the update to AWWA C900. "Standard for Polyvinyl Chloride (PVC) Pressure Pipe. 4 In. Through 12 In . tor Water Distribution." C900-89 has completed all review and approval levels and now awaits only publishing. AWWA association staff cur rently project that the standard update will be available for purchase sometime in April. American Water Works Association procedures provide for the review and update ol all AWWA standards by the committee ol jurisdiction every five years. This ensures appro priateness as well as accuracy. The major change to C900-89. deletion ol provision lor ironpipe-size and solvent welded products, helps demonstrate the wisdom ot the requirement. Although always included in C900. these two product types have never been commercially available Copies of C900-89 will be available for purchase directly from AWWA at 6666 W. Quincy Ave., Denver. CO 80235. AWWA Board of Directors Approves PVC Transmission Pipe Standard The American Water Works Association's (AWWAs) Board of Directors has culminated a four year, standard development effort by approving a standard for PVC transmission pipe. The new standard became effective on December l. 1988. The designation for this standard is AWWA C905. AWWA C905 standardizes PVC transmission pipes in nominal diameters ranging from 14 inches through 36 inches Both (PS and Cl outside dimensioned products are included in the AWWA standard. To enhance design effi ciency at least four different wall thicknesses are provided for each nominal diameter. The specific dimension ratios (DR's) in AWWA C905 are 18. 21. 25. 26. 32.5 and 41 Quality A wut'd CM5 PVC pipes manufactured and tested in compliance uith AWWA C9U5 are capable of providing trouble tree, longer life performance than the con ventional pipe products they are certain to displace Performance assurance begins with stringent material requirements for both pipe and gaskets. Workmanship of the highest quality is also a C905 requirement. Pipe quality is further evaluated through a senes of finished product tests that include dimensional checks, pipe flattening, immersion in anhydrous acetone, joint tight ness and hydrostatic pressure testing of each length of pipe, including the joint. Purchasers of AWWA C905 PVC pipe may specify that the manufacturer furnish an affidavit that all pipe conform to the requirements of C9U5 In addition. Underwriters Labora tories (UL) certification is available for C905 pipe. Water qualit) is assured through certification by the National Sanitation Foundation (NSF). Statc-oj-the-Art P\ C Design Design criteria for PVC transmission pipe are included in Appendix A of AWWA C90.V These criteria represent the latest advances m PVC pipe engineering. The allowable design stress for C905 pipe is conservatively established to accommodate over a trillion years of continuous service. A service life that cannot be compromised by aggressive water or corrosive soil environ ments. AWWA C905 provides for pressure ratings (PR's) ranging FREE Please send me the following information (check information desired): from 100 psi (689 kPa) up to 235 psi (1620 kPa). Surge pressures are properly accom modated on a case-by-case basis in the working-pressure rating (WPR). The appropriate equa tions are included in C905. The design safetv factor of 2 0 recommended in AWWA C905 equals or exceeds that found in other non-PVC AWW A pipe standards. An even larger safety factor of 3 2 is provided tor instantaneous total system pressure. External load design is equally conservative but usually not design limiting tor P\ C transmission pipe. Exemplars Performam e While AWWA C905 repre sents a major standardization advancement, larger diameter PVC pressure pipes are not new to North America. The first larger diameter (nominal 18 inch diameter) PVC transmission pipe was installed in Since (hat time a steadily increasing number ol installations and applications have followed. Most notably, all of the larger diameter PVC transmission pipe installations throughout North America are performing suc cessfully. Prior to AWWAs approval ot C905. our own l ni Bell recommended standard, i e LM-B-II. provided spentier* with an interim product standard. Ohtaimm: hnu C"f* J AWWA C900 .. see arm tc this pave J AWWA COOS .. see arm le this j\jec Zi Handbook Supplement ... see arm le this pave Name CompanyAddress Cm ____ CTL027259 .State____ Zip_ Mail To: Ini-Bell PAC Pipe Association 2655 A ilia Creek Drise. Suite 155 Dallas. Texas 75234 Our readers are crv.(surafed to obtain a copv of aw w a C905 either direitit irom AW'W'A or Irom Lni Bell For your copy, compliments of LniBell, return the coupon -or a copy thereof) locaied `*n page 2 of this issue 'lou are jIm >nv iied to request a tree v.*pv .! our Handbook $uppUmv>u covering large diameter pres'ure pipe design and selcwiion This supplement includes useful hydraulic information specific to PVC pipe complving with AWWAC905 in James K Rush Uni-Hell RiHjrtl Chuiniitm Last year. I his column spoke ol' increasing PVC pipe prices and ihe need 10 develop performance value in Ihe marker place. This year, we are seeing a conunuation ot this trend with some clear signs that PVC pipe is coming into its own as a "product of choice." During the past year, the awareness of all water consumers has raised due to the EPA regulations on lead. This raised awareness placed increased demands on water systems as the public is now crying for purity. Fortunately. PVC piping offers the consumer the opportunity to receive water from the tap as pure as when it left ihe originating water source. PVC pipe is the most heavily regulated product in the piping industry. Included in the many product standards is James K. Rash adherence to the National Sanitation Foundation standards on taste and odor: the only piping product that meets this requirement. As environmental pressures mount, the quality conscious consumer will look to our standard of quality as the yardstick. Thus, our industry has the unusual opportunity of benefiting from environmental pressure. Nevertheless, change is slow and it will take some time for the general populace to fully appreciate the performance value of PVC pipe. We still need to sell our product attributes. AWWA Appoints PVC Committee Recognizing the ever-mcreasing role polyvinyl chloride (PVC) pipe ts experiencing in the water works industry, the American Water Works Association (AWWA) last year announced a committee split. The Thermoplastic Pressure Pipe Commmee had long served as the responsible committee for all PVC and polyolefin products (polyethylene and polvbutylenei PVC now represents sufficient market to warrant a specific committee. Therefore, in June of 88. AW WA Standards Council did vole to split the committee into two new committees. The result is the new PVC Pipe and Fittings Committee and the Polyolefin Pipe and Fittings Committee. Vlr. Joe Richard, who served as Vice-Chairman of the Thermoplastic Pressure Pipe Committee, has been named to chair the PVC Committee. Chief engineer for ihe City of Baton Rouge. Louisiana. Joe is no .(ranger 10 PVC. Consumer esperience comes to him from his dunes at the City of Baton Rouge. General interest expertise is available both through his previous affiliation with the consulting firm of Owen and White and from his continued work as an expert witness in private consultation cases. Producer perspective is also well represented in Joe s resume by previous employment with a PVC pipe producer and his one nme role as chairman of ihe LmBell Technical Commmee. Truly Mr Richard comes 10 the chair having walked a mile in every one s shoes! One other facet of the split is to open the membership to include more specific expertise. AWWA Governing Documents provide that all committees must represent an equal balance in membership from the three categories alluded to earlierconsumer. general interest and producer. The Thermoplastic Pressure Pipe Committee constantly struggled with the compromise of seating enough members to adequately represent all products in all facets of use in all membership categories v ersus seating numbers of members which were unwielding and an obstacle to consensus. The newly seated PVC Pipe and Fittings Committee does currently have positions available for both consumer and general interest, qualified in experience with PVC pipe and fittings. Those qualified applicants willing to serve should offer their desire and background in writing to Mr. Dewey Dickson, Chairman of AWWA Standards Council, with copy to Mr Joe Richard as below: Mr. Dewey Dickson JM Montsomers Enemeers PO. Box 7009' Pasadena. CA 9IUi9 Mr Joe Richard 1068 Colonial Drive Baton Rouge. LA 70X06 Lni-Bell otter- its sr.-re appreciation for those w ho sen eJ so unselfishly for -o lone nr tie Thermoplastics Commmee We now join the entire wjier worts Industry in also offering our Oe-t w ishes to ihe new PS C Commmee I Batavia for an average flow rate of 6 million gafs/day. Peak design capacity is 22 million gals/tlay UniBeil PVC Pipe News Psft 3 \ (ContinuedJmni Pa\>e l) Smith rates the lower coefficient of friction in the pipe The current 14-in. ductile iron main together with the present treatment plant will be phased out of service. For the new line, specified as pressure pipe, the Um-Bril member company recommended its 30-m. SDR 25, introduced to the marketplace in 1987 The pipe meets all industry standards including AWWA C905. "Poly vinyl Chloride (PVC) Water Tran>misMon Pipe. Nominal Diameters 14 In. Through 16 In." and UNI-B-II, "Recom mended Standard Specification lor Polyvinyl Chloride (PVC) Water Transmission Pipe (Nom inal Diameters 14-36 Inch)," and with 32-in. OD. is the largest diameter (PVC pressure) water transmission pipe made in North America. "We felt confident in choosing it. largely on the basis of slickness and flow character istics. and its heavier wall." notes Larson. "Very simply, we were looking for the very best pipe for the job." Pressure rated at 165 psi. SDR 25 weighs 86.58 Ibs/ft and has a wall thickness of 1.280 ins. as crucial. "This means reduced calcification, less buildup." he says. The city's Larson agrees, and goes further by siting PVC * corrosion resistance. "In some areas, ductile iron would have been sufficient. But in many hot spots you get the double problem ot internal and external corrosion. Neither is much of a factor with PVC. We have a lot of faith in that pipe Smith likes it tor one other reason --the high water table in Batavia. "Average depth below the surface grade is onl> eight feet. The force mam was installed at 10 toot depths. You can readily see the potential for problems." he says But not with the PVC pipe. Since it is pressure-rated (including the gaskets), it can withstand higher internal and external pressures-- even when it sits continuously below the water table. As for cost. Smith maintains PVC generally comes to 20 percent less than the rival materials "Actual installation savings were even greater." suggests Keith Wilkinson. Jr.. President of Aiden Excavating The 20-foot length of 30-inch PVC is handled with light-weight equipment. Inc.. Cowlesville. New York. Wilkinson's company put in every foot of the large diameter force main "at a conservative estimate of 25 percent in cost savings versus ductile iron." The company averaged 150 feet of pipe installed daily (in 8 hour days). "We initially figured on 75 feet per day due to the number of cuts we had and the numerous tight working areas. These numbers speak for them selves. They left us absolutely delighted in the job," Wilkinson says. That's not all. Wilkinson expressed appreciation for the PVC gasket system as well. "We had a lot of changes in direction, at least 20. and some were as much as 90. both vertically and horizontally. We went under railroad tracks and bridges, and even under the Tonawanda Creek. All of those bends and no leaks. Not one." Wilkinson is quick to point out how easy PVC pipe is to work with, even large diameter. "Lengths come together nicely, cutting is fast, the pipe is light and easy to handle and we were able to get away with using much lighter equipment and less labor. It was a pleasure." he says. "On top of all this." adds Dennis Larson, "there wasn't one delivery problem or delay. We evaluated the pipe carefully to start with, and now that the job is completed, we are confident we made the nght choice." The design flow rate is 10.608 USgpm and the friction loss rating ts only 0.200 ft/100 ft. Dual PVC Force Main Relieves Pembroke Pines, Florida According to Larson, the city "has no way to bypass the line. A breakdown would mean a complete shutdown ot the system. Consequently, the pipe must perform" Installation of the new Batavia lorce main started in mid-Ma). 1988. It was com pleted on schedule by September ! Now tested and ready lor use. the force main awaits com pletion ot the treatment plant sometime in 1990. Bryan Smith of the consulting engineering firm of Tallamy. Van Kuren. Gems and Associates. Orchard Park. New York, is equally optimistic about the successful, long-term operation of the system. As the resident engineer on the project. Smith anticipates. No prob* lems whatever." with the unique new force main. One reason it the track record of all of the PVC pipe previously insulted in the city. "We have used a lot at Um-Bell member company PVC pipe with no instances of pipe failure." he says. In the past year. Batavia installed close to 24.000 feet of PVC pipe for gravity sewers, including an additional 2.500 feet ol the same 30-m. PipeSmith makes his second point by referring to test results for the pressure force mam. "Although normal use pressures in the line will be 30-40 psi. we tested it at 100 psi and held that pressure for four successive days. There were no leaks." The new PVC force mam has a capacity of 22 million gals per day. The system is designed The City of Pembroke Pines, Florida, ha. been grow ing al a rapid pace the last tew years, and expectations are that it will continue growing rapidly into the future. When the City recently annexed a 20 square mile area, known as the Western Service Area (WSA). there were some utility concerns which required immediate attention. The most crucial concern involved an existing sewage treatment plant which was servicing a small community at the extreme west end ot the WSA. The plant was undersized to meet future demands and was producing etfluent which didn't meet current state standards. The city turned to Berry & Calvin Inc.. Consulting Civil Engineers, from nearby Holly wood; Florida, for assistance in determining the best alternative for meeting both the current and future sewage treatment needs. Edward J. Dvorak, a Project Manager with Berry ii Calvin, was selected to head up the design as he had completed Pembroke Pines' master plan for the WSA. One factor which compli cated the design j> the fact that the WSA was largely un developed. This meant a significant difference between current and future How demands, which were estimated at 310 gpm and 5210 cpm. respec tively. A computer generated model of the system resealed that a dual force mam iS' force main along side gradually increasing 10" to 24 torce main) was the most economical alternative. Mr. Dvorak stated that. "A twin force main offers the opportunity to phase the usage. A smaller diameter mam operating with a large diameter main allowed efficient pumping at the current relatively low flows as well as the ability to handle future increased flows Pipeline velocities are main tained within the smaller force main until increased flows require us to open up pontons of the larger main.* The force main would contractor was allowed to select either PVC. ductile iron or concrete cylinder pipe for the project. Pk C pressure pipe wj> provided by the contractor in the following diameters and quantities: 6'' 8'' 10" 12" 14" 16" 18" 20" 24' Total - 195' - 37 91?' - 7.678' - 1.587' - 10.534 - 5.253 - 8 561 - 8.322' - 2 115 - 82.162' deliver the sewage approxi mately eight miles to the Pembroke Pines treatment fa cility. The design analysis resealed that approximately 198 feet of head <86 psi) would be required to pump the sewage over this distance. Two pumps in series with a wet well arrange ment were designed to meet this requirement. W hen it cjme time to select the pipe matenal. "we wanted to get the most economical product which would provide long-term service." stated Mr. Dvorak. The All of the 6-12' was DR 18 (Pressure Class 150 psn and the 14 - 24" was DR 25 (Pressure rated 165 psi t. Ed Dvorak, the City of Pembroke Pines, as well a. many other cities in Broward County. Flonda. had specified 6 through 12" PVC pressure pipe meeting the requirements of AWWA C900. Pol v v inv I Chlonde (PVC) Pressure Pipe. 4 In. Through 12 In . for Skater, for a number of years before this project. However, they had not used large diameter 114 and above) before. After thoroughly reviewing the Um-Bell standard (UNl-B-U), "Recommended Standard Specification for Polyvinyl Chlonde (PVC) Water Transmission Pipe fSommal Diameters 14-36 Inchi.' as well as the material qualities. Mr Dvorak found that. The large diameter PVC had the same physical characteristics and fContinued on Pa ft / 2, CTL027260 UniBcll PVC Pip* News Pag* 4 15 Year Old PVC Sewer Pipe Passes Tests Of Time \ (Continuedfrom Page l) The pipe easily passed the 7 1/2 percent mandrel. Department was very interested. The line was retelevised in They believed the research order to see what difference, if would greatly benefit their any, the jet cleaning made on the information base as well as the line. There were some minor user community in generai. To noticeable changes. Of special them this was an opportunity. In advance note is the fact that after fact, the City of Dallas Water the pipe was removed, ihe Utilities Department would act as the contractors for the UniBell sponsored project. The Pre-Excavauon interior could be easily cleaned with water and a small amount of elbow grease. (Editor's Note: When you attend the American Water Works Association Com Before excavating the line and sending it to the laboratory for testing, we wanted to know vennon in L.A., stop by our booth and see an actual sample.) how well it was currently operating. City crews reported that there were no recorded instances of maintenance on this line in us 15 years of service. The following five steps summarize the pre-excavation protocol. The Excavation On a sunny and warm December morning (1988). UniBell staff met the Dallas excavaiion/repiacement crew on site. The street had been marked and the asphalt cut pnor to our This quiet neighborhood is the site of PVC research. bottom of the pipe and from the sides to the spnngline was classified as SC and described as tan and grayish brown clayey fine to coarse sand with some Depth of flow measurement TV the line Clean the line Pull a deflection mandrel through the line Re-TV the line arrival. Before removal of any overburden could proceed, we would place a device in the PVC sewer pipe to maintain in-situ deflection over a two foot length. This was accomplished by yours truly, who spent several un fine gravel. Because the invert was approximately eight feet deep and the water table was slightly above the crown of the pipe, some of the native clay materials washed into these samples during the excavation process. Obviously, their forgettable moments inverted m Dallas Water Utilities had the manhole. By maintaining the set up a mobile recording device deflection in this section, the to measure depths over a seven actual long-term structural day period. Depth of flow over properties of the material could the seven days ranged from a be calculated. low of approximately one inch to The asphalt was removed a high of three inches of depth. and a nuclear densometer. The Dallas utility crew, operated by a Dallas utility which televised the line, consultant, was calibrated and explained that they no longer used to measure soil density just televise their PVC sewer lines, below the surface and then again as a part of scheduled main three feet down. The densities tenance. because experience had ranged from 82 percent to 92 shown there was little to see. percent along the length of the After viewing the video of the trench. 245 foot long section of PVC Terra-Mar Consulting Engi- ptpelme. we see their point. The neera, a Dallas-based firm which interior did not look brand new. specializes in geo-technical but it looked awlully clean for evaluations, was retained to 15 years of service. classify and define the native The line was then cleaned trench soil as well as the with a water jetting device embedment material. The final before the deflection mandrel backfill material, which was was pulled. Both the City and placed from approximately four manufacturer's initial install** to six inches above the pipe to non reports indicated that* about one foot below the deflections ranged from two 10 pavement* was classified as CH five percent over the length of material, described as "Dark the line. They both had usc6 gray lo tan clay with calcareous defleciometers to measure over modules and limestone frag the entire length. We were ments." prepared to pull a 5 percent The initial backfill, which deflection mandrel (a go/no go was placed from the xpnngline testing device) through the line. of the pipe to four to six inches Unfortunately, the outlet struc above, was classified as SM and ture of the manhole invert was described as Tan silty fine sand built up with concrete to the with trace fine gravel." The Cit> point that we could not wedge crew knew we were getting close the five percent mandrel through to the top of the pipe when the into the pipe. No problem, we backhoe operator struck this have another manhole down sand. stream. Wrong. The inlet The City requirements structure there was also built up. called for a "Class B" embed The next move was to try a ment material when the pipe was 7 1/2 percent mandrel, which is originally installed, regardless the industry recommended of pipe material, and still do allowable deilection limn. With This would be described as a much effort and manipulation it material basically consisting of was wedged through the up sand and gravel. The material stream manhole outlet structure. which was removed from the requirements were sufficient to maintain deflections below 7 1/2 percent. The water table being jbove the pipe made for nast> working conditions which were aggra vated by rainy weather. This didn't deter the Dallas utility crew. They brought in pumps to lower the water level and uncovered the pipe. Once uncovered, they cut holes in the crown and let the pipe assist in draining. A total of approximate!) 40 feet of pipe were required to test in accordance with ASTM D 3034. The 10 inch PVC was removed in two sections, one 33 feet in length and the other 1 feet. A house lateral prevented us from removing one contiguous piece. As the photo on the front page shows, the pipe was covered with mud upon removal. Even so. mans of the crew members commenied (hat the pipe looked practicall) new The mud was washed olf. the interior was rinsed and the pipe wj\ <.ui in lengths convenient tor shipment. rhe Testing The pipe wjs >eni m l uh State Universit) \ 11 SI > me chanical engineering department in Logan. Ltjh LSI in reco gnized as a premiere pipe research facility. which made ihe choice of laboratories an easv one. Apparently we didnt Jean the interior of the pipe j' thoroughly as we could hj\e The folks jt LSI reported an overly offensive odor upon uncrating the sjmplo Wc II blame the user of this pipe he s obviousl) runmne smells 'tuff Utah State University receives the PVC sewer pipe. through it. USU tested in accordance wuh ASTM D 3034. which has requirements for workmanship, diameter dimension, w'all thick ness dimension, flattening, impact resistance, pipe stiffness, joint tightness, and extrusion quality Workmanship The require ment states (hut the pipe and lutings Nhall he homogeneous throughout and free from visible cracks, holes, torcign inclusions or other injurious defects. The pipe shall be as uniform js commercially practical in color, opacity. density and other physical properties. After 15 scars the PVC pipe passed the requirements. In fact, the report from USU states that, after cleaning with soapy water the appearance was almost like new pipe.'* Looking like new is one thing, hut what about phvsical properties.* Diameter dimension' The jverage outside diameter when measured in accordance with ASTM D 2122. Standard Method of Determining Dimensions ot Thermoplastic Pipe and Fimngs.' was I iund to he two ihousjndths of an inch under the tolerance. This minor variation in dumeter obviously hod no affect on performance Wuh today's computer controlled extrusion equipment, the tolerances can be more easily met today. Wall Dimension Simply put. the wall thickness exceeded the requirements when measured in accordance with ASTM D 2122. The samples had averjge wall thickness ranging from 0.307 inches to 0 314 inches. Alter 15 sears ol service, ihe wall thickness, even in (he invert, was greater than that required by the standard tor ness pipe. Granted domestic sewage is not normally very abrasive, but we all know that things go into the system which shouldn't Previous studies have confirmed PVC's high resistance to abrasion. Pipe Flattening The ASTM requirement states that (here shall be no evidence ol splitting, cracking or breaking when flattened to 40 percent ot the outside diameter. Bv flattening to 40 percent of O D . the pipe is deflected 60 percent. The accompanying photo is worth a thousand words. The I* year old PVC pipe passed the test. There was no embrittlement wuh time. hnpuit Hesistam v \STM D 3034 requires that 10 inch diameter pipe withstand 220 it* Ibf when tested in accordance with ASTM D 2444. SljndafJ Test Method lor Impa*: <C nntmuvd on Pa:c ' 1 15 Year Old PVC Pipe Passes Tests Of Time (Continued on Page 4) Resistance of Thermoplastic Pipe and Fittings by Means of Tup (Falling Weight)" This standard requires (hut pipe specimens be able to withstand a blow from a missile-shaped falling weight called a tup. The tup is 20-lbs., therefore, an 11 foot drop. This test was meant as a quality control requirement rather than a requirement for field installation. All samples passed, providing further evidence that no embrittlement occurs over time with PVC pipe. Pipe Stiffness. A minimum of 46 psi is ASTM's requirement for SDR 35. All samples were tested in accordance with ASTM D 2412. ''Test Method for Determination of External Loading Characteristics of Plastic Pipe by Parallel Plate Loading." The average pipe stiffness was 62.8 psi. Joint Tightness: Within D 3034 is a requirement that the elastomeric gasket joints per form in accordance with ASTM D 3212. "Standard Specification for Drain and Sewer Plastic Pipe Using Flexible Elastomeric Seals." This standard requires that the pipe undergo both an internal pressure and vacuum requirement when axially de flected. The sample passed the test. Fifteen years later the PVC gasketed joint was leak free. Properly installed PVC sewer pipes comply with a recom mended allowable infilmmon of 50 gallons per inch ol internal diameter per mile per day. Most alternate sewer pipe products cannot meet such low allowable infiltration levels when newly installed, let alone 15 years alter installation. Extrusion Qnahtv ASTM D 3034 requires that the pipe not flake or disintegrate when tested in accordance with ASTM D 2152. "Standard Test Method for Degree of Fusion of Extruded Poly(Vmyl Chloride) (PVC) Pipe and Molded Fittings by Acetone Immersion." Samples were submerged in anhydrous acetone for the required time and in spected. All successfully passed. Stnutmal Propet tics: Within a limited group of users and non-users of PVC there lingers a question concerning long-term structural properties. They would suggest (hat properties such as tensile strength and modulus of elasticity decrease with time. We thought you would be interested in seeing what the testing revealed. When the 15year-old PVC pipe was tested in both the circumferential and longitudinal direction for tensile strength and modulus of elasticity, the adjacent results were obtained. As you can see. these values are typical of newly manu factured pipe. The Additional Testing Remember that we said prior to removing any overburden from the pipe we installed a device which would lock in the long-term deflection. Well, we did this for selfish reasons. By providing USU with this sample. UniBell PVC Pipe News Pape 5 The 15-year-old PVC passes the flattening requirement. CIRCUMFERENTIAL DIRECTION Specimen Number 1 2 3 4 Strength (psi) 7410 7600 7700 7670 Modulus (psi) 0.376 x 106 0.441 x 106 0.403 x 106 0-430 HO6 AVG. 7600 0.412 x I06 LONGITUDINAL DIRECTION Specimen Number Strength (psi) Modulus (psi) 1 7990 0.449 x 106 2 7980 0.437 x 106 3 8140 0.432 x 106 4 8060 0-458 x 106 AVG. 8040 0.444 x I06 PVC Pipe Time Capsule Preserves City Keepsakes frv Robert Walker To wrap up Texas' 150ih birthday celebration, the City of Richardson. Texas, buried a limn capsule to preserve this imml period for the future. Th* capsule, which will not b* opened until 2036. during Texas' 200th birthday, contains memorabilia from the sesquicentennial year, photos, messages, business cards and a letter from the Mayor. To protect these historical documents and artifacts for future generations, the city selected a construction material dM would not detenorate under conditions of burial. The time capsule was made from PVC pipe and was donated to the city by the Richardson Water Department. When it has to last, specify PVC pipe. they were able to measure deflections, measure the toad required to maintain the deflection and incrementally load the sample to reach ihe required deflection for determination of pipe stiffness. The pipe stiffness ealeulated. at the required deflection. was 65.1 psi. With this value, the modulus of elasticity could be calculated. It had not decreased from those values determined for unrestrained samples. P\C The Richt Sniff We said early on that this article would serve as a report card on how good your decision to use PVC sewer pipe has been. We would say you get an A+ and go to the head of the class. Your decision has been rewarded with not only superior performance but supenor durabilitv as well. The ASTM D 3034 yardslick limited us to 15 years. Nevertheless, ihe results gne us no reason to suspect any different results would be densed from 150 year old PVC sewer pipe. Based on the fact that the 15 year old PVC passed all the requirements of newl> produced pipe, with the \ineular exception of average O D our opinion is (hat your great, great grandchildren's children will still be serviced by the PV C pipe vou specified. We will not be around to see the final report card. When you evaluate PV C on durability and periorm.int.tf h dictates your selection Edittir't Sole 4 i "P' the original icpoH {mm l 'jh State L'nnei sn\ it juu uh.'i from L ni-Bell hcadquai '< - > " Dallas Texas Correction: AASHTO Design Specification Example CTL027262 In our Summer 1988 edition we reported on the approval of an American Association of State Highway and Transportation Officials (AASHTO) design specification for PVC highway drainage culverts. As part of that article a design example was included. The design example in cluded both service load design critenon and load factor design criterion The service load computations were correct but the load factor burial depth limit computation did not take into account y and 0g factors from AASHTO Design Section 3. The specified load factor design yand 0g values for flexible culverts are 1.3 and 1.5. respectively. These factors multiplied together effectively increase the design load 1.95 times. The result is an allowable burial depth of 18 3 feet when load factor criterion are applied in the example. Although less conservative, our use of the actual dead load does yield a very sale and conservative buna) limit tor PS C culverts. In a related matter the PASHTO Special Liaison Committee for Flexible Culverts has identified an error m the capacity modification factor ioi used in the load factor design method for PVC culverts The AASHTO Plastic Pipe Task Force inadvertently set the O factor equal to 0.65. The o factor should be I 0 to be consistent with other AASHTO culvert design sections and to restore consistency between the service load and load factor design methods. VS hen the O factor is corrected, the allowable burial limit from our previous example computations will be 21 feet using the load tacinr Jr..n method. We hope we have . s cJ ihe proper uppli.u' AASHTOx design . obtain a copy ot v v - -t ' ' Design Section I x eniin-.j s Thermoplastic Pipe I'- c-j. i Systems,' you nj' j- AASHTO General hr ..- --- North Capitol Street N . . : 225. Washington DC 2"' UniBell PVC Pip* News Pge 4 Uni-Bell Welcomes New Members The Uni-Bell PVC Pipe Association is a non-profit technical and educational organization headquartered in Dallas. Texas, which provides information regarding the specification and use of gasketed PVC pipe products, for use in water, sewer, drainage jnd irrigation applications. The Association is made up of manufacturers commuted to providing quality products and service to the PVC pipe industry Formed in 1971. Uni- MltO Bell offers technical service, research and development data and support in standards development. Uni-Bell is proud to be directly affiliated with quality producers of gasketed PVC pipe. BFGoodrich B.F Goodrich Canada Inc. is Canada's largest domestic producer of vinyl resins and compounds. The company's plants are located across Canada in Shawinigan. Quebec; Niagara Falls. Ontario; and Scotford. Alberta. BFG Canada is a subsidiary of the BFGoodrich Company headquartered in Akron, Ohio. Strong demand for PVC products in Canada has resulted in the growth of an established customer base for B.F. Goodrich resins and compounds. To meet demand, the company is expand ing its manufacturing capacity. Customers of BFG Cana have "state-of-the-art" know-1- edge of PVC processing, with an emphasis on technology and high quality goods. B F. Goodrich has met the challenge of keeping pace with us customers' demands for quality and innovation through the introduction of comprehensive Statistical Quality Control (SCQ) and Statistical Process Control (SPC) in us plants. Improvements to existing proven resins and the introduction of new resins offering improved processing and physical properties are ongoing. The company has the advantage of being able to supply suspension resins from its Niagara and Shawinigan plants. Its Scotford. Alberta, facility is one of the largest and most modem mass resin plants. The flexibility of having both major types of PVC resins provides customers with access to the best resin for A mW m Vinyl m m Institute A Division of Tho Society ot Tho Plssttcs Industry Inc. The Vinyl Institute is a affiliated members. Current trade association representing affiliate members are GE (he leading U.S. manufacturers Specialty Chemicals. Kaneka of polyvinyl chloride (PVC) and Texas Corporation. Lucidol vinyl chloride monomer (VCML Division of Pennwait Corpo the raw material from which ration. MAT Chemicals Inc.. PVC is derived. Memb- Rohm and Haas Co. and Witco companies include Air Product* Corporation. and Chemicals. Inc.. Bordeir Founded in November 1982 Chemicals and Plastics. as an operating division of the CertainTeed Corporation. Dow Society of the Plastics Industry. Chemical Co.. Georgia Gulf Inc., the Vinyl Institute's First Corporation. BFGoodrich Co.. major objective was to correct Occidental Chemical Corpora misconceptions and erroneous tion. PPG Industries. Inc.. allegations by marketplace Shintech Inc. and Vista competitors about the perfor Chemical Co. European and mance of PVC pipe and conduit Canadian PVC interests are in fires. During its first iwo represented as well by associate years, the Institute launched a memberships held by the Vinyl massive coordinated campaign Council of Canada and involving revearch. development European Vinyls Corporation. of educational programs for In 1987. a new class of firefighters, communications membership was established to and public relations that has enable I'.S. companies that successfully helped to confirm manufacture adjutants or other the safety of vinyl products. raw materials that are used in Today, this responsiveness the manufacture, compounding continues in VI activities. As the or fabrication of PVC to partici voice of ihe PVC industry, the pate in Institute programs as Institute aggressively and PVC fittings. PVC resin jnd PVC compound micro ingredi ents The following companitfN have distinguished themselves as responsible new Associate member companies. Uni-Bell member companies benefit from j philosophy that lop quality pipe, service and technology all go hand in hand. The following Uni-Bell member companies serve the PVC pipe industry and their customers with quality products, professional personnel and Uni-Bell technical expertise. their application and process. Canada has been favored with abundant supplies of natural resources. Large gas fields and salt deposits provide reliable supplies of the basic raw materials for PVC (ethylene and chlorine). On Canadian minds in 1989 and beyond will be the ramifications of the Free Trade Agreement. By and large, the PVC industry looks forward to the exciting opportunities presented in a North American marketplace. Organizations such as UrnBell, which have been operating in Canada and the U S for some ume. have actively demonstrated (hat both countries share similarities which transcend the border. B.FGoodnch Canada Inc. is pleased to be joining Uni-Bell at this time and looks forward to meaningful participation. responsibl) promotes the con tinued development of the v in> I industry by: Educating the public about the sdfets and performance of vinyl. Sponsoring health jnd environmental research to assure the safe use of vinyl products. Development of marV.ei-piace opportunities for expanded uses of vin> I. Fostering programs jnd communications with other industry groups (Domestic and international trade associations >. For the past two years, the Vinyl Institute has helped support a cooperative program with Lm-Bell PVC Pipe Association to expand the u->c of large diameter pipe More recently, the VI has embarked on a pro-active program to help in creating expanded market for PVC in packaging. elcuriLjl materials and piping applica tions. An integral pan ot th\ programs is the development of informational brochures tech nical information paper- jnd j generic jd\erti>tng campaign aimed at reaching influential purchasing decision mjkers Headquartered in NNjyne New Jersey the Vinyl Institute in governed by jn executee board representing all member companies and in managed by an executive director CIlCorma Inc10 MclEARY COURT CONCORO (TORONTOl ONTARIO CANADA L4K 222 TELEPHONE <4 I6i6$9-9J9T TELEX 06-964 580 Cornu Inc. was established in 1971 jo develop, manufacture and market plastic corrugated pipe productions systems, which were available only in Europe at that time. Taking this opportunity, we wish to introduce you to Corma. the largest supplier of corrugated production systems in the world, with its head ottice and manufacturing facilities located in Canada. In ns Research and Development Department. Corma is continuing tech nological innovation, citing (hat its commercial growth is directly related to its R. & D. Corma designs and builds complete corrucator systems tor the production of corrugated plastic tubing and pipe for automotive wire harness con duit. electrical conduit, medical respirator tubing, swimming pool hoses, underground cable ducting, drainage, irrigation piping, sewer and culverts. These end pipe products are manufactured on Corma equip ment in either blow or vacuum forming, with a pipe size range from 3 mm I.D. to 1200 mm OD. The lour comigated s> stems allow the pipe processor to manufacture u Miigle-wall. double-wall or spirjl wound pipe. In addition, the newest sanitary sewer pipe system, the Ultra-Rib System. This recent advancement in pipe design is ideally suited for PVC as there is no fusion of pipe layers required. The Ultra-Rib pipe is a smooth pipe with rjdial reinforcing nbs and is produced from only a single layer of plastic. The unique profile of Ultra-Rib pipe gives it j very high crush and impact strength, still the pipe remains very light and requires about half the material to produce than other comparable pipes. Corrugated Plastic pipe can be made from almost all blow and vacuum forming plastics, such as PE. PP. PVC thermo plastic rubber, nylon, leflon. etc. Corma also butlQs. as pan of the system, dies and downstream equipment includ ing such items as watertank aftercoolers, haul-off and pipe dry-off stations, rourv cutters and slitters tor drainage pipes. An ever expanding com pany. Corma offers its customers the best and latest ot knowledge m corrugated pipe production PVC Pipe News Published By Uni-Bell PVC Pipe Association 2655 Villa Cree* Dove Suite 155 Danas Texas 75234 Teieohone t2H> 2*3-3902 Fa* <214,243-3907 hu-vuuu Direitt* ft*vn t> Wjikcr Ph (`hjimidn \iw ( hjimijo OFFICFRS J.rr Rj.h lt.nt Tnr..\ct n`Ur\ 1 n:j'urrr 1-fTltV Pf"0*kc RLGILVK MLMBf.RS ( annul life f.struvrun TVehns-li'yiC' lnv C jfl<<n 1 XI Mdnuidv.iurinv ( " In. l "citv.n ( Hmdikl' lrv PjmIk Wc-iwm f-xintskd Plj-itv. ( 11 trtwvnj 1*1aviiv' (.`rptr.iiHUi X*wp?i.`r Xl.inul.Kiunni: ( <> t .J X-pn^jn IM>RN VTIOV VI XFHl I VTt: MhMHFRS ( .n'wrv | (.n I imitcJ Hj-Jt. IpH \ Huitk Hiv... Tufais HcmpIv' X V tfc ( \ l fN-ry..' \jvv,.i. In. V nuk' TuKm*hy.f* Mn I tmti.a \SVJCI\TF UrvtBHfS rt I (...Nifi.n CutiuJu Ifk Mjrri,). ~ K.r (.`mv, Irk Muln htimv* C<>rp h-fstHUj I'tfkr Xcdl C <unfvm\ Vmmn Xrvjrv Munuluiiurift. ( CTL027263\FFIU\TH) \SVX*l\TIO\ Tht. V<r\. ln%itiuie Thi 'UKmem- i* ihi- pwNkuIkw jfv mi*. ! me l nt bi.il MX ( Pipe Aw*..utH>n u.-.J wfv tvu wjrrjnnc' n* arv the> imeixted i* N. vjfnmito Injurne* fr ininfmjii"p -r -,-Xv `u pr<AJw.i' ,fk-ir jimhulc' utui remended uv,' 4fkt minuldtturv- - * rvHjt J fk jin.c icd mefnt^r itimpdrtie' \lifvvc6 i v cn 4Mciflp8 t m^dt. in d'Mjfc lu.tgui auia' Cm Bell ufk. Mv.\dikief Vst* dtvcp nn re>pn*ivtNlir> lor anintemtiuidi erts-fv tuhvr .mxitnn m 4 future i.uc p-m - .a Dallas Installs First 18-Inch PVC Circumferentially-Ribbed Sewer Pipe UniBell PVC Pipe News Page 7 While small diameter circumferentially ribbed PVC sewer pipe has been installed throughout (he United Stales. oni> recently has it been manufactured in IX inch diameter Eight through lilteen inch has been produced tor some time by this innovative tech nology. which oilers pipe having a seamless unitorm crosssectional waJI. radial ribs (circumferential], which arc perpendicular to the jxis ot the pipe, a smooth interior for excel lent flow characteristics and an integral hell and gasket joint. During the spring ot 19X8. Haukos Construction Company ol Dallas. Texas, installed 5.320 feet of the Uni-Bell member company 18 inch PVC sewer pipe on the Ash Creek relief interceptor project for the City of Dallas. Much of the trench was cut through solid rock. Haukos Construction was able to move quickly by using their trenching machine. It is fitted with an 18 toot boom and was able to cut a 30 inch wide trench. This along w ith the light weight of the PVC pipe insured a timely completion. Mr. Don Haukos. President and owner ot Haukos Con struction Company was pleased with the pipe's lightweight (134 pounds per 13 foot length). Mr. Haukos said. "This jllowed economical hand installation, saving on the cost ot equipment needed to handle heavier pipe." He also sjid he liked the radial rib construction which gave the pipe extra stillness and allowed it to be cut anywhere. 'This rib construction allows me to cut the pipe to the length I need. reposition the gasket jnd push the pipe togciher--m> need to bevel cuts anymore This is a real lime saver." Part ol the job required pushing 53 teet ol the IX inch PVC pipe through a solid rock bore under Peavy RoadAccording to Mr. Haukos. "We pu^ied the pipe through the bore with ease Then we pressure grouted the opening between the O.D. ot the pipe and the bore hole. It worked slick as a whistle." There were II manhole sections on the project. Each manhole employed an "A-Lok" connection for water tightness. This connection was last and simple to make using the smooth manhole adaptor furnished by the manufacturer. The radially ribbed PVC pipe was installed m accordance with the standard City ot Dallas installation spec it icjturns The bedding and haunchmg material was 3/4 inch crushed stone, which was placed 4 inches under the pipe to 2 1/4 inches above the springiine. Sand was used as initial backfill and placed 12 inches over the pipe Native material was then placed in the ditch to original ground level. After installation was complete, all sections success fully passed both an air test and deflection test. Mr. Haukos stated. "Since the Ime was in a street which required repaving, the City of Dallas televised the entire line with no problems." The ribbed sewer pipe awaits installation. The trenching machine speeds up construction. THE HOW-TO HANDBOOK OF PVC PIPE 250 PHOTOS. FIGURES. EQUATIONS. GRAPHS The only complete reference for thaw who plan, design, ireuail and operate PVC sv stems lor mum*. >P4i w jicr mams. pouhk water distribution and sanitary sewer system*. It you are planning, or now opemt PVC pressure or non-pressure system, this Handbook t> j ML sT' PRICE $40 (Payable in U.S. Funds) Texas Residents Add 8 Percent Sale. Tax Plus air mail charges: Canada...................................................................... S.slhook Europe. South America............................................S22/bool. Central Amencj. Cjrihhean...............................S11 Sool. Asia. Alnca. South Pacific ............................... S25/book Mail Coupon With Your Pa>mem To: Ini-Bell PYC Pipe Association. 2655 Villa Creek Drixe. Suite 155. Dallas. TX 75234 NAMECOMPANY ADDRESS______________________________________________________ __________ __ CITYSTATEZIP CODE COME SEE US At A.W.W.A! Booths 838 & 840 The Amcncan Water Works \nsoc iation i AW W A i annual xonlcrcnce and exposition this xcar xx ill he held in Lox Angeles California. June IK-22 Im-Bell and 11 member companies xxill he there in a big xx ax io celehraie the conference premiere of C'ldS. POLY\ |N> I CHI OR IDF iP\ f. WATER TRANSMISSION PIPE. NOMINAL DIAME TERS 14 IN THROUGH -h IN " The nexxexi technologx m non-pressure PVC piping xnii also he on displax So come see ihe blest and allow us io renexx our gm.J friendships ai the exposition m N.iih. s-.x a. san UniBell PVC Pip* News Peg* * The Effects Of Deflection On Sewer Hydraulics bv Robert Walker. PE Where: a * hull the length Simplification ol this requires calculation using the Where S = the elliptical ot the long expression can be accomplished "elUpue.il integral." As with jin radius" Nearly every hydraulic?! (horizontal) avis by introducing the numerical pijH.*. determination ot the How The equation lor the radius handbook and wastewater b = hall the length eccentricity: u.ipaut) requires calculation ol squared at angle 0 lor an ellipse engineering textbook include of the short the Imiraulic radius and the area is: sections dealing with circular pipes. Many empirical equations have been developed to provide solutions to circular pipe flow problems. Blasius. Chezy. (vertical) axis. An ellipse will also satisfy the following equation. e* a It is possible to subsiitute \ * sin 0 and use the boundaries i ot the wetted cross section flow Figure J depicts the cross section ol a partially full del Ice ted pipe. The wetted perimeter part ACB ot the S2 1 - e2 cos2 9 Colebrook. Darcy. Fanning. = - rt/2 and j = rt/2 (half ellipse) elliptical perimeter ejn be Huzen-Williams, Kutier. Man sielding the following equation calculated b> detining the ning, Moody. Morris. Scobey, tor the elliptical circumference boundaries js The arej ot the elliptical Streeter. Strieker and Weisback ElhpiK ul Cm ttmfcrcm e <Cc): segment can now be written as: are some of the more prominent names associated with circular pipe hydraulic evaluations. Thus, the design engineer has easy access to methods For a deflected pipe, the values of a and b must be fixed so that the circumference of the ellipse (deflected pipe) and the 1/2* Ce = 2a JVl - c2 sin2 9 d0 \IZk = - rt/2 A0Bellipse - Then the wetted perimeter is calculated: f------- j----------dQ j' * ' e~ cos appropriate for dealing with original circle (undeflected pipe) circular pipe hydraulics, i.e.. are equal. A circle's circum The above integral is known flow capacity, headloss. flow velocity, etc. Buried flexible pipes, how- ference (Cc) is simply: Cc = 2rtR Jvas the "elliptical integral'' and cannot be solved with CWp * 2a 1 - c- sin- 8 dO The wetted area can be elementary functions. Numerical -n/2 calculated b> simply subtracting evei. are engineered to deflect. A solution requires using a the triangular area ABO Irom flexible pipe's ability to deflect computer to handle the large the area ot the elliptical offers two major structural The determination of an number of calculations needed. segment. The area ol the triangle benefits; 1) significant stress elliptical circumference is not so is: reduction brought about by im simple. The length of an Elliptical Deflection Where Cwp = the wetted proved load distribution around elliptical curve can be calculated the pipe's circumference and 2) using the following integral: perimeter of an ellipse. For a deflected pipe, the ABO,njn8|e = (S sm kS cos ) superior resistance to cracking or ongtnal pipe circumference (Cc) The area of the elliptical (Please turn to Po^e 9 breaking that tn turn prevents costly leakage. Such deflections J L(ij) JVl + yl2 dx will always equal the elliptical segment AOB can be calculated circumference (Ce). as follows: also result in some deviation from a pipe's original circular cross-section. If the deflection is t Where: Ld.j) = elliptical arc Cc = Ce J AOBeiiiple m Js2 d0 large, the change in cross section length be Using this constraint, the may alter the hydraulic characteristics of a pipe enough tween bound values of a and b for a deflected aries i and j pipe can be calculated. The Table 1 to warrant evaluation. In this article the influence yi s> derivative of values of a and b that the function correspond to various deflec Values of a and b, when R * 1 that pipe deflection will have upon the discharge capacity of an initially circular pipe is For an ellipse: y = f(x) tions are provided in Table I for Pipe R = 1. Deflection a/b 3 b evaluated. Both full flow and partially full situations are considered. bx yl"V?ZTir Figure 2 diagrams the above deflections so that you can get a better physical idea of w hat these deflections imply. 0% 2.5ft 1.00 1.05 1.00 1.024 1 00 0 975 Elliptical Cross Section Therefore, the arc length for Elliptical Pipe Hydraulics 5ft 1.10 1.047 0 952 The amount of deflection an ellipse becomes: and the profile of a pipe's To calculate the discharge 10ft 1.20 1 089 0 907 deflected cross section will depend upon the pipe s embed ment. loading and stiffness. The j,: ellipse most closely models the M cross section profile observed in b2) xV capacity of a complete!) i partiall> filled elliptical pipe dx 20ft 30* 1.50 1.80 1.188 1.260 0 792 0 700 buried PVC pipelines. A practical analysis requires that it be assumed the pipe will deflm. to form a pure ellipse. Figure 1 shows the cm* section geometry of a circle aat an ellipse. Using polar coor* dinates the following equations define a circle. x = R cos 8 y = R cos 8 6Where: R radius of a circle angle of the radius with the x axis The following equation also applies: rr x*> + y-> = _Ri- Using the same notation, the following equations define an ellipse: x = a cos 0 y = b cos 0 9 *vj ^_________2 Figure 1 Elliptical w Circular Geodmtry Figure 2 Elliptical Segment* That Correspond With Specific Pipe Deflections CTL027265 UniBcll PVC Pipe News Page * The Effects Of Deflection On Sewer Hydraulics (Continuedfrom Pa$e fi) A single equation for (he wetted area cun now be written js follows: T af j- . Jl-eW 1 -e2cos2 511 -it/2 Using this equation tor the welted area (A) and the previously derived equation for the elliptical wetted perimeter (Cwp). the hydraulic radius can be calculated. Where r = the hydraulic radius of the wetted cross section of the deflected pipe. Simple trigonometry pro vides that the water depth (H) is determinant by the following relationship: H = b - b sin Application of these equa tions. together with those front common hydraulic textbooks, enable us to compute the discharge capacity of either completely or partially filled deflected pipelines. Calculation Results A computer can be used to calculate the discharge capa cities for various pipe deflec tions and flow depths. Figure 4 graphically summarizes the results. As expected, discharge capacity is greatest with an undeflected pipe. However, the influence of the deflection on hydraulic discharge capacity is not significant until deflection exceeds 10 percent, i.e.. less than 2 percent discharge capa city reduction for pipe deflected 10 percent. To more clearly depict the percentage discharge capacity reductions. Figure S was developed. The graph shows that for deflections larger than 10 percent, the reduction in dis charge capacity may be signif icant. The degree of significance will depend upon the amount of deflection and how closely the selected pipe size came to meeting the maximum discharge requirements for the pipeline. These calculations and the resultant graphs can be used to determine the hydradTic signifi cance of anticipated or actual pipe deflections. Normally, the very minor or insignificant hydraulic influences of PVC pipe deflection are more than offset by PVC's smoother in terior waterway and fewer joints. Longer pipe lengths and smooth walls combine to afford lower hydraulic friction which yields higher flow velocity and increased discharge capacity. D u a ritr Rums Vaitr Figure 4: Discharge Capacities for Various Pipe Deflections and Flou Depths CTL027266 Pips DtflecSnn in 14 Figure S: Percentage Discharge Capacity Reduction for Deflected Pipes Floetng Full UniBea PVC Pipe New* Page It PVC Force Main Design Is Key To Long-Term Performance FIGURE A By Dennis E. Bauer 231 of 2nd edition. Stef) 3 Determine the Association Engineer At 1400 gpm. the velocity is wimjc l>i'e.s\uic.s (Ps) associated as given below: with the masimiwi (hange in PVC has fast become the \el<H itv (JIM. In this example, it designer's choice for sewage Velocity is assumed that no surge control force mains. PVC has gained a reputation as a superior EE fps devices are incorporated into the design. Theretore. the maximum performer for this application. 14 4 559 change in velocity (AV) is taken Excellent flow characteristics, 18 4.217 to be the maximum velocity. Hazen & Williams C = 150. a 25 3.919 Surge control devices should be non-corrosive nature and system economy are just a few of the reasons PVC has received such high regard. As with all engineered facilities, sound design is the key to economic long-term performance of PVC force mains. Particular attention must be given to the key design variables. We quite regularly receive questions concerning proper design of PVC force mains. We appreciate the interest and hope the following design example provides answers to some of your questions. SYSTEM DESIGN CONDITIONS Step 2 Determine pressure required to pump to the manhole (Ppl. From Figure A we deter mine ihc elevation difference is 45 feel. Therefore, pressure required to overcome the ele vation difference (Pe) = 45 ft x 0.433 psi/ft. Pe = 19.5 psi. Pressure to overcome friction losses in the line (Pf) may be determined by multi plying the pressure drop values given in Table 41 of the aforementioned Handbook by the length of the line as follows: Pressure Drop OR osi/100 ft Length of Main Pf f. 100 ft) (PSI) Given: 7,500 feel of 12" 14 0.224 cast iron O.D. PVC pressure 18 0.185 75 16.8 75 13.9 provided. Water hammer or surge can cause serious damage to the system if not adequately considered. Additional savings m pipe material costs may be obtained by including surge control devices such as slow closing valves, pump flywheels, surge relief tanks and pressure relief valves. Air and vacuum relief valves should also be included in the system. These devices reduce surge pressures by reducing the change in velocity (AV). Surge pressures are calculated by multiplying the wave velocity (a) by the maximum change in velocity and dividing by gravity (g) as shown in the following equation: P = aV/2.31 g. For more information see pages 115 through 119 of the Handbook. The maximum surge Pressure Class QK (PMl PP Ps PI (PM) (pM) 14 200 36.3 90.3 126.6 18 150 314 73.4 106.8 25 100 31.1 57 6 88.8 These total pressures represent those which would be experienced very near the pump station. Pressure to pump (Pp) would be reduced incrementally along the line. In this panicular example, there is a uniform decrease in working pressure from (Pp) to zero gauge at the manhole, due to the constant slope of the line. The surge pressure (Ps) is much less predictable in regard to precisely where along the line it will decrease. Air or other compressible gasses can aggra Consequently, design treatment lo accommodate cyclic surging and "cyclic fatigue" is being refined. Step 5: Ciici k for adequacy in fatigue Empirical equations devel oped by H. W. Vinson can be used in the conservative estimation of cyclic surge limns for typical PVC pressure piping systems. If the approximate number of cycles (C) which will be sustained in the life of ihe system is known, (he required design peak hoop stress (S') can be calculated using the following equation: ^5.05 x 1021~jn 204 pipe meeting the requirements 25 0.155 75 11.6 associated with an instantaneous vate the surge. This is why u is of AWWA C900, "AWWA Standard for Polyvinyl Chloride (PVC) Pressure Pipe. 4 In. Through 12 In., for Water," is to be used for a sewage force main. Fitting and valve losses have not been calculated for this example. They may be con verted to equivalent pipe length change in velocity of I fps. for the various DR's, is listed in both the Handbook and AWWA C900 and may be used to determine the maximum surge as follows: important to design ihe system to relieve surge. We see that (Pj) is well below ihe pressure class of each of the respective DR's. We also S' = Ca Required design peak hoop stress, psi Anticipated number of cycles in life of system. Sewage at a maximum future rate of 1400 g.p.m. will be transmitted through the line and represent a relatively small portion of the 7500' main. (See Figure 37. page 225 of the Ps* (AV * I 0 fps) .sv realize that in accordance with We are given that there are AWWA C900 DR's 14. 18 and 5 on/off cycles per hour. This Ps** 25 have a built-in allowance for equals 10 surges per hour. If we approximately 1.42 miles to a manhole as shown in Figure A. The main has been designed such that the pumps will start and stop five times per hour. The mam will be constructed in the aforementioned Handbook for equivalent lengths.) Pressure required to pump the sewage to the manhole (Pp) equals Pe + Pf. DR 14 18 25 (psi) 198 174 14.7 (fpx) (psi) surge based on an instantaneous select a 50 year design life, ihe change of velocity of 2.0 fps. anticipated number of cycles 4.559 90.3 This adds an additional 39. 35 may be determined. 4217 73 4 and 29 psi. respectively, C' = 10/hr x 24 hrs/day x 3 919 37 6 pressure capability to each. Now 365 days/yr x 50 sears = we have a basis io begin a check 4.380.000 cycles southern midwest U.S. with an average frost depth of 2.0 feet ft will be placed below urban streets for a majority of its length. Q 14 18 re (osl) 19.5 19.5 rr (osil IPrSPII 16.8 36.3 13.9 33.4 *See Section A.3.3 of AWWA C900 Surge pressure obtained by multiplying Ps @ AV = 1.0 fps times the maximum AV. for adequacy in fatigue. Fatigue phenomena are well known and commonly con sidered in the design of piping systems regardless of ihe piping s.,flo?UP-2ho.1.204 1^4.38 x 10 J Purpose of Design: To 25 19.5 11.6 31.1 Obviously, the surge pres* material. Only in liquid trans determine the appropriate dimen sures may represent the largest port systems where severe cyclic S' 1.182.0 psi sion ratio (DR) requirements of Obviously, the total pres portion of internal pressure the surging is anticipated is fatigue the PVC pipe to be used. sures along the line are well line will experience if they are failure considered to be a Having determined the below the pressure capability of not designed out of the system. potential performance limit. required design peak hoop INTERNAL PRESSURE D* 73 (PC 100). Bui because Step 4: Determine the peak Various empirical design stress, we may now calculate the CONSIDERATIONS velocities are higher than the 2.0 internal pressure (Pfi the line methods can ihen be used to required dimension ratio (DRi. fp which it accounted for in may experiem e. accommodate cyclic surging. As which equals outside diameter The key design variable fop. AWWA C900 and there are PVC pipe used in pressure itverai surge cycles per hour, we p,-pP+ps research on the subject contin* (O.D.) divided by minimum ues. understanding of the fatigue applications is generally interne! must check surge pressures. failure phenomena is expanding. IContinued on Pane III pressure. While force mains generally have very low internal pressures, they cycle on and off TABU 1 - calculated deflections OF BURIED AWWA CM* PVC PIPE DNImUm (FomU far Highway KM aa* Btflway El* Lm* several times per hour. This creates surge conditions. These conditions are aggravated by air and hydrogen sulfide gas which may build up between the intermittent flow conditions. Therefore, fatigue may often be the critical design variable for 'jrce main design. Step I: Determine velocity for maximum flow. See Table 41 (Flow Friction Loss, AWWA C900) of the UniBell Handbook of PVC Pipe: Design and Construction, page UM< i t1 r " 1i 4* 1I t: 1 1* --| ir!--1 12 1 1 U'--1____Ml ____ n 1 Lta Lmd -a i:(M(ni:nnnrwfni:iMii:iC(iii:HM(in;ictiii:(M<aji [nl E* Vataa 1 ______________DRUPrw--CtoM> 200 400 TOO 1000 04 04 0.44 040 LI 0.4) 1.9) 0.42 1.72 0J7 1-34 044 1.63 au 1.49 0.44 14) 049 1.19 0A3 1-33 0.33 1.42 040 146 0.43 1.13 040 1.34 0.62 142 047 1.09 041 0.91 0.44 1.19 0.7S 1.09 OJO 0.97 041 0.17 1035 1.14 0.94 147 046 0.9S 0.76 013 049 E Vifcw -- DR 11 PNun Om$ 130 200 400 TOO 1000 1.1 4J 0.9 121 o.*7 3.11 1.1 1M (A3 2.40 Ml L34j 149 on 341 0.71 L77 a2 2.63 0.9) L27 1.06 loo MS 1.9S 149 0.74 L91 0.63 L24 0.66 2.13 0.73 IJ4 0.16 1.64 1.0 160 149 0.61 2-44 043 1 19 046 1.79 063 1.33 0.72 Ml oxt M3 1 1.09 F Vitas -- DR 2) PrwNraCkM 100 200 400 TOO 1000 L3 9.0 L0 6461 LOS 6.60 L34 ltTi L64 M0I Ml 4471 441 14 6.47 1.41 3.0 1.47 4.7) 1.61 4.10! 1.91 2J0 347 242 1.17 0.9 44) 0.99 341 0.76 342 1.04 L7t aao 3A4 Ml 2-51 0.91 IM M3 L23 104 231 142 241 LOS 1.99 Ll_ 1.94 146 l IJS-14* dW HmdOmt far Wnwnaa W * adiai TaM. I. 142 143 Ml 1.14 0.99 j 141 049 1 0.91 L4S 241 L07 L12 1.66 1.72 l.4| 1.44 3.191 342 3.7) 342 L63 240 miSS. LOS 1.40 146 149 1.4) 1.14 147 1.03 1 1.14 1 67 M3 M6 M3 -- Lf2 3.14 M7 L39 L63 214 1.93 L13 241 1 63 1 II 1 44 -- $.99 647 ? 13 4.31 4.79 3 14 3.0) 347 3 6t L34 240 ; ^ CTL027267 LnilSctl PVC Pipe Ni Page II Back To Basics: Pipe Stiffness Fundamentals M Dave Ei kstctn Technu uf Director mance under load. Pipes with inches of trjvel representing the Where: E = Modulus of ten relatively high stillnesses will I) deflection and ihe inches of sile elasticity of CONFIGURATION deflect less under a constant length of the sample. the pipe mate The configuration compo Each PVC Pipe News we make an ardent effort io slay topical with subject matter. Your input to us has prompted the load, or 2) require a higher load to produce a constant deflection. The converse is true for pipes of relative low stiffness. F.xamnle. Take a one tool long sample of KK) inch inside diameter pipe. Say the force io reach 5 percent deflection is one rial. psi. I = Moment of Inertia per unit length, in-1 nent of pipe stillness is governed by the moment of inertia (I) and the mean radius (r). Configuration or shape development of this new feature, In order to have values half ton. the pipe stiffness is- Mean radius of design is not new to structural "Back to Basics." Here, each standardized for use in design the pipe, inches analysis of any kind including edition we plan to take an in- and to compare different pipes, pipe. The trend for the past few depth look at some fundamental aspect of PVC pipe design. Keeping pace with chang one of the variables in stiffness determination (force or deflec tion) must be set. Historically, P.S. = F/Ay .5 tons (100 inches x 5%) (I foot) years, however, has certainly been one of increasing attention to this facet of stiffness. The ing times and needs, the PVC Industry is ever introducing new applications and product lines. the standards have set deflection as the constant and defined a value of 5 percent of the original 1000 lbs. 5x12 in2 result of this attention has been an assortment of product lines manufactured in profile wall This updating requires a firm outside diameter. foundation in design basics for The American Society for 16.67 psi Stiffness physically is a configurations. The intent, as function of the strength of the before, is to offer the same the novice and the seasoned Testing and Materials (ASTM) material from which the pipe is stiffness with less material (as PVC pipe designer alike. Standard D24I2. "Standard Test Likewise, take a six inch made (E) and the configuration compared with solid wall pipe) This edition we examine the Method for External Loading sample of 8" ASTM D3034. in which it is manufactured (I in the case of sanitary sewer very beginnings in PVC non- Properties of Plastic Pipe by SDR 35 sanitary sewer pipe. The and r). Let s look separately at pipe. The profile configurations pressure pipe design: Parallel-Plate Loading.'' deline pipe stiffness is defined in these variables and its current also can offer a more cost ates test protocol and calculation standard D3034 as 46 psi. direction within the pipe effective performer for new Pipe Stiffness in a method for determining the Calculate the minimum force industry. markets, for example lower Flexible Conduit standard pipe stiffness value for required in the D24I2 testing to stiffness pipes for storm dram plastic pipe. Immediately meet minimum pipe stiffness. RAW MATERIAL applications. The relative flexibility or evident from the standard's title For illustration purposes, a stiffness of a pipe has long been is the verification that this is a P.S. - F/Ay Pipe grade compounds for trip back to my high school recognized as critical in determining the reaction of pipe to its environment, as well as. pipe only parameter. Test specimens are placed in a 46 psi parallel-plate loader with no side non-pressure applications today F/Av range tn modulus of elasticity (I.D. x 5%) (6 inches) (E) from 400.000 psi to about physics class is in order. All those years ago in Des Moines, Iowa, we were told to hold a the environment to the pipe. Pipe stiffness is defined as: support. To best understand the test 46 P*' " F [8.4 - 2(.24)J .05 x 6 560.000. The PVC resin used in the making of all these piece of paper (8 1/2 x II variety) cantilever by one of the and. therefore, the parameter it compounds is basically the short ends. Our not so lovely PS. * F/Ay defines, a look at units is in order. Although commonly F 46 psi x 2.376 in^ same. It is the compounding, assistant, my parents having both the additives themselves viewed my grade school Where: P.S. pipe stiffness, psi expressed in psi. stiffness is most accurately expressed as F > 109.3 pounds and the technology with which performance had sentenced me they are combined, that make to an all boys school, was F force, per unit pounds per inch-inch. Pipe Mathematically, pipe stiff the difference in end product instructed to place a quarter on length. Ibs/in. stiffness is produced by ness can be expressed as. performance. the far end. (Unlike the Ay change in y deflecting a sample to 95 Due to several changes in experiments on TV. go ahead axis. in. percent of its original vertical the non-pressure pipe markets of and try this one at home.) The outside diameter. The pounds The pipe stiffness is then a force to produce the deflection is P.S. 0.14! late, it has become more feasible obvious result was that paper to compound specifically to that isn't very good at the structural rating of the deflection perfor- noted and divided both by the market. Resin costs, improved requirements of quarter holding. performance additives, com Now we were instructed to Force Main surges per hour for 50 years. given safety factor. See pages pounding technology and larger take the same piece of paper and DR 25 is adequate for this 120 to 129 of the afore non-pressure markets are among alternately fold approximately example. mentioned Handbook for further the factors involved. More and 1" strips up and down across the (Continued from Pane W) In this particular example, a details of cyclic fatigue design. more the users will be seeing width. Re-enactment of the product meeting AWWA C900 compounds specifically geared quarter placement proved struc wall thickness ill. by using a was specified. DR 25 is the EXTERNAL LOAD to the end use. turally far superior in this con form ot the ISO equation. lowest pressure class available CONSIDERATIONS Virtually any aspect of figuration. Same material, more meeting this standard. Lower pressure rated products (higher change to physical properties structurally efficient profile. External loads are seldom cames with it the possibility of The analogy to pipe holds DR's) which meet ASTM D the critical design variable for consequence, positively or nega good one more step in that there 2241. "Standard Specification PVC pressure pipes. However, tively. to some other aspect. It is was additional work required to for PolyfVmyl Chloride) (PVC) in a force main application imperative then to monitor all manufacture the profile. In pipe DR S' dimension ratio required design peak hoop stress, psi Pressure-Rated Pipe (SDR Series)." are available. They may offer a similarly conserva where intermittent flow and severe cyclic surge conditions may exist, which may be either aspects when changes are made. Regulatory-wise that is accom plished by standardizing the also, the economics of profile are normally in excess of (hat for solid wall. Diameter, P peak internal pirtsaw, J tive yet more economical design. positive or negative, it is allowable compounds to be used required stiffness, material (P|t. psi In this 7500' project the Peak internal pressure in required pumping pressure (Ppl dependent upon change its is reduced uniformly over the appropriate to consider external load. The above example verified by specification of cell classi fication. The cell classification defines physical property ranges savings, extrusion cost. etc., all become variables which ulti mately dictate overall selection. velocity in a given DR. We will check the adequacy of the largest DR. lowest pressure class, first. Given: DR 25 has a P| of 89 length of the project. For DR 25 Pp is 31.1 psi. At the midway point in ihe line the working pressure will be 0.5 x 31.1 or 15.55 psi. If the peak internal that DR 25 would meet the internal pressure requirements. The external loading w ill consist of the earth load tdeadi and traffic load llivei. It is given that in many areas of performance, therefore, providing the check and balance required. It should be noted that it is this reasoning that has defeated some recent Having reviewed the mech anism of pipe stiffness and the variables involved and their role, the user can better judge the appropriateness of different psi. pressure is reduced by- 15.55 psi. the frost depth is approximately attempts to legislate additive product prototypes for different Therefore DR-^+ 1 the required DR becomes: DR i 2ft 182) *I 89- 15.55 two feel and that the line will be buried beneath paved roadways. Therefore, highway (H20i loading w ith three to four foot of levels or filler content tn favor of sticking with cell class specification. Additionally, the filler content approach ignores end use applications. The present and future hold manynew opportunities for the PVC pipe industry. Opportunities that DR-mi-, DR 33.19 cover is the combined loading which must be considered. Table I ton page IOi lists the technology of compounding and leaves the user open to the risk of an incompetent com both the Industry and the users are anxious for us to accept. Pipe sulfness and its role in DR - 27.56 calculated deflections tor C900 pounder and closed to the buried pipe performance? Maybe By calculating the pressure PVC pipe under various advantages of a competent one. next time, or how about HDB Therefore, as long as the gradient and utilizing an itera combined loadings. A check of Only cell classification places determination in pressure pipe PVC pressure pipe product has a tive design procedure, one may DR 25 under 2 to 4 foot ot cover "as compounds'' performance or something else? Let me hear DR less than 27.56. it will meet determine the most economical with an H20 live load reveals requirements. from you! the given requirements of 10 design while maintaining a iConnmied on Pave I2i CTL027268 UniBtU PVC Pipe News Pape 12 * Pressure Fittings: A Non-Corrosive Connection Memion PVC lo Bob t Kreykenbohm and you get much more than his sudden attention. Quite obvious, even on the telephone, is his unbridled enthusiasm for the term. In his position as Water Superintendent for the Sandwich Water District, which provides drinking water lo the Cjpe Cod resort community of Sandwich. Massachusetts. ***** Kreykenbohm is a self-confessed proponent of PVC pipe and finings. PVC fittings? "You bet." k Kreykenbohm says. "We've just installed 52 of them in about 7 miles of 6-in. and 8-in. water Pembroke (Continuedfrom Page 31 material qualities as the small diameter, such as good flow characteristics and no susceptibility to corrosion." This made PVC an ideal choice for the dual force main. Construction of the eight mile dual PVC force mam began in March of 1987 and was completed on schedule in March of 1988. Phase one of the construction included clearing and demucking along the majority of the length of the proposed route. A tremendous amount of overgrowth existed in the undeveloped areas. Next came the process of demucking. The first three feet of trench was a soft organic material. Following this was the removal of several feet of lime rock. As the photos show, there was a constant battle to keep the ditch dry. The water table is near the surface in South Florida, as you might guess. The bedding for the pipe consisted of 8 to 12 inches of gravel. This material was brought up to the springline of the PVC pipes. The photos reveal that spacing between the two mains was such that the granular material could be adequately placed in the haunch areas between them. The initial backfill, which consisted of a sandy granular material, was placed to a few inches above the pipes and native final backfill material followed. Upon completion of the installation the dual force main was pressure tested. The line was required to undergo a 200 psig pressure test for the first half mile from the pump station. The remainder of the line was tested at ISO psig. The dual PVC force main has been in service just a little under one year now. The smaller force main is now nearly full and the larger force main will be opened soon. According to Mr. Michael F. Estok. Pembroke Pines Director of Public Services. "The line has lived up to our expectations. It is working just fine." transmission lines and they tested out perfectly. No leaks. Lower cost." "But then again, that's what we expected, even though I'm told our installation is the very first in North America for these fittings." Several years in development and testing stages, the new PVC fittings are injection molded through a unique technology. The fittings are produced with a hydrostatic design basis (HDB) of 4000 psi comparable to PVC pipe manufactured to meet AWWA C900. The PVC fittings are designed for Class 150 (DR 18) PVC pressure pipe conforming to AWWAC900. Altogether. 40 6-in. and 12 8in. finings were used (both Ts and elbows). The water main, now installed and operating, provides water from gravel pack wells to three different subdivisions at an average pressure of 78 psi. The main, though designed to carry 1.000 gal/min. for fire flow reasons, is averaging "well below" that, according to Kreykenbohm. "Over the last several years, we have replaced an estimated 2 1/2 miles of 2 - 2 l/2-m. cement- "Overall cost of this par ticular instaUation was around 23. percent less than ductile.* Kreykenbohm says. "A lot of that savings can be attributed directly lo the PVC fittings. "Ductile finings require mechanical joints, and need to be boiled together. This takes time." he reasons. "The PVC fitting joints are virtually identical to the pipe. We simply push fitting and pipe together using a crowbar, installation is buildup mod thereby Wed--sS^ tosma'lamy experience wurdf yean alt well see is maybe a dun' film. Periodic flushing, done on a yearly basis, ukes care of that.' Corrosion is of no concern to Kreykenbohm. The PVC fmings are not subject to galvanic or electrolytic corrosion. No wrap pings or coatings were required. Kreykenbohm foresees no need for regular maintenance of Force Main monly used to determine thrust forces in other types of pipe are (Continuedfrom Page II) utilized for PVC. Fittings and valves must be blocked against those forces. that the maximum deflection is PVC pressure pipe is offered 2.3 percent, well below the in both IPS and C.I.O.D. regi acceptable limit for PVC pressure mens. It is currently manufactured pipe. It also reveals that this in (hameien up 30 inch. It may deflection would occur at tlM be incorporated into moat existing minimum depth of cover with without the necessity for lowest E\ worst soil compecthM* (had inventory of finings. combination, listed in the tabtas PVC pressure pipe offers the Therefore, if the pipe is instalM physical properties required to with class IV material bedding withstand both inietna! pressure and haunching or better, and at and external load. Because it is least a slight compactive effort, produced in a range of pressure the external loading is not critical. ratings, cost efficient combina PVC pipe, under normal tions can be selected by the engi temperature conditions, can with neer for specific applications. stand a vacuum. However, when a High safety facton may be main vacuum occurs it acts in addition tained without over designing. As to the external loads. It will sel can be seen in the example above, dom be a critical design variable. cost effectiveness can be achieved For additional information refer to an article entitled. 'A Discussion of PVC Pipe Under \hcuum," in our Summer 1988 issue of the Uni-Bell PVC Pipe News. without a complicated design procedure. We hope the example comes in handy. For more information concerning PVC force main design please give us OTHER CONSIDERATIONS a call. lined wrought iron pipe w uh PVC in our 125 mile system." he notes. "In all cases, we have upgraded to the larger 6-in. and K-in. sizes tor fireflow purposes." The big reason the Board of Water Commissioners of the District has readily agreed with Kreykenbohms recommenda tions to go almost exclusively with PVC pipe, and now fimngv is cost Long-term corrosion free service provides added ' aluc. "On a per-foot basis, our costs on ibis particular installation would range from SI6 to S3? per foot. Thai includes all matenaK. labor, top cover extras and so ou." Kreykenbohm ays. "The txgje* material savings come at intersections where you have the majority ot tittingx. "I would estimate a 50 percent sax mgs os er ductile fittings on the complete project." he notes. But Kreykenbohm s biggest con sideration was "the labor factor, where it's not unusual lo pas S25 an hour." he points out In most cases, the District handles ns own installation of water mains The men in charge: Kreykenbohm. that simple and fasl. and there were no leaks.'' he emphasizes. Testing of the completed mains was done at 150 psi in several 20-mm. stages. Pressure was raised and held for that time, then dropped, then repeated. The Class 150 PVC fittings offer long-term hydrostatic strength, satisfying all contem porary safety standards for municipal water systems throughout the L'.S. r.-wi Canada. Quick Burst Strength rating is 755 psi 15.21 MPa) minimum, when tested in accordance with 4STM DI599. Minimum wall thickness ol the fining body is at least 125 percent the wall thickness of Class 150 (DR 181 C900 pipe of the same size. The fittings conform to UNI-B-12. Recommended Standard Specification for Polyvinyl Chloride (PVC) Pressure Fittings." as well as CSA 8- 137 ?. "PolsiVinyl Chloride) PVC Injection Molded Gasketed Fittings for Pressure Applica tions." Kreykenbohm is also counting on other benefits any kind. "Die life expectancy of ihe mams is fores er. " he says. "and this includes the finings. In the future as the community grows, the only factor making them obsolete might be lire fiow capacity. But thats a long wjy off. You and 1 wont be around, that's for sure." Did the Um-Bell member company PVC pipe or fittings present any unexpected problems on this job. Kreykenbohm is asked. His answer is. "None. Deliveries were on time and their on-ihe-job service support was great. What I like best is. whai they say they'll do. they do. that goes from the president on down." Kreykenbohm interrupts his own comments and pauses: Oh. there is one thing I want to mention. Their pipe is ioo slippers. Our laborers walk on it in the trench I keep thinking someone will slip and fall and get hurt. "Seriously [hough." he concludes, "lhat was my only major concern on the whole job ' The same methods com along with Assistant Water inherent in PVC products. The Supenmendent. Dan Mahoney. glass-smooth surface of the pipe CTL027269