UNDERGROUND ARTERIES: STORY OF TRANSITE PIPE ASBESTOS CEMENT

[Music] [Music] so [Music] clean pure water at a twist of the wrist few of us realize or stop to think what a remarkable engineering achievement this represents the housewife who couldn't get through the day without water hardly gives a thought to where it comes from or the extent to which her family's well-being depends on it nor does the man of the family pay much attention providing the suppliers plentiful and the bills reasonable and as far as this little fellow is concerned problems of unfailing supply plumbing costs maintenance and such belong to another world [Music] even the roaring destruction of fire does little more than momentarily highlight the urgent need for an efficient and dependable water supply [Music] this casual acceptance of our water systems on the part of the public is a tribute to the men who design build and operate our water systems their job at making our modern water supply networks the finest in the world is not an easy one at meetings in municipal office buildings or city hall discussions and decisions embrace every problem from locating the source of water to delivering it to the point of use these cool woodland brooks these shaded springs become the larger waters and rivers that serve as sources of supply in many areas sometimes nature creates natural reservoirs or shield for man to create his own captive water supply by constructing dams across convenient valleys but whatever the source of supply it is merely the beginning of a new water system the water must be treated to make it palatable and sparkling to soften it to give it unquestioned purity from the source to the ultimate consumer the journey is a long and complicated one the water must be transported with a minimum of waste and after treatment must be protected against contamination this is the job of the transmission and distribution mains that vital portion of the system which because it lies underground goes unnoticed by the community the efficiency and economy of the entire undertaking depends on the pipelines to deliver water economically and dependably the pipe comprising these lines must meet critical engineering requirements the first of these is quick economic installation the initial opportunity to achieve savings in the cost of the system second structural strength the line must withstand the pressure of water from within and earth and traffic loads from without third tight joints efficient operation requires that leakage in the line be kept to an absolute minimum fourth maintained flow capacity the purpose of the line is to deliver required volumes of water at adequate pressures and at minimum pumping costs and this high delivery capacity must be maintained throughout the years fifth long life the pipe should have a high degree of corrosion resistance to maintain its initial strength and structural integrity and sixth protection of water quality for purity must be safeguarded from one end of the line to the other these then are the requirements of a water pipe if it is to serve dependably and efficiently and here is the pipe that pays extra dividends from the time of installation to providing a dependable supply of pure water year after year transite pressure pipe the indestructible materials from which transit is made asbestos portland cement and silica and the technical skill and know-how that go into its manufacturer are the reasons why transite pipe exhibits such unusual characteristics even among minerals asbestos is a paradox it is as tough and hard as the mother rock in which it appears as veins or seams yet when it is processed opened up as the miners say it resembles cotton or wool fibers but possesses the tensile strength of piano wire and there's hardly a chemical in common use that will change its unusual properties to any appreciable extent next playing an important role is portland cement this material which might well be called plastic stone has proved itself a strong and lasting construction material through the years when we visit one of a number of factories where transit pressure pipe is made we can quickly see that rigid control and up-to-date techniques are keynotes in the manufacturing process shipments of asbestos fibers are received from one of a number of johns manville mines here a bag containing one of the several selected types is emptied into a willowing machine where the dry fibers are further opened up and separated one from another by mechanical dispersion next in tanks such as these a number of different types of selected asbestos fibers are blended in accurate predetermined proportions this process is followed by another carefully controlled dry mixing operation in these chambers where portland cement and silica are combined with the blended asbestos fibers in exact proportions as one step in a program of continuing automatic controls each batch of dry ingredients is weighed accurately and the result registered on a paper tape not only for a check at the time of mixing but also for a permanent record next water is added and a slurry formed which is continuously agitated to ensure complete distribution of all the ingredients consistently uniform distribution is an aim achieved throughout transit pipe manufacture and here as at every step of the way it is johns manville's experience and technical knowledge that count heavily the slurry is deposited uniformly on a wide endless belt forming a continuous sheet excess quantities of water are drawn off as the slurry passes over a line of vacuum heads at the forming end of the machine the belt carries the material to the smooth surface of a steel mandrel on which the pipe is made the size of the mandrel determines the size of the pipe under pressure created by hydraulic rams the pipe wall is consolidated into a dense homogeneous structure this carefully controlled pressure removes all excess water and creates a material of uniformly high density strength and toughness transit pressure pipe is made in diameters of from 4 to 16 inches and in classes for maximum working pressures of 100 150 and 200 pounds per square inch the process continues until the pipe has reached its specified thickness which is signified by the red light indicator on this electronic instrument once the correct thickness is reached the pipe forming operation is completed and the mandrel with the pipe on it is removed from the machine another mandrel automatically taking its place conveyors take the newly formed pipe to this special electrolytic equipment designed and developed by johns manville here an electrical method of loosening without stretching prepares the pipe for its easy removal from the mandrel it remains on the mandrel as it is rolled to a rack where the pipe is permanently identified its size and the class of service for which it is designed are clearly marked here the removal from the mandrel takes place this is easily done since the pipe has already been loosened by the electrolytic method the mandrels are later rolled away and automatically fed back for reuse now by means of a suction lift the lengths of formed pipe are removed from the racks and are placed temporarily on a special platform where they are left for a brief period of air curing the final step in curing has taken place in these pressure steam tanks this process developed by johns manville uses live steam to add further chemical stability to the inherent properties of transite under the action of this controlled pressure steam curing process the silica which was originally added to the mix combines chemically with the free lime of the portland cement to produce more durable compounds and a highly stable and corrosion resistant product the cured pipe is now ready for machining to dimensions this semi-automatic operation cuts the pipe to length and machines each end to size so that it will match exactly the coupling with which it will be used careful inspection and close dimensional checking for accuracy are carried out at this time as an extra safeguard of quick easy assembly after its dimensions have been closely checked transit pressure pipe is subjected to a series of tests to confirm its ability to meet all normal service requirements and the unpredictable stresses sometimes imposed on water lines one of these is the beam test applied to each length of pipe in those sizes where flexural stresses are an important consideration as the load is applied at one third points of the pipe note how the pipe bends then with the load released the pipe springs back to normal position the hydrostatic pressure test is another test that is applied to every section of transit pipe transit pressure pipe is designed and tested to meet the requirements of the american water works association specification in this test each pipe section is filled with water and the pressure is raised to three and one half times the pipe's maximum recommended working pressure and held at that point for a specified time in the case of class 150 pipe for example every section is subjected to a pressure 525 pounds per square inch for a period of five seconds in addition from each 300 lengths which have passed the routine hydrostatic test one pipe is selected and tested to four times the pipe's maximum recommended working pressure in the case of class 150 pipe shown this selected length is first tested to the routine 525 pounds per square inch for five seconds it is then again tested to 600 pounds per square inch where it is also held for the full five seconds then it is immediately retested at the routine pressure as before thus thorough and rigid checking and testing assure the transit pressure pipe will perform under service conditions that it has the strength characteristics for which it has been designed and engineered just as important as the pipelines themselves are the means by which they are joined together to form the completed line recognizing this johns manville design developed and achieved a major engineering advance in solving this important water main problem from the standpoints of installation ease and long service life this is known as the ring tight coupling coupling sleeve stock which has been made of the same material as the pipe and manufactured on the same machines is cut into sections by specially designed equipment each coupling is then machined to precise dimensions at the same time grooves are machined within the coupling sleeve to receive the rubber rings the grooves are accurately dimensioned as to depth and as to with to position the rubber rings and keep them permanently in the proper place each coupling is gauged and checked for conformance with strict specifications to assure positive trouble free assembly in the trench the factor of safety in the ring tied coupling must be the same as in the pipe itself consequently each coupling must pass a rigid hydrostatic test now we come to another essential part of the ring tight assembly the rubber rings they too are subjected to a series of specification and performance tests by both supplier and johns manville here they are stretched to half again their original circumference and while in this stretch condition inspected and checked in addition to the stretch test the ring is given a compression test to determine that the ring will react satisfactorily to the conditions that will be encountered in service when the various tests on the transit pipe have been completed the seal of the national board of fire underwriters is affixed denoting approval by that organization next the pipe moves to the loading platforms for shipment at each of the johns manville transit pipe factories this is a daily site shipments of transit pressure pipe on their way to the job to meet the initial requirement of an efficient water carrier economic installation this begins literally with delivery to the job site because of its relatively lightweight a great number of sections can be carried per truckload in unloading and in all subsequent operations handling is easier than with other heavier types of pipe these men have little difficulty with a full 13 foot section of 12-inch class 150 pipe for all but the larger diameters lowering into the trench does not require the use of mechanical handling equipment this means that available hand labor can be used to a maximum extent but the outstanding installation advantage of transit is the factory made joint which only requires assembly on the job the ring tight coupling this ingenious coupling provides the simplest quickest means ever developed for permanently joining pipe as we shall now see in the following above ground demonstration here two sections of six inch transit pressure pipe are about to be joined together each pipe end is wiped clean each is lubricated a specially prepared johns manville lubricant is used one that is completely safe in fact water quality is not affected in any way the rubber sealing rings are easily inserted in deep accurately dimension grooves within the coupling next the coupling is placed in position and both pipe ends and coupling are brought together then one of the pipes is pushed home by means of a simple bar and wood block and the joint is made movement is stopped automatically by the shoulders on the pipe ends finally the completed joint is checked all around to make sure the rings are properly positioned that's all there is to it the job is done let's look at a cross section of the ring tie joint and see what actually goes on inside during assembly and what the results are as each lubricated pipe end moves easily into place the rings in the coupling grooves are compressed making a really tight seal it does not leak because the rings are locked in place where they belong the shoulder on the pipe end stops the pipe at exactly the right point stops it automatically provides automatically for expansion another popular method of assembly that can be used with all sizes is to bell ahead this simply means mounting a coupling on one end of a section of pipe it can be done in the trench or on top it provides a firm socket into which final assembly can be easily made in assembling larger sizes of pipe a simple coupling puller can be used lubrication is the same as for the other methods the puller is first used to bell the pipe without removing the puller the chain can be transferred and used to draw the loose pipe section into the coupling with the ring tight assembly pipelines lock securely yet remain flexible and resilient to cushion against shifts or movements resulting from earth settlement or vibration because of this flexibility the pipe can be laid around wide curves or it also makes it possible to avoid obstructions when laying the line on this job the assembly of the pipe has been so rapid that the pipeline crew is pressing the trenching machine in fact this kind of rapid assembly of transit pipe often enables the same foreman to supervise both excavation and pipeline quick assembly means also that the trench need to be open only a minimum of time which helps avoid cave-ins or freezing in city streets and along highways such speedy installation means shorter interruptions to traffic minimizes disturbances valves hydrants and fittings embedding the ring type design are available and when they are installed in the line this ring-type design offers extra dividends in the form of simple quick assembly here a valve is being put into the line full 13 foot lanes are used on either side of the valve heating equipment tools and time required for making pore joints are completely eliminated however if desired poor joints can be made with transite mechanical joints can also be made with transite when such joints are used requiring short stubs in place of full lengths it's important a pipe material be easy to cut and machine a variety of efficient tools is available that do the job quickly and easily transite pipe cuts cleanly and sharply and does not fracture it can be drilled and tapped using standard equipment either while the pipe is dry or when it's under pressure in this demonstration a three-quarter inch corporation stop has been tapped into eight inch class 150 pipe the corporation stop is then subjected to a direct tensile pull as the load is increased one thousand two thousand three thousand the corporation stop holds tightly finally at three thousand nine hundred pounds the corporation stop pulls out a close examination of the pull out shows that the threads have not failed or stripped instead they've maintained the sharp clean characteristics which are essential to strong service connections where large cut-ins are required transite lends itself readily to such operations here a valve is being inserted into a supply line which is under full working pressures and flow once the line is laid the real tests of the inherent values of water pipe actually begin the economies of installation have been affected that book is closed now the lifelong economies begin that account is never closed let us examine the manner in which transite measures up to the requirement of structural strength first comes the ability to resist stresses caused by internal pressures these may vary considerably in magnitude particularly when pumping pressures are boosted to meet fire flow requirements or when the sudden opening or closing of valves creates surges in the line the inherent strength of this pipe capable of meeting such demands is verified by the factory tests in which each pipe and coupling is subjected to three and one-half times the maximum recommended working pressure but water pipe must also resist external loads the weight of backfill and pavement and the heavy loads and shocks of traffic we must return to a johns manville plant to appreciate how this asbestos cement pipe meets these requirements here a one foot section of eight inch class 150 pipe is being subjected to a crushing test the procedure used is the three edge bearing method specified by the american society for testing materials as the load increases the pipe withstand stresses far above those it would normally encounter in service here finally at eight thousand four hundred pounds ultimate strength is reached examination of a piece of pipe taken from the corporation stop pull-out test reveals an important reason for transit strength the large number of asbestos fibers which serve as a reinforcement their uniform dispersion throughout the wall structure and their unusually high tensile strength all combined to produce the characteristics necessary to meet the many requirements for strength and toughness in service constant vibration from traffic and settlement of earth also impose stresses on a line which tend to cause leakage surveys indicate that as high as 25 percent or more of the water pumped into many systems becomes unaccounted for as far as any financial return is concerned some of the so-called unaccounted for water goes into such public services as street flushing and fire fighting but a considerable portion is just plain lost water directly attributable to leaky joints the effects of leakage can be cumulative seeping water may undermine and weaken the earth supporting the pipe if leakage continues serious rupture may result the ring tight coupling plays an important part in protecting the line from such difficulties the flexibility and shock absorbing features of this joint reduce beam stresses in the line as a whole and in the individual sections of pipe they also relieve the coupling itself from flexural effects that frequently cause joint loosening and leakage this typical bridge crossing demonstrates the shock absorbing characteristics of the joint ring tight couplings remain tight even under conditions of almost constant vibration in many cases extreme conditions even earthquakes have not affected this tightness in any way in three recent upheavals for example at eureka tehachapi and arvin california headlines proclaimed widespread destruction yet no damage to transit water mains was reported nor are such developments anything new perhaps the most striking illustration of the integrity of a transit line occurred during the famous inyo kern earthquake of 1946 which according to seismographic records was one of maximum intensity an installation of more than sixty miles of this pipe ran through the area later examination showed that both pipe and joints had come through unscathed there were no leaks the flexibility of the line had permitted it to roll with the punch but today's water lines must do more than resist the stresses set up by internal pressures and by external loads and shocks they have the positive function of delivering to the community the necessary flow of water not only for present needs but for expanding future requirements as well the ability to perform this duty efficiently is influenced to a considerable extent by the flow characteristics of the pipe selected to do the job the amount of water which will flow through a line depends on two things the force pushing the water through the line and the internal smoothness of the pipe itself as we have already seen a steel mandrel imparts a smooth interior surface to the pipe during manufacture this smooth interior surface offers minimum resistance to the flow of water and gives the pipe an exceptionally high flow capacity its flow coefficient expressed in terms of the hazen williams formula is c equals 140 but it is not enough that the pipe possess an initial high flow coefficient it is essential that it maintain its flow capacity permanently it should be immune to tuberculation a form of internal corrosion the small nodules or tubercles which grow on the interior of pipe carrying tuberculating waters reduce its flow capacity in two ways by setting up verbals and minute eddy currents which increase internal resistance and by decreasing the effective inside diameter of the pipe thus further restricting the flow to compensate for the adverse effects of tuberculation it becomes necessary to increase pumping pressures and consequently operating costs transite pipe assures protection against tuberculation because it is non-metallic and therefore cannot tuberculate waterworks projects involve the expenditure of substantial sums of money and financing over extended periods of time if community indebtedness is to be kept to a minimum and if water rates are to remain low the system must outlive the financing period one half or more of the money spent for the average water system goes into the supply and distribution lines therefore these lines must be of lasting materials the most important single measure of the durability or life expectancy of an underground water line material is its resistance to corrosion transite pipes corrosion resistance stems from the ingredients used in its composition and from the methods employed in its manufacture it is during the steam curing process that the presence of silica becomes so important under chemical reactions induced by the high temperature steam the silica unites with the free lime ordinarily found in portland cement products as a result compounds far more chemically stable are formed these are the calcium silicates which impart a corrosion resistance to transit not found in ordinary cement products or obtainable through ordinary methods of curing the chemical stability of transite may be demonstrated in the laboratory by both alkalinity and leaching tests in this test the reagent will turn a definite purple in the presence of free lime the small amount dropped on each slab tells its own story a more quantitative method of showing the effectiveness of steam curing is by means of standard leaching tests equal quantities of ordinary neat cement and transit which have been pulverized are subjected to a progression of identical tests in which the free line is leached out of each mixture for purposes of comparison the results of these tests may be plotted as a graph here are the cumulative results on a sample of ordinary cement when the same test is conducted on transit samples the marked reduction in free lime content is evident it is this greater chemical stability that accounts for its durability and long life underground soil corrosion tests have also been carried out the united states bureau of standards has over a period of years buried many different materials at selected sites among the numerous materials tested were samples of pipe including transite after 13 years exposure to the most corrosive soils encountered during the tests any true measurable effect on the transit samples was slight in comparison to the other pipe materials the long-term integrity of a pipe material however is nowhere proved more completely than by its total performance record under actual operating conditions here for example is a piece of a four-inch transit pipe which was removed for observation from the water distribution system of the fast-growing southern california community in this system many types of pipes were used severe maintenance problems due to corrosive soils made it necessary for the community to check periodically on pipeline materials test evaluations on pipe removed included bursting and crushing tests in reporting the results of this work the general manager and chief engineer of the water district said upon careful examination of asbestos cement pipe which had been in service for approximately 15 years at each of three test sites with what was considered to be the most corrosive soils in the area no evidence of outer surface softening of the pipe was noted all specimens withstood by a substantial margin the hydrostatic test pressures required at the factory for the particular class of pipe another case is that of a large canadian city where the detrimental effects of soil corrosion on pipe materials are well known and have been the subject of intensive and continuing study for years in the spring of 1932 a feeder main of transit was installed in a particularly corrosive area after 14 years a section of pipe was taken out and shipped to the factory for the same series of tests to which the pipe had been originally subjected upon completion of this work the city engineer reported in view of the fact that no deterioration in either the carrying capacity or physical characteristics of the pipe has been noted it is not possible at this time to fix the future service life expectancy for this pipe on the basis of the performance rented to date however it is reasonable to anticipate a life expectancy of many times that already obtained today after more than 25 years in corrosive soil this pipe is well on its way to fulfilling the engineers expectation because some industrial pipelines in the oil industry for example are subjected to unusually severe conditions they may be regarded as accelerated tests of the life expectancy of pipe materials pipe must resist corrosion from within as well as from without transit has been used successfully for many years for removal of corrosive salt waters from oil field operations in the coal industry corrosive drainage waters must sometimes be pumped from underground mine operations while these waters may be so corrosive as to limit the life of other pipe materials to a few months transit installations have withstood such service continuously for more than 25 years with little or no evidence of deterioration in any system the care expended to produce healthful water might be wasted if the quality of that water were affected when conveyed through the mains transite pipe can be depended on to safeguard the quality of the water it carries it cannot rust and cause discoloration or impart objectionable tastes it's asbestos cement composition and method of manufacture give it the chemical stability that recommends it for the conveyance of safe potable waters the ring tight coupling also protects the quality of the water since the materials used offer no focal point for the growth of harmful bacteria by meeting this final requirement that of maintaining the original purity of the water it conveys transite completes the picture of the modern water main material we have seen how it combines quick economic installation structural strength tight joints maintained flow capacity long life and the safeguarding of water quality to meet the demand new factories have been built and production facilities expanded as transit has demonstrated its ability to measure up to the requirements of the modern water line material as in all lines of human endeavor there is in the waterworks industry a forward-moving determination to improve a job already well done waterworks officials responsible for safeguarding public health and advancing community well-being have two objectives always in mind improving water service on the one hand and affecting lower costs on the other to achieve these ends communities in ever-increasing numbers are turning to the use of transit pipe designed to help accomplish this purpose it is in substantial measure contributing to the progress of the waterworks industry [Applause] you