Document 3eBbvX30QaMDX7YQErz0KgOqy

Section 1 . . . . Page 3. .. . Introduction to Design Manual for TRANS!TE*Transmission Pipe Section 2 ... . Page 5.... Design and Selection Practices for TRANSITE Transmission Pipe SPECIFIC PIPE SELECTION DESIGN DATA Appendix A. . .Page 11... TRANSITE Transmission Pipe, Manufacture and Properties Appendix B. . . Page 13... Flow Powergraph and Head Loss Chart Appendix C. . . Page 17. .. Earth Load Determination Appendix D. . . Page 21. . . Live Load Determination Appendix E. . . Page 23. . . Bedding Classes and Bedding Factors Appendix F. . . Page 25... Water Hammer and Surge Analysis and Control Appendix G. . . Page 31. .. Air in Pipelines Appendix H.. . Page 33. .. Combined Loading Curves Appendix I . . Page 41. . . Typical Illustrative Problems on Pipe Selection Appendix J. . . Page 43 . . . Pipe and Coupling Dimensions and Weights Appendix K... Page 45 ... System Specifications Appendix L. .. Page 49 ... Thrust Control and Other Installation Details Appendix M . . Page 55 . . . Reducers and Adaptors Appendix N... Page 57 ... Warranty Appendix 0. . . Page 59 . . . References 'TRANSITE is a registered Johns-Manville trademark for its brand of asbestos-cement products. r Johns-Manville has recognized the need of water works and other indus tries for large asbestos-cement pipes in a wide range of strength classifica tions. With a wide selection of pipes to choose from, maximum economies can be obtained by the design engineer through thorough analysis and selection of pipe strengths that closely match engineering requirements for each section of his pipeline. To meet this need for economy in material and efficiency in long-term service, TRANSITE Transmission Pipe was developed. It is currently sup plied in six strength classifications and eight sizes, from 18" through 36". This manual presents the latest techniques in design and selection of TRANSITE Transmission Pipe for transmission and feeder mains, pressure sewer lines, industrial process lines, et cetera. It has been prepared to pro vide the designer with the engineering data needed to readily select the most economical pipe with adequate strength fora particular service which is compatible with the best engineering practices. 1 2 V r O s Introduction to Design Manual for "TRANSITE" TRANSMISSION PIPE DEFINITIONS AND ECONOMIC CONSIDERATIONS The main function of a piping system is to transport a fluid such as water from one point to another. Piping systems can vary from simple runs to grids which are complex in nature, in designing a pipe line, the designer must examine all parameters in volved in his particular system. The design concept outlined in this manual offers the designer more selectivity in meeting his en gineering requirement while at the same time bal ancing it against economics of the installed pipe line. This concept has evolved from the long ex perience that Johns-Manville, numerous engineers and users have had with asbestos cement pipe in many different services. The design concept involves taking a closer look at the various external and internal loads to which a pipeline is subjected. The engineer is then able to design the pipeline and select the classification of pipe that best fit his needs. Because Johns-Manville offers a broad range of strength classifications and sizes in its line of TRANSITE Transmission Pipe the designer has the freedom of selection necessary to provide the most efficient system in relation to engineering requirements and installed costs. A further discussion of TRANSITE Transmission Pipe specific benefits, manufacture, and properties is presented in Appendix A. OBJECTIVES OF DESIGN MANUAL Some of the information needed for the design of a piping system includes the necessary hydraulic properties of the system, the structural require ments, the service environment, materials to be used with alternates, and the technical data neces sary for proper material and equipment selection. All of these facts are evaluated and the system de sign brought to the proper balance between require ments and cost. The desire of the piping system owner for a safe, maintenance free, and efficient system at a minimum cost may then be satisfied. This manual has been prepared to be of maximum assistance to the design engineer for the efficient selection of TRANSITE Transmission Pipe. It con tains basic and yet convenient design procedures with suggested safety factors for the rapid selec tion of the most economical pipe to adequately meet the job requirements. Sufficient detail is presented in the text and appendixes such that the engineer may verify each step in the design procedure. Sample design problems are included for demon stration. Also included in the manual are engi neering and dimensional data, recommended in stallation procedures, material specifications and installation specifications. 3 4 $c ; H" ' %' i- vV *V*t'* <, Design and Selection Practices for "TRANSITE" TRANSMISSION PIPE The two major design factors that form the basis for transmission pipe selection are pipe diameter and pipe strength. These factors are by no means independent, but for convenience they will be con sidered separately. A. PIPE DIAMETER SELECTION To determine the required diameter of a specific pipe in a system, information relating to volume of fluid flowing, velocity limitations, friction factor of pipe, and ground profile must be available. Material and pumping costs are also factors which effect the selection from an economic standpoint. The various factors are studied, judged in relation to one an other and the size of pipe selected based on the engineers evaluation of all the factors involved. In fluencing the designer's decision would, of course, be the results of studies on pumping costs vs. pipe diameter, future growth in demand and cost of surge control equipment if required. Appendix B (Figure 2) presents a nomograph of the Hazen-Williams formula for assistance in de termining the pipe diameter, head loss, and flow velocity for various quantities of flow. In piping systems which have long runs with relatively few fittings and accessories, the recommended value of C is 150. A second nomograph in Appendix B (Figure 1) includes a relationship for determining horsepower required to overcome friction head loss for any given value of "C". The yearly power cost to compensate for friction loss of head can be determined by converting horsepower required to kilowatt hours per year and multiplying by the power cost per KWH. The conversion factor is shown on the nomograph. _ Example problems are also shown in the Ap pendix for illustration. B. PIPE STRENGTH SELECTION After the pipe diameter has been established, the designer must determine the strength of pipe by next evaluating internal and external loads on the pipe. Following is a listing of these loads to be con sidered. Separate sections are presented in this manual showing methods to determine the actual value of these loads in a convenient manner accord ing to accepted engineering practice. The combined loading principle which employs these computed in ternal and external loads is described. The method to most easily apply this principle for the rapid and accurate selection of pipe strength for given service conditions is presented on a step by step basis with illustrative examples. LOADS ON TRANSMISSION PIPE AND FACTORS AFFECTING LOADS 1. External loads a. Earth loads 1. Depth of cover 2. Width of trench 3. Weight of soil 4. Type of soil 5. Bedding condition b. Live load 1. Magnitude of load and type of load 2. Depth of cover 3. Impact factor 4. Bedding factor 2. Internal loads a. Operating pressure b. Hydraulic gradient c. Surge 1. Velocity 2. Pump characteristics 3. Surge control devices 4. Pipe material, wall thickness, diameter 5 COMBINED LOADING PRINCIPLE At any given moment a pipe in service is generally subjected to a combination of internal and external loads. Various combinations of earth load, live load, operating pressure and water hammer can be de termined within reasonable limits in a well designed system. The pipe selected fora particular job must stand up to the combinations of steady and tran sient loads as calculated for that job. Adequate safety factors should be incorporated as consistent with known service conditions and the ability to control installation and transient load conditions. The maximum tensile or compressive stresses in duced in the pipe wall by internal pressure and external loads have been found to be additive ac cording to widely accepted rigid conduit theory and testing. Consequently, the magnitude of internal pressure that can be safely resisted by a rigid pipe such as TRANSITE will vary inversely with the mag nitude of external loading applied simultaneously. It has been found through combined hydrostatic and crush loading tests to ultimate pipe failure that the behavior of TRANSITE Transmission Pipe may be shown by the Schlick formufa which states: w = W-^-p-5 Where: P = the internal hydrostatic design pres sure for the pipe when no external load exists--psi. W = the external crushing design load for the pipe (3-edge bearing test) when no internal pressure exists--Ibs/ft of pipe. p = the internal hydrostatic pressure for that pipe when an external crushing load (w) is acting simultaneously--psi. w = external crushing load for the pipe when an internal pressure (p) is also acting on the pipe--Ibs/ft of pipe. This may be interpreted graphically by the fol lowing: Each of the factors that contribute to the external or internal loading of the pipe are considered sepa rately in the next section. 6 EXTERNAL LOADING Earth Loads The earth in the trench back-fill produces a crush load on the pipe. Formulas developed by Marston have been shown to be reliable for computation of these loads. There are two general forms of the Marston for mula that apply individually depending on trench width and depth conditions. Appendix C presents these formulas and their method of use. The first formula shown in Appendix C applies to what is. generally referred to as the "trench load" condition and usually occurs when the trench width is less than two to three times the conduit width, depend ing on the conduit size and depth of trench. The assumption is made that friction between the back fill and trench walls will affect the load on the pipe. The second formula in Appendix C applies to wide trenches and is referred to as the "positive project ing conduit condition." The trench walls are as sumed to have no effect on the load on the pipe in wide trenches. The earth load computed under this condition is theoretically the maximum load on the pipe for a given depth of cover. Appendix C illus trates use of these formulas with a sample problem. For the designer's convenience, computations have been made for the earth load on each size of pipe from 18" to 36". Various trench widths have been used with earth covers from two to twenty feet. These charts are also shown in Appendix C. Weight of earth was taken as 120 lbs /ft3 for the cal culations. Corrections for other earth weights may be made by simple direct proportion. <* v: I Live Loads Cement Pipe." The amount of backfill load a given Live loads are usually caused by a wheel from a ve pipe will withstand is further increased from the hicle passing over the trench backfill. The loads test strength values, however, due to the load occur over a relatively small bearing area on the distribution effect of the bedding under and ground and, therefore, may be considered as con around the pipe. To determine the supporting ? centrated. The load from the wheel that actually strength of the pipe and bedding system, there reaches the level of the pipe decreases rapidly with depth of cover. The accepted formula used to compute the magnitude of this load is presented in Appendix D. The formula includes a factor for impact which may be caused by the wheel hitting a bump directly over the pipe. The factor "F" to be used for impact decreases with depth of cover. In accordance with fore, the crush strength of the pipe is multiplied by a factor (bedding factor) reflecting the quality of the bedding. Appendix E presents illustrations of the four bed ding conditions in common use. This chart is fol lowed by a table of bedding factors applicable to each bedding condition, i.e. these represent the magnitude of upward adjustment of crush load over the three-edge values. AASHO recommendations no impact factor is used for depths of cover greater than three feet. (See INTERNAL PRESSURE Appendix "D" for depths of cover of one to three For simplicity in design and selection of TRANSITE feet.) Transmission Pipe, the internal pressure may be As recognized, the impact factor rapidly dimin separated into two categories: ishes with depth because of the effective dampen 1. Operating Pressure ing characteristics of the earth. 2. Water Hammer or Surge Crush Loads--Characteristics of TRANSITE Each will be determined separately. Transmission Pipe 1. Operating Pressure The crushing strength of TRANSITE Pipe is de The operating pressure is that pressure which exists pendent upon its wall thickness and the inherent under normal or steady conditions of operation. strength of asbestos-cement as a structural mate rial. The test used to establish the crushing strength of TRANSITE Pipe is found in ASTM C500, "Standard Methods of Testing Asbestos- The pressure may be induced by pumps, from grav ity such as the head created by a reservoir or ele vated water tank, or combination of both pumps and gravity. Under a purely gravity situation, the 7 pressure in the line at a given point is somewhat higher when there is no flow or conditions are static. Under static conditions the pressure at a given point, measured in feet of head, is equal to the dif ference in the elevation of that point and the water surface level at the reservoir. Under flowing condi tions the pressure at the point under consideration is reduced by the amount of friction and other en ergy losses resulting from the flow of water from the reservoir to that point. The magnitude of this loss in head may be found by use of the HazenWilliam's nomograph in Appendix "B" Figure 2. 2. Water Hammer or Surge Surge pressures are of a transient nature and are caused by unsteady or changing conditions in the pipeline. The names "water hammer," "surge," or "transient pressure" are often used interchange ably to refer to these pressures of brief duration, but often of considerable magnitude. A variety of conditions may cause surge pressures. These in clude a valve opening or closing, sudden movement of air in a line, or a pump starting or stopping. Transient pressures are often a controlling fac tor in the selection of a pipe strength. For this rea son, a pipe system should always be analyzed for surge pressure determinations and the results used in pipe selection. There are numerous methods for control of surge pressures in the line. Consideration should be given 8 to use of these devices to limit pressures to an acceptable level. Economics plays a major role in this area. Various designs may have to be bal anced depending on the complexity of the system to yield an economical and efficient design. Appendix F presents a discussion of water ham mer with emphasis on how it may be analyzed and methods of control. Although the subject is dis cussed in some detail and an illustrative problem included involving surge pressure control by timing a va'lve closure, the subject is too complex to be thoroughly covered in the design manual. It is sug gested that control of surge for any transmissionsystem be discussed with surge control equipment manufacturers or consultants in this field. The effects of surge in a pipeline, however, should not be ignored as possible neglect of this factor may result in severe damage to the system. Also, because of the number of variables involved in creating water hammer pressures and the abil ity to regulate their magnitude with proper controls, it is not recommended that fixed water hammer al lowances based on pipe diameter or some other sin gle criterion be used. AIR IN PIPELINES Air can enter pipelines from several sources and in doing so, can create problems such as reduced ca pacity and magnified surge plus other serious oper ational difficulties. The pipelines should be in stalled to grade rather than to follow the earth sur face, so as to reduce the number of locations where air can accumulate in a line. Care should be taken to insure that all air possible be eliminated from the pipeline both during initial filling of the line and during operation. Appendix G describes ways air can enter a line and suggests solutions for proper control. COMBINED LOADING CURVES As discussed above it has been demonstrated sat isfactorily by tests that TRANSITE Transmission Pipe conforms generally to the "Schlick formula" for combined loading. Numerous tests have estab lished values for internal hydrostatic design pres sure with no crush load applied (P) and external crush design loads with no internal pressure ap plied (W) for all diameters and strength classifica tions. These values represent the end points on the combined loading curves with the-intermediate points computed by use of the Schlick formula. (It should be noted that all values used for P and W represent a conservative interpretation of the test data.) The intermediate points on the curve, w and p, are the combinations of crush loading and in ternal pressure the pipe will withstand when these loads are applied simultaneously. In Appendix H graphs are presented for each diameter of pipe from 18" through 36". On the graph for each diameter of pipe a combined load ing curve is drawn for each strength classification of that size pipe. The vertical axis represents the internal hydrostatic design pressure (P) and the horizontal axis the external design 3-edge bearing crush load (W). The chart presented before the graphs lists the values of P and W for the strength classifications of each pipe size. The method for selection is outlined in the section on the "Use of Selection Charts" below. SAFETY FACTORS Safety factors normally are applied by the engineer to his computed design values of crush and internal pressure to be resisted by the pipe in service. These factors protect against unforeseen loads that may be placed on the line at some time in the future, and for other contingencies such as improper construc tion. It is the engineers' prerogative to select what safety factors he feels should apply to a given system. Considerable field experience as well as exten sive laboratory work has yielded a wealth of infor mation on the behavior of TRANSITE Pipe. For this reason the following suggestions on mini mum safety factors are made for use in selecting TRANSITE Transmission Pipe. Suggested Safety Factors for use with TRANSITE Transmission Pipe Selection Type of Load Operating pressu re+water hammer combined with earth load + live load Safety Factor Hydro Crush 2.0 1.5 Note that safety factors are applied to both hy dro and crush simultaneously in the selection of TRANSITE Pipe since the combined loading prin ciple is applicable. Note also that water hammer and live load, which are both transient load condi tions, are considered as acting simultaneously for design purposes here. Since the likelihood of both occurring at the same time is very small, an addi tional conservative element is introduced into the design. USE OF SELECTION CHARTS FOR ECONOMICAL DESIGN After all loads on the pipe have been computed (Op erating pressure, water hammer, earth load, live load) select the most economical strength of pipe to meet the service conditions. Use the applicable procedure depending on the safety factors used. A. Selection procedure using safety factors as sug gested by Johns-Manville 1. Add operating pressure and water hammer (OP + WH) (See Appendix F). 2, Add earth load and live load (EL + LL) from Appendixes C & D. 9 3. Enter the combined loading graph in Ap pendix H for the appropriate diameter of pipe. Plot as one point the values from 1 and 2 . When using the lefthand scales, be sure to multiply the operating pressure and water ham mer by the Jchns-Manville suggested safety factor of 2.0. When using the bottom scale be sure to multiply the earth load plus live load by the Johns-Manville suggested safety factor of 1.5 and divide it by the bedding factor. 4. The point will lie between the curves for two pipe strengths. Select the higher strength of the two. This represents the most economical selection consistent with engineering require ments. B. Selection procedure using safety factors as se lected by the designer. 1. Add operating pressure and water hammer (OP + WH) (See Appendix F). 2. Add earth load and live load (EL + LL) from Appendixes C & D. 3. Multiply (OP + WH) times safety factor in hydro. 4. Multiply (EL + LL) times safety factor in crush and divide by the bedding factor to be employed. This compensates for the fact that W on the graph was established on the basis of three-edge bearing tests. 5. Enter the combined loading graph in Ap pendix H for the appropriate diameter of pipe. Plot as one point the values obtained from steps 3 and 4. 6. The point will lie between the curves for two pipe strengths. Select the higher strength of the two. It is recognized that additional design proce dures may be employed by using various combina tions of the external load and internal pressure. Selections may be made, however, by essentially following the above procedure and varying the load combinations as described. PIPE AND FITTINGS Appendix J presents detailed dimensional data on pipe and couplings in sizes 18" and larger in all the available strength classifications. Weights of pipe are also included. Details and data on steel and cast iron fittings can be obtained from the applicable AWWA or other standards. If any additional information or classification is desired, please contact your J-M representative or Customer Service Center. SYSTEM SPECIFICATIONS As a convenience and guide to the engineer, system specifications have been prepared and are included in Appendix K. These are: 1. Material Specifications for TRANSITE Transmission Pipe. 2. Installation Specifications for TRANSITE Transmission Pipe. INSTALLATION Installation and construction techniques are pre sented in detail in the "Transite Transmission Pipe Installation Guide" published by Johns-Man ville. This booklet is available to contractors and others concerned with the installation of TRAN,SITE Pipe. Supplementary information follows. THRUST CONTROL Thrust control is a critical factor in the design of pressure line's. Drawings of general types of thrust control that can be employed where particular conditions are encountered are presented in Ap pendix L. Combinations of these arrangements may be utilized where multiple fittings occur or where standard methods cannot be applied. Thrust control is dependent on pipe size, the type of soil, and the maximum anticipated pres sure (considering surge and test pressures) in the pipeline. 10 iHrijiMiati I'if! mmm a TRANSITE Transmission Pipe--Manufacture and Properties Johns-Manville TRANSITE Pipe is an asbestoscement product. It is composed of an intimate mix ture of Portland cement, silica and asbestos fiber. The material is completely free from organic or me tallic substances. Figure 1 presents a flow chart depicting the method of manufacture of TRANSITE pipe. The pipe is formed under pressure on a steel mandrel creating a dense wall with a smooth interior sur face. Final curing of the product is done in an auto clave employing high pressure steam (100 psi) for dimensional stability and chemical stability. The properties of TRANSITE Transmission Pipe that make it particularly advantageous include the following: a. TRANSITE is an asbestos-fibre-reinforced prod uct. The asbestos fibres used have a tensile strength as high as 400,000 psi and the fibres are oriented in the material in such a way as to utilize their high tensile properties for maximum reinforcement and stress resistance. The high strength of TRANSITE may be demonstrated by examining the hydrostatic and crush strengths of each size and strength of pipe. A chart with these values is shown in Appendix H. Continuous plant testing assures the maintenance of these high values. b. The wide range of strengths available within each pipe size has been graduated so that maximum economies can be achieved by selection of the proper pipe to do the job. c. The high corrosion and chemical resistance of TRANSITE pipe make it highly resistant to corro sive soils and waters. This gives assurance of a long useful life with high maintained flow. d. The Ring-Tite joint system with rubber rings as sures a tight system with no leakage. Machining to close tolerance at the factory together with rigid quality control assures an installation that in addition to being tight goes together fast. Rub ber ring joints also add flexibility to the line which can be of great value under conditions of shifting soils and vibrations. e* The initial Hazen-Williams "C" factor of 150 for TRANSITE Lines which have relatively few fit tings and accessories, may be depended upon by the designer to be maintained over the entire life of the pipe. Therefore, initial efficient designs with TRANSITE do not have to be altered because of consideration of any change in the "C" factor by interior surface roughing. TRANSITE main- tains a smooth interior surface providing lower pumping costs. IZ\ n ~co "O 03 c I -2 a 5 O (0 -^5* Oc) *6 2 Q-^6 co JE3C *c c *cU e X (0 a._ ss .5 2 c 3u. oc 1o3 'o aCO *0) oc> 'a I.9c- s g . B 1 ... *u *E= Zo 1w3 a E a E js E cn c E oc a 'a. CO EI o3 == " c E * o c0. oX o L_ JZ u tco .9TO to O> E Js A 8 J-? i eII 8.1 ts -S* --1 N_2wO1 -->% * t3 *o> .9aa. -u CO 2 13 co coO' .p* a 5-- 3-g -i iS -E >>c% "O^>o o 2" g to C JC ,5> .og= *co o Oo -*I= -C P J, a g -I o uj * o o2 gt *2 OC) *w<<** w to c . J> S|<' 3 K C(0L 2*g e. x" o A c | f Ul 0> c "sOff jo II ac I o s 5 -2-2 A 8) C P*s -D o -o O o J- 3co 13 x *n* S uj cn 2 < < -J .2 E e> o - ei w m in oE co UJ Q "oO *E 3 D h O <u. ts Q. _2o (u1) 3 o .2 C Ou Z< S UaJ a ui H to z < o <cD i= -Ce r .:Qc <B 2 "D 5o2 _c>*-oCacL ^O) oc > II .5 .9 o -c o = w OO3 O) I.E o> a j- u. E g E 2 S2? o 3 a> .'>o TC3 E3 > X 2 -o *- 2 ' E O) o c Q- a 3 _3a 2-S -C U) o ** >2 E -a S oc 3o o ^r o O 3 T3 C> js s .2 a 23 <o Q--X .2 .9 o 2 ^ J, w DrCe O 2 " s o o- -5 s Hat < x o 5 .5 s S |o 2 cIo _.5Q C o o *3D O E o-| J2z (AI o> ::ii w -wnA o; g sI ~.S! .? O4) -- *coon o *5 d o 2P O uj 3 2 Dm) J2, 5' 5w "O OC) 20 S o ^ o 6 I1 ^ 1c = I g i > O " .2 > s> t o |i| o o 5 cn > c o oo s * W O 1a. a. * 2 SI CL s m ^ in to co 12 Fig. 1 FLOW POWERGRAPH KILOWATT HOURS PER YE/1 R, MULTIPLY BY THE CONSTANT 6532 42- Derived from the Williams & Hazen Formula by A. T. Clark & M. B. Frost 48-4 13 ILLUSTRATIVE PROBLEMS ON PIPE DIAMETER SELECTION PROBLEM 1 The minimum elevation of the surface of a reser voir is 198 feet. A TRANSITE transmission line (C = 150) is to carry water by gravity to a city distribution system, a distance of 5 miles. The pressure at the entrance to the distribution sys tem is to be a minimum of 75 psi. Design flow is 6000 gallons per minute. Determine the size of pipe required and the velocit.. of design flow. Solution: Head Prom Reservoir Head Delivered to Distribution System 2.31 x 75 198 ft. 174 ft. Allowable Loss of Head 24 ft. Length of Line = 5 x 5280 = 26,400 ft. Allowable loss of head per 1000 ft. (C = 150) = 24/26.4 = 0.91 ft. Enter nomograph in Figure 2 on either top or bot tom horizontal axis at 0.91 ft. loss in head per 1000 ft. Go vertically to intersection of 6000 gal lons-minute. This lies between 27" and 30" di ameter pipe. Therefore use 30". This will deliver about 6500 gpm at a velocity of about 3.4 ft. per second. PROBLEM 2 Water is to be pumped from one reservoir to an other by means of a TRANSITE transmission line 50,000 ft. long. The lower reservoir is at eleva tion 100 ft. and the upper at 250 ft. Design flow is to be 5000 gpm and the velocity is not to exceed 51/2 ft/sec. Determine a) the size of pipe re quired, b) the maximum head at the pump, c) the horsepower and annual power cost required to overcome friction only (not elevation difference) and d) the annual power cost to overcome friction in the line if C = 100 (assume power cost = $.02 per kwh). Solution: a. Enter nomograph in Figure 2 at 5000 gal/min. Proceed to intersection at 5Vz ft/sec. This falls between 18" and 20" diameter pipe. Use 20" pipe. This will give a velocity of about 5.3 ft/sec. at design flow and head loss of 3.3 ft/1000 ft. for C= 150. b. Elevation difference = 250--100=150 feet Friction loss = 50x3.3=165 feet Max. head at the pump =315 feet c. Horsepower and power cost to overcome fric tion: Use nomograph in Figure 1--5000 gpm =7,200,000 gal/day. Enter nomograph at C=150, 20" diameter and 7,200,000 gal/ day. Find horsepower/1000 ft. as indicated. This is 3.4 HP/1000 ft., converting to Kwh= 3.4 ft. x 6532=22,210 Kwh/year/1000 ft. 22,210 x $.02=$444.20/year/1000 ft. Total power cost/year=$444.20 x 50=$22,210.00/year for C = 150. d. Repeat procedure for C = 100, 20" diameter and 7,200,000 gal/day horsepower/1000 ft. = 8. HP/1000 ft. 8.0 x 6532 = 52,200 Kwh/yr./1000' 52,200 x $.02 = $l,044.00/yr./1000' Total power cost for 1 year = $1,044.00 x 50 = $52,200.00/yr. for C = 100. PER THOUSAND FEET OF LENGTH 15 Fig. 2 FRICTION LOSS OF HEAD CHART COEFFICIENT OF FLOW C == 150 DERIVED FROM THE WILLIAMS AND HAZt'N FORMULA - V I.318CR ' S ' In transmission piping systems which have long runs with relatively few fittings and accessories, Transite Transmission Pipe has a coefficient of C= 150. Because of Transited asbestos-cement composition, this initial high flow capacity cannot be reduced by tuberculating water -- the chief cause of loss in carrying capacity. This helps maintain the carrying capacity provided for future requirements and is an important factor in mini mizing pumping costs. Note: Loss of Head values derived from this chart are for coefficient of flow C = 150. They may be converted to loss of head for other coefficients of flow by means of the following multiplying factors: 1.13 for C = 140 1.77 for C= 110 1.30 for C = 130 2.12 for C = 100 1.51 for C = 120 2.58 for C =90 3.22 for C =80 5.46 for C = 60 Note: Diameters derived from this chart are for co efficient of flow C = 150. These may be converted to diameters for other coefficients of flow by means of the following multiplying factors: 1.03 for C = 140 1.13 for C = 110 1.07 for C = 130 1.18 for C = 100 1.10 for C = 120 1.22 for C =90 1.30 for C =80 1.41 for C = 60 LOSS OF HEAD IN FEET PER 1 CONVERSION FACTORS Multiply. By. Acre--feet.......................................................... 325,851 .... Barrels (42 gallons) per day ..............................02917 ...... Barrels (31 gallons) per day................................. 02153 ...... Barrels (45 gallons) per day................................. 03125 ...... Cubic feet of water............................................. 7.48052 .... Cubic feet per second.......................................448.831 .... Cubic feet per second.......................................0.64617 .... Feet of Water.......................................................62.43 ........ Feet of Water.........................................................0.4335...... Gallons of Water.................................................. 8.3453...... Gallons of Water................................................231 ........... Gallons per minute........................................... 2.228 x 10'3 Horsepower ....................................................... 0.7457 ...... Horsepower .......................................................6532 ......... Million Gallons perday....................................... 694.4 ......... Pounds per square inch.....................................2.31............ To Obtain Gallons Gallons per minute Gallons per minute Gallons per minute Gallons Gallons per minute Million gallons per Day Pounds per square foot Pounds per square inch Pounds of water Cubic inches Cubic feet per sec. Kilowatts Kilowatt hours per year Gallons per minute Feet of water ( 5i3i 16 < THE MARSTON FORMULAS FOR COMPUTATION OF EARTH LOADS ON A CONDUIT 1. W, = Cdw(B,i)2 Trench condition (trench width usually less than 2 to 3 times conduit width) (See Chart below for Cd determination.) Cc= 1.892-5^-0.96 2. Wc = Ccw(Bc)2 ' Projecting conduit condition (where trench width greater than or equal to "transition width") in which: "Transition Width"--That width corresponding to the load computed by the trench formula equal to the maximum earth load as calculated by the pro jecting conduit equation. That is, for the same depth of cover, trenches wider than the "transition width" will not yield a greater load on the pipe than the projecting con duit load. Wcand Wd = loads on the pipe in pounds perfoot Cc and Cd = load coefficients dependent on a variety of variables such as height of backfill, width of conduit and/or trench and soil characteristics.* w = weight of soil in pounds per cubic foot Bc = width of the conduit Ba = width of the trench H = Height of fill above top of pipe *For earth load charts the following conditions and con stants were used: rsap = 0.70, which is an average condition for "projecting conduit" loads, where: p = projection ratio. rsd = settlement ratio. ku = 0.1924 conservative for "projecting conduit con dition." ku = 0.1300 conservative for "trench condition" where: k = Rankine's ratio of lateral earth pressure to vertical pressure. u = coefficient of backfill internal friction, w = 120 lbs/ft3 0.1 0.2 0.3 0.4 0.5 0.6 0.8 1 2 3 45 COEFFICIENT--Cd Graph for Determining C,, Coefficients Each of the above curves represent Cu values for ku and ku'. A represents 0.1924 for granular ma terials without cohesion: B is 0.165 maximum for sand and gravel; C is 0.150 maximum for saturated top soil; D, 0.13 maximum for ordinary clay; and E, 0.110 maximum for saturated clay. The symbol u', is the coefficient of friction between the backfill material and the sides of the ditch. 17 ILLUSTRATIVE PROBLEMS An 18" TRANSITE Transmission Pipe is to be in stalled in a 3 ft. wide trench under 8 feet of cover. The backfill is ordinary clay with a weight of 120 pcf. Determine the earth load on the pipe. Solution: The load must be computed 2 ways using the Marston formulas for the trench condition and that for the projecting conduit condition. The engineer, knowing the job conditions and degree of inspec tion, should decide which load applies, a. trench condition Wd = Cdw (Bd)2 obtain Cd from graph using curve D and C,, = 1.9 Wd = (1.9) (120) (3)2 = 2100 Ibs/ft b. projecting conduit condition Wc = Cew (Bc)s where Bc = O.D. 18" pipe = 1.7 ft. Cc = 1.892-^-- 0.96 = 1.892-4;-- 0.96 = 8 Dc 1.7 Wc = (8) (120) (1.7)2 _ 2800 Ibs/ft TRENCH COVER 2' 2'6" 3' 4' 5' 6' 7' 8' 9' 10' 12' 14' 16' 18' 20' EARTH LOADS (LBS/LIN FT) Weight of earth taken equals 120 lbs. per cubic foot. Correction for other earth weights may be made by simple direct proportions. BOLD FIGURES INDICATE MAXIMUM EARTH LOAD FOR DEPTH OF TRENCH Pipe Size 18" i.D. 2'6" 490 640 810 1000 1200 1350 1500 1600 1725 1850 2050 2200 2300 2400 2500 2'9" 3'0" 640 835 1110 1320 1520 1690 1850 2000 2120 2360 2570 2720 2840 3000 1240 1450 1700 1900 2100 2250 2400 2675 2900 3100 3275 3400 TRENCH WIDTH 3'3" 3'6" 4-0" 1610 1865 2090 2320 2510 2725 3020 3280 3515 3720 3995 1640 2050 2300 2525 2750. 2950 3300 3600 3900 4150 4350 2825 3230 3550 4000 4400 4800 5100 5350 4'6" 5'0" * 3635 4440 5220 5640 6040 6400 6040 6830 7450 5'6" 7620 TRANSITION WIDTH 2'5" 2'8" 2'10" 3'1" 3'5" 3'8" 3'10" 4-0" 4-1" 4'3" 4'5" 47" 4-9- 5'0" 5'2" TRENCH COVER 2' 2'6" 3' 4' 5' 6' 7' 8' 9' 10' 12' 14' 16 18' 20' 18 2'9" 545 705 870 1110 1320 1520 1690 1850 2000 2120 2360 2570 2720 2840 3000 3'0" 890 1250 1450 1700 1900 2100 2250 2400 2675 2900 3100 3275 3400 3'3" 1330 1610 1865 090 2320 2510 2725 3020 3280 3515 3720 3995 Pipe Size 20" I.D. TRENCH WIDTH 3'6" 3'9" 4'0" 1750 2050 2300 2525 2750 2950 3300 3600 3900 4150 4350 1770 2210 2515 2765 3040 3240 3660 4050 4350 4620 4860 2220 2655 3000 3300 3550 4000 4400 4800 5100 5350 4*6" 3095 3545 3980 4660 5200 5640 6040 6400 5'0" 4810 5760 6450 7050 7450 TRANSITION 5'6" WIDTH 2-s" 2'10" 3'0" CO A 6640 7500 8410 oq in 3'8" 3'11" 4-1- 4'3" 4'5" 4'6" 4'10" 5'1" 5'4" 57" TRENCH COVER 2' 2'6" 3' 4' 5' 6' r 8' 9' 10' 12' 14' 16' 18' 20' 2'9" 570 745 870 1110 1320 1520 1690 1850 2000 2120 2360 2570 2720 2840 3000 3'0" 730 915 1250 1450 1700 1900 2100 2250 2400 2675 2900 3100 3275 3400 3'3" 1330 1610 1865 2090 2320 2510 2725 3020 3280 3515 3720 3995 3'6" 1380 1750 2050 2300 2525 2750 2950 3300 3600 3900 4150 4350 Pipe Size 21" I.D, TRENCH WIDTH 3'9" 4'0" 4'6" 1860 2210 2515 2765 3040 3240 3660 4050 4350 4620 4860 2325 2700 3000 3300 3550 4000 4400 4800 5100 5350 2795 3260 3725 4140 4660 5200 5640 6040 6400 5'0" 4210 5160 6000 6450 7050 7450 5'6" 6100 7020 7950 8460 6'0" 8920 TRANSITION WIDTH 2'9" 2'ir 3'2" 3'6' 3'10" 4'r 4'4" 4'6" 4'7" 4'9" 5'0" 5'3" 5'5* 5'6" 5'8" TRENCH COVER 2' 2'6" 3' 4' 5' 6' 7' 8' 9' 10' 12' 14' 16' 18' 20' 3'0" 630 805 955 1250 1450 1700 1900 2100 2250 2400 2675 2900 3100 3275 3400 3'3" 810 1010 1330 1610 1865 2090 2320 2510 2725 3020 3280 3515 3720 3995 3'6" 1010 1400 1750 2050 2300 2525 2750 2950 3300 3600 3900 4150 4350 3'9" 1490 1940 2210 2515 2765 3040 3240 3660 4050 4350 4620 4860 Pipe Size 24" I.D. TRENCH WIDTH 4'0'' 4'6" 5'0" 2030 2400 2700 3000 3300 3550 4000 4400 4800 5100 5350 2550 3080 3480 3790 4140 4660 5200 5640 6040 6400 3620 4130 4660 5400 6000 6450 7050 7450 5'6" 4660 5740 6750 7410 8000 8460 6'0'' 6800 7850 8910 9600 6'6" 10000 TRANSITION WIDTH 3'1" 3'3" 3'5" 3'9" 4'1" 4'5" 4'8" 4'10" 5'0" 5'2" 5'5" 5'8" 5'11" 6'1" 6'2" TRENCH COVER 2' 2'6" 3' 4' 5' 6' r 8' 9' 10' 12' 14' 16' 18' 20' 3'3" 710 895 1040 1330 1610 1865 2090 2320 2510 2725 3020 3280 3515 3720 3995 3'6" 905 1095 1400 1750 2050 2300 2525 2750 2950 3300 3600 3900 4150 4350 Pipe Size 27" I.D. TRENCH WIDTH 3'9" 4'0' 4'6" 5'0" 5'6" 1540 1940 2210 2515 2765 3040 3240 3660 4050 4350 4620 4860 1600 2050 2400 2700 3000 3300 3550 4000 4400 4800 5100 5350 2200 2785 3110 3480 3790 4140 4660 5200 5640 6040 6400 3385 3900 4300 4700 5400 6000 6450 7050 7450 3980 4590 5190 6060 6750 7410 8000 8460 6'0" 6'6" 6390 7550 8300 9000 9600 7560 8800 9960 10890 7'0" 10000 11180 TRANSITION WIDTH 3'5" 3'6" 3'8" 4'1" 4'6" 4'8" 5'1* 5'3" 5'6" 5'7' 6'0" 6'3" 6'6" 6'8" 6'10" 19 TRENCH COVER 2' 2'6" 3' 4' ' 5' 6' r 8' 9' 10' 12' 14' 16' 18' 20' 3'6" 755 965 1150 1400 1750 2050 2300 2525 ' 2750 2950 3300 3600 3900 4150 4350 4'0" 1185 1675 2050 2400 2700 3000 3300 3550 4000 4400 4800 5100 5350 4'6" 1680 2335 2800 3110 3480 3790 4140 4660 5200 5640 6040 6400 Pipe Size 30" I.D, TRENCH WIDTH 5'0" 5'6" 6'0" 2340 3005 3500 3900 4300 4700 5400 6000 6450 7050 7450 3665 4320 4840 5260 6060 6750 7410 8000 8460 4980 5660 6800 7550 8300 9000 9600 6'6" 6990 8320 9210 9960 10890 7'0" 8320 9610 10980 11890 7'6" 10980 12300 TRANSITION WIDTH 37" 3'10" 3'11" 4'5" 4-8" 5'0" 5'5" 57" 5'10" 6'1" 6'5" 6'9" 7'0" 7'3" 7'5" TRENCH COVER 2' 2'6" 3' 4' 5' 6' T 8' 9' 10' 12' 14' 16' 18' 20' 3'9" 810 1050 1220 1540 1940 2210 2515 2705 3040 3240 3660 4050 4350 4620 4860 4'0" 1060 1290 1675 2050 2400 3000 3300 3550 4000 4400 4800 5100 5350 5575 4'6" 1815 2335 2800 3110 . 3480 3790 4140 4660 5200 5640 6040 6400 5'0" 2445 3050 3500 3900 4300 4700 5400 6000 6450 7050 7450 Pipe Size 33" I.D. TRENCH WIDTH 5'6" 6'0" 6'6" 3205 3920 4460 4840 5260 6060 6750 7410 8000 8460 3925 4640 5400 5900 6800 7550 8300 9000 9600 5610 6070 7450 8350 9210 9960 10890 7'0" 7550 9030 10110 11060 11890 7'6" 10470 12120 13020 8'0" 13390 TRANSITION WIDTH 3'10" 4'1" 4'3" 4'6" 5'1" 5'5" 61" 6'3" 6'5" 610" 7'2" 7'5" 7'9" 711" 00 in o 00 o CM TRENCH COVER 2' 2'6" 3' 4' 5' 6' 7' 8' 9' 10' 12' 14' 16' 18' 20 4'0" 920 1130 1325 1675 2050 2400 2700 3000 3300 3550 4000 4400 4800 5100 5350 4'6" 925 1145 1550 1950 2335 2800 3110 3480 3790 4140 4660 5200 5640 6040 6400 5'0" 5'6" 1950 2555 3050 3500 c 3900 4300 4700 5400 6000 6450 7050 7450 2555 3340 3920 4460 4840 5260 6060 6750 7410 8000 8460 Pipe Size 36" I.D. TRENCH WIDTH 6'0" 6'6" 7'0" 3340 4160 4900 5400 5900 6800 7550 8300 9000 9600 4950 5760 6430 7450 8350 9210 9960 10890 5760 6540 8150 9170 10110 11060 11890 7'6" 8150 9750 11000 12150 13020 8'6" 9750 11330 12900 14140 12900 14510 TRANSITION WIDTH 4'3" 4-4" 4'7" 4'11" 5'3" 5'8" 6'0" 6'2" 6'8" 6'10" 7'4" 7'8" 7'11" 8'2" 8'6" LIVE LOADS--COMPUTATIONS W8C = CB-^- Where: Wc = Load on the conduit in pounds per lineal foot P = superimposed concentrated load in pounds F = Impact factor used as a contingency against the effect of a dynamic load (See Table for impact factor) L = Length of the conduit (use 3' for conduits greater than 3' in length) C, = Load coefficient which is a function of the width of the conduit and the height of the backfill (see the following Table for values of Cs for pipe 18" to 36" in diameter and covers of 2' to 20') Cs VALUES OF LOAD COEFFICIENTS C,, FOR CO NCENTRATED SUPERIMPOSED LOADS CENTERED VER1 ICALLY OVER CONDUIT PIPE SIZE ID 2' 2'6" 3' DEPTH OF COVER 4' 5' 6' 8' 10' 12' 16' 20' 18" 0.391 0.289 0.221 0.136 0.092 0.066 0.038 0.025 0.017 0.010 0.006 20' 0.422 0.316 0.241 0.150 0.102 0.073 0.042 0.027 0.019 0.011 0.007 21' 0.436 0.327 0.251 0.157 0.107 0.077 0.044 . 0.029 0.020 0.012 0.0075 24' 0.478 0.362 0.280 0.177 0.120 0.087 0.050 0.033 0.022 0.013 0.0080 27' 0.510 0.392 0.306 0.195 0.133 0.096 0.056 0.037 0.025 0.014 0.0085 30" 0.543 0.423 0.332 0.213 0.147 0.106 0.062 0.041 0.029 0.016 0.010 33" 0.563 0.446 0.353 0.230 0.159 0.115 0.067 0.045 0.032 0.018 0.011 36" 0.590 0.470 0.375 0.248 0.171 0.124 0.073 0.049 0.035 .0.020 0.012 F IMPACT FACTOR TABLE* DEPTH OF COVER IMPACT FACTOR (F) 1'--2' 2'-3' 3' or more 1.2 1.1 1.0 'A.A.S.H.O. STANDARD SPEC. FOR HIGHWAY BRIDGES SEC. 1-2-12IA) AND (C), 1961 EDITION. 21 Wsc SUPERIMPOS ED (WHEEL] LOAD ON J-M TRANSMISSION PIP E - SINGLE WHEEL = 10,000 LB COVER OVER TOP OF PIPE 2' 2'6" PIPE DIAMETER 18" 20" 21" 24" 27" 30" 33" 36' 1302 1407 1450 1591 1700 1810 1870 1968 964 1051 1080 1212 1307 1410 1480 1569 3' 736 804 834 934 1020 1108 1174 1250 4' 453 500 523 590 650 710 765 826 5' 306 340 356 400 444 490 528 570 6' 220 243 256 290 320 354 382 414 8' 127 140 146 167 187 206 223 244 10' 83 90 96 110 123 137 150 163 12' 57 63 66 73 83 97 106 117 16' 33 37 40 43 47 53 60 67 20' 20 23 25 27 28 33 37 VALUES SHOWN ARE IN LBS/LIN FT OF PIPE NOTE: TABLE IS BASED ON IMPACT FACTOR OF ONE. IF IMPACT IS TO BE USED SIMPLY MULTIPLY VALUE FROM TABLE TIMES DESIRED IMPACT FACTOR. 40 !/3i 22 (m mmm CORRELATION OF BEDDING CONDITIONS AND LOAD FACTORS* lt It B' CLASS A d m.m Concrete cradle, load factor 2.2-3.4 i Bemin | MCW.rAc}5 4 Concrete arch, load factor 2.8-3.4 CLASS B Fine granular fill ' 0.6 Bc ` Shaped bottom with tamped backfill, load factor 1.9 Compacted granular bedding, load factor 1.9 m Shaped bottom, load factor 1.5, not recommended CLASS D Granular bedding, load factor 1.5 Loose backfill Flat bottom, load factor 1.1, impermissible bedding, not recommended *WPCF Manual of Practice No. 9 "Design and Construction of Sanitary and Storm Sewers". 23 f ( ( 24 Water Hammer and Surge--Analysis and Control The slowing down or stopping of any moving mass requires a force or forces to counterbalance the ki netic energy that keeps it in motion. The faster the mass is decelerated and brought to a halt, the greater the force that is required. It is somewhat an oversimplification, but water hammer or surge can be defined in these terms. The shutting of a valve or the stopping of a pump causes a moving column of water in a pipeline to slow down and stop. The forces that bring about this deceleration are exerted radially on the moving water column by the pipeline wails. Conversely the water exerts added pressure on the pipe and the hoop stress in the pipe walls thus increases over the normal operating pressure values. The faster the column of water is brought to a halt, the higher these stresses rise. The pipe wall stresses then are developed by, and increase in direct proportion to, the internal pres sure which builds up as the column of water decel erates. The slower the deceleration, the less the pressure build up and the less the pipe wall stress increases. It is, therefore, of importance to the pipe designer to know how to control the rate of velocity fluctuation and, consequently, the magnitude of pressure variations during transitional periods. By such control he can keep pipe wall stresses during surge to a predetermined value leading to an eco nomical installation. Water, being a liquid, will act in a fairly complex manner when undergoing acceleration or decelera tion. Pressure waves are set up which move along the pipeline at a rate of 2500 to 4500 feet per sec ond depending on pipe wall material. These will continue until they encounter a boundary condition such as a reservoir, a closed valve or change in pipe diameter, and will then reflect back in the opposite direction. The wave motion will oscillate back and forth in the pipe until it is dampened out by friction effects on the pipe walls. The two major causes of water hammer or surge are: 1. The closing or opening fully or partially of a valve in a pipeline system. The valve may be in the line for one of a number of purposes. It could be a gate valve, float valve, pressure re ducing valve, etc. 2. The starting up or shutting down a pump (switch or power failure). It can be seen that both of these occurrences cause changes in the velocity and consequently the quantity of water flowing in the pipeline. Ignoring the effects of surge in the pipeline can lead to difficulties after the line is in operation. Surges can result in damaged equipment and seri ously reduced capacity. WATER HAMMER ANALYSIS The elastic wave theory for surge analysis has been empirically established as correct by many experi ments starting as early as 1890. Its application to pipeline problems will yield results which are accu rate and may be relied upon for adequate analysis. Water hammer pressures are a function of the maximum rate of change of flow. When a valve is closed or a pump stops, a pressure wave is propa gated along a pipeline. The velocity of that wave is the same as the velocity of sound in water modified by physical characteristics of the pipeline and is given by the following equation: 4660 Where: a = Pressure wave velocity (ft/sec) k =s Modulus of compression of water (300,000 psi). d= Internal diameter of pipe in inches E= Modulusof elasticity of A-C pipe (3,400,000 psi) e = Wall thickness in inches 4660 = Velocity of sound in water (ft./sec.) If the pressure wave is reflected back from a boundary condition such as a reservoir and reaches, its initial position after the flow in the line is com pletely stopped, then maximum water hammer pres sure for those conditions will result. Stopping of the flow may be effected by closing a valve or a pump stoppage. The magnitude of that maximum pres sure is given by: h= ay g Where: h = Surge pressure in feet of water V = Velocity of water in the pipeline during normal conditions--ft./sec. a = Velocity of the pressure wave--ft./sec. 25 g = Acceleration due to gravity = 32.2 ft./sec.2 The longest elapsed time before final flow stop page that will still permit this maximum pressure to occur is called the critical time and is simply the total length the pressure wave travels in one cycle divided by the velocity of the wave. It is given by the following equation: Where: U = The critical time, seconds L = Distance within the pipeline that the pressure moves before it is reflected back by a boundary condition--feet a = Velocity of the pressure wave = feet/sec. VALVE CLOSURE A valve in a water line may be of a number of differ ent varieties including gate, cone, and globe valves. In closing a valve, the area of the cross section of the pipeline progressively cut off is not generally proportional to the reduction in flow. Graph 1 pre sents a plot of stem travel vs. flow in the line for three types.of valves. Note that the first 30-40% of stem travel has little effect on the flow in the pipe line. As stated previously water hammer pressure is a function of the maximum rate of change of flow. Therefore, if tangents to the curves on Graph 1 are drawn at the fastest rate of change (or steepest slope), the effective time of closure (TE) is obtained. (See curves on Graph 1 with tangents plotted and valves of TE determined.) This "effective time" is the time that is used in water hammer calculations. It is, in most cases, about one-half of the actual valve closing time. This indicates that if the critical time of a certain valve is calculated from the for mula and found to be X seconds, then the actual time of valve closure for this condition will be ap proximately 2X seconds. This is reprinted from the May 1958 Issue of Consulting Engineer with their permission and that of the Author, Mr. S. Logan Kerr. 26 In the design of a water system one of the major considerations in the selection of a pipe is the "de sign internal pressure" that the pipe will be re quired to carry in service. The "design internal pressure" is the operating pressure plus the water hammer pressure, in order to keep the water ham mer or surge pressures at a controlled level, calcu lations must be made to determine the times of valve closure that will be required to stay within the design pressure level. Graph 2 presents a convenient method for deter mining effective valve closure times for a given per centage of the maximum pressure (surge pressure when valve is closed in less than the critical time). First, determine the pipeline constant K given by: Where: K = Pipeline constant a = Velocity of the pressure wave in the line (ft./sec.) V = Velocity of water in the flow line under normal conditions (ft./sec.) g = Acceleration due to gravity (32.2 ft/sec2) h0 = Operating pressure in the line under normal conditions (ft. of water) Second, determine the maximum head that might be developed from the surge by employing the for mula hmas:=^ Third, determine the percentage of hmnx to be controlled. Enter Graph 2 with the K value plus the percentage h,,,.,* and find the corre sponding effective closing time shown on the hori zontal axis. This is given in units of which rep resents the critical time for the pipeline. Note that the time determined is the "effective" closing time and the actual time of valve stem travel is about twice as long. The reason being is that the first half of the closing of the valve has little effect on the stoppage of the flow, it is the closing of the final half of the valve stem travel which closes off the flow. The second half is the "effective" closing time. Therefore, two times the effective closing time is the actual time of the valve stem travel. PUMPED SYSTEMS In relation to water hammer and surge the most im portant elements in a system are pumps and valves. In a gravity system valves only have'to be consid ered. Both must be considered in a pumped system. The surge analysis of a pumped system is more complex than in a purely gravity system because: a. In a pumped system .the problem begins with the slowing down of the rising water column when the pump is shut off because of power failure or otherwise. Consideration must be given to the time required for the pump to stop and the flow to come to a halt. This in volves the inertia of the motor and any fly wheel in the assembly. In a gravity system the hydraulic problem consists only of stopping the descending water column. b. The pipeline profile is usually irregular with successive high and low points and variable slopes. These conditions may give rise to wa ter column separation causing severe surges and operational troubles. Surges from water column separation do not follow a standard pattern and have been measured at many times the calculated values. The design of a pumped system may involve the consideration of alternative layouts to keep surges and the consequent operational difficulties to a minimum. This work would be directed toward (a) reducing the magnitude of surges and (b) reduce the risk of water column separation that may be caused by the shut down of a pump. Water column separation can be serious due to the large magnitude of the surges developed when the water column rejoins. It can occur: a. At pump locations at start of a steep main. b. When the pressure at a high point falls below atmospheric and air enters the line through air valves that may be located at a high point. c. When the pressure falls to below vapor pres sure of water. Water column separation can cause difficulties not only because of the before-mentioned surges set up by rejoining of the water column, but be cause of the difficulties in getting air out of the lineon subsequent start up even with air valves. En trapped air can cause flow fluctuations and seri ously reduce the capacity of the system. METHODS OF CONTROL The two types of surge to be controlled are negative surge and positive surge. The type is determined, of course, by whether the surge pressures devel oped are below or above the normal static level. Negative surges in themselves are usually not dangerous, except when they cause water column separation. If this occurs extremely high positive surges result when the cavity closes frequently causing serious problems. The control of both neg ative and positive surges should be given consid eration. TYPES OF SURGE CONTROL DEVICES Limiting negative and positive surges. 1. Flywheel on pump motor--ln the event of a power outage the inertia of the flywheel will 27 i1 1 28 keep the pump running for a period of time ` gradually slowing to a stop. This means that the water column in the pipeline will also be brought to a stop gradually reducing the risk of water column separation. 2. Standpipe--This is generally a tank with the surface of the water at atmospheric pressure. It is, therefore, only practical at low heads. At a pump stoppage and consequent reduced pres sure, the reserve of water in the tank flows into the pipe and reduces the risk of water column separation. For positive surge control the tank provides an outlet for the build-up pressure in the system. 3. Air Vessel or Surge Tank--This is an enclosed vessel containing air and water. It functions similar to a standpipe. The major difference is that the air in the vessel is under pressure and much higher heads can be employed in the pipe system. The principle is the same with water re entering the line during negative surge and leaving during positive surge. 4. One way surge tank--This is an adaption of the surge tank that contains a check valve which permits water to enter the line during negative surge but will not permit water to leave during positive surge. It is, therefore, only for control of negative surges and is very effective. 5. Reservoir of Water--This is similar to the one way surge tank, but provides some control of positive surge by permitting the slow entrance of water into the reservoir during a positive surge. 6. Suction Pipe--This is a bypass around the pump from the suction side. It contains a check valve to prevent backflow into the reservoir. It effectively reduces negative pressure adja cent to the pump. 7. Surge relief valve--This is used for controlling positive surges only. The valve opens at a cer tain pressure and discharges water to relieve the surge. They must be carefully designed and controlled to be effective. 8. Non-return valve--A check strategically placed in a line can bring a small measure of relief to positive pressure. However, unless properly placed, it can lead to higher surge rather than lower. 9. Reversal of pump--At pump stoppage the col umn of water reverses itself. If the pump will not run backwards to permit water to flow back through it, positive surges will be developed with a sudden stopping of the backflowing col umn of water. The pump should be designed to run reversed without damage to itself. 10. Controlled valves--This is one of the most ef fective means for controlling positive surges. As explained previously the rate of closing of a valve can be calculated to allow an acceptable level of surge. From an economic standpoint, it is usually very worthwhile to properly evaluate the surge potential in a system under design. The cost of control de vices may be balanced agpinst the added strength of pipe, valves and other equipment if surges are not controlled and the most advantageous conclu sion reached. Manufacturers of surge control equipment or consultants in this field should be sought for ad vice in the complex situations. SURGE CALCULATION EXAMPLE The following example illustrates the calculation that may be followed in the determination of valve closing time for the control of surge within pre scribed limits. A 24" gravity transmission line is to operate at a pressure of 100 psi. Velocity in the line is to be 5 f.p.s. A valve is to be included in the line at a distance of 5,000 feet from the reservoir. If posi tive surge pressure is to be controlled within 50 psi, determine the minimum time for valve closure. As sume that the effective closing time is one-half of the actual valve stem travel time. (E for A-C = 3.4 x 106, wail thickness is 1.5", k for water = 3 x 10s.) 1. Determine surge wave velocity 4660 4660 =3000 ft./sec. 3xl05x24 3.4xl04xl.5 2. Determine maximum surge pressure if the valve closes within the critical time h _ ^ _ 30flP.j 5 _465 ft of water (200 psi) 3. Determine the critical time 2L a " 2 x 5000 3000 = 3.33 sec. 4. Determine Constant "K" for use in Graph 2 aV 3000 x 5 * " 2gh0 " 2 x 32.2 x 231 " 5. Determine percent of maximum surge pressure that should not be exceeded in the system. 50 200 x 100 = 25% 6. Enter Graph 2 with percent of hra,,x (25%). Go horizontally to the curves where K = 1.0. Read the effective closing time along the horizontal axis. This value is 2.6 and is given in units of 2L/a seconds. The effective closing time in sec onds would be 2L/a x 2.6 = 3.33 x 2.6 = 8.7 sec. The actual valve stem travel time would be twice this amount or 17.4 sec. This calculated time (17.4 sec.), therefore, represents the fast est allowable time the valve can be closed in or der to keep the surge pressure below the desired control level of 50 psi. ) !i3i 30 Air in Pipelines Air in pipelines can cause serious operational diffi culties including reduction in capacity because of reduced cross-sectional area and fluctuation in flow caused by expanding and contracting of the air in the line. Serious surges can be set up by these fluc tuations in flow which cause sudden movements of the air from one location to another followed by slugs of water. e. Negative surges--The best way to prevent air from entering under these conditions is to de sign out the possibility of water column sepa ration. Large volumes of air may be involved here and can cause serious problems. Any one of the negative surge control devices de scribed in Appendix F will normally be ade quate. Air can enter a pipeline in many ways including: a. At the intake b. Release of air from water by temperature and pressure variation c. On draining the line d. Draining of parts of the line occurring during normal shut-down e. Negative surges causing air to enter at air valves Air should be prevented from entering the line in the first place. This is very important to reduce op erational difficulties. Suggested solutions for control are as follows: a. Intake--Correct design procedures, provide low water level pump cut-off b. Release of air--Air is entrained in the water at intake and its release cannot be prevented. However, the quantities are not large and pro visions for exhausting can be made by means of air valves. There are various types of air valves with different functions, and the selec tion of the proper type is essential. c. Draining the line--On draining, air, of course, cannot be prevented from entering the line. Large orifice air valves should be provided for exhausting the air during refilling. Refilling does not often occur and, therefore, long fill ing times may be satisfactory. d. Drainage during shut down--This can be a se rious problem. Open standpipes can be pro vided for air entry and exhaust. Sweeping air out using high velocities is also a method. RECOMMENDATIONS TO COMBAT AIR ENTRAPMENT Colorado State University has conducted studies to determine the effect of Air Entrapment in Pipe Lines. The result of the studies proved that sud denly released entrapped air, under apparently static conditions, creates a situation similar to that of classic water hammer. Pressures are generated which may be in the order of 15 times the pipe line test pressure. Any pipe line material is seriously affected by this rapid magnitude of load increase. Hydrostatic failure due to "defective pipe" may in all probability be traced to suddenly released en trapped air. The initial filling and testing of a pipe line is often the most critical period of its service life. Recommendations to combat air entrapment were made as follows: 1. Pipe line should be laid to grade wherever possible. 2. Automatic "continual acting" air release valves should be used at all high points. 3. Air should be bled from pipe line slowly. 4. Limit filling velocity in the pipe line to one foot per second or less. 5. Use d/D = 1/10 to 1/100. d = diameter of air release valve. D = pipe diameter. The results of this study, together with the recom mendations, have been found most useful to contractors in performing pipe line tests. Such recommendations have been found useful also to engineers from the standpoint of designing air out of pipe lines. i1 T f c 32 Combined Loading Curves for Pipe Sizes 18" io 36 DESIGN INTERNAL PRESSURE AND DESIGN EXTERNAL LOAD INTERCEPTS FOR USE WITH SELECTION CURVES T-30 T-35 T-40 T-45 T-50 T-60 T-70 P=300 psi P=350 psi P=400 psi P=450 psi P=500 psi P = 600 psi P=700 psi PIPE W SIZE Ibs/lin ft W Ibs/lin ft WW Ibs/lin ft Ibs/lin ft W Ibs/lin ft WW Ibs/lin ft Ibs/lin ft 18" 2,500 3,000 4,000. 5,000 6,500 8,500 11,000 20" 2,500 3,500 4,500 5,500 7,100 9,500 12,000 21" 2,500 3,500 4,500 5,800 7,300 9,700 12,500 24" 2,800 3,800 5,000 6,200 8,100 11,000 15,000 27" 3,500 4,200 5,500 7,000 8,800 12,500 16,500 30" 3,500 4,500 6,000 7,500 9,700 13,500 18,000 33" 3,500 5,000 6,500 8,000 10,500 14,500 19,500 36" 4,000 5,000 7,000 9,000 11,200 16,000 21,000 w= W -\J or P = P(l-Sf2> Where: P = the internal hydrostatic design pressure for the pipe when no external load exists--psi. W = the external crushing design load for the pipe (3-edge bearing test) when no internal pressure exists --Ibs/ft of pipe. P=the internal hydrostatic pressure for that pipe when an external crushing load (w) is acting simultaneously --psi. w= external crushing load for the pipe when an internal pressure (p) is also acting on the pipe --Ibs/ft of pipe. 33 1 ! 34 I ( 18" TRANSMISSION PIPE # EXTERNAL CRUSH DESIGN LOAD (3-Edge Bearing) - W (Ib/ft) W= (EARTH LOAD + LIVE LOAD) SAFETY FACTOR BEDDING FACTOR 35 20" TRANSMISSION PIPE INTERNAL HYDROSTATIC DESIGN PRESSURE IN psi -- p = (OPERATING PRESSURE + WATER HAMMER) SAFETY FACTOR ( 2,000 4,000 6.0Q0 8,000 10,000 12,000 EXTERNAL CRUSH DESIGN LOAD (3-Edge Bearing) -- W(lb/ft) W= (EARTH LOAD + LIVE LOAD) SAFETY FACTOR BEDDING FACTOR 14,000 16,000 ( 36 21" TRANSMISSION PIPE INTERNAL HYDROSTATIC DESIGN PRESSURE IN psi -- p = (OPERATING PRESSURE + WATER HAMMER) SAFETY FACTOR EXTERNAL CRUSH DESIGN LOAD (3-Edge Bearing) - W(lb/ft) W = (EARTH LOAD + LIVE LOAD) SAFETY FACTOR BEDDING FACTOR 37 24" TRANSMISSION PIPE INTERNAL HYDROSTATIC DESIGN PRESSURE IN psi p = (OPERATING PRESSURE + WATER HAMMER) SAFETY FACTOR- EXTERNAL CRUSH DESIGN LOAD (3-Edge Bearing) - W (Ib/ft) W = (EARTH LOAD + LIVE LOAD) SAFETY FACTOR BEDDING FACTOR 38 f \ i r is i *! 1 i i i i . i r xho* s u* > uuJ. < co S' U5J 2 < X xUHi < $ + UDXJ CuaCXOO.i Z(5 H < X UXi o II a a z UX3i CO CO XLXU zo CUQOi 0 1 CoO X a>- X < z X ui EXTERNAL CRUSH DESIGN LOAD (3*Edge Bearing) -- W(!b/ft) W= (EARTH LOAD + LIVE LOAD) SAFETY FACTOR BEDDING FACTOR 39 INTERNAL HYDROSTATIC DESIGN PRESSURE IN psi -- p ~ (OPERATING PRESSURE -f- WATER HAMMER) SAFETY FACTOR ( EXTERNAL CRUSH DESIGN LOAD (3-Edge Bearing) -- W (Ib/ft) ( W = (EARTH LOAD + LIVE LOAD) SAFETY FACTOR BEDDING FACTOR 40 > Illustrative Problems on Pipe Selection PROBLEM 1 A 24" TRANSITE transmission line is to be installed in a 4 ft. wide trench with 5 feet of cover. The oper ating pressure will be 100 psi. Surge pressures will be limited to a maximum of 50 psi. A 10,000 lb wheel load is to be assumed with impact factor = 1. Class C bedding will be used. Select the proper strength of pipe to be used with a safety factor of 2.0 in hydro (OP + WH) and 1.5 in crush (EL + LL). PROBLEM 2 Assume the same conditions as in Problem 1, but use safety factors of 2.5 in hydro (OP + WH) and 2.0 in crush (EL + LL). Solution: Follow instructions for use of selection charts with safety factors as selected by the designer. 1. OP + WH = 100 + 50 = 150 psi Solution: Following instructions for use of selection charts with safety factors as suggested by J-M: 1. OP + WH = 100 + 50 = 150 psi 2. EL + LL = 2030 + 400=2430 Ibs/ft (From ta bles in appendices C & D) 3. (OP + WH) (SF) = 150 x 2.0 = 300 psi 4. (EL + bp' ---- = --yl1 `5~ = 2430 Ibs/lin ft. 2. EL + LL = 2030 + 400 = 2430lbs/ft. 3. (OP + WH) (SF) = 150 x 2.5 = 375 psi . (EL + LL) (SF) 2430x2.0 4. ---- p---------- =------ ----------= 3250 5. Enter combined loading chart for 24" pipe, using left hand and bottom scales. Plot as one point the two values from steps 3 and 4. The point falls between T-40 and T-50. Use T-50. 5. Enter combined loading chart for 24" pipe, using the left hand and bottom scales. Plot the two loads as a single point on the chart. The point falls between T-40 and T-50. Use T-50. PROBLEMS 41 i ( 42 Pipe and Coupling Dimensions and Weights PIPE AND COUPLING DIMENSIONS (INCHES) PIPE SIZE 18" 20" 21" 24" 27" 30" 33" 36" D 18.00 20.00 21.00 24.00 27.00 30.00 33.00 36.00 d2 19.28 21.44 22.52 25.76 29.00 32.24 35.48 38.72 d3 19.44 21.60 22.68 25.92 29.16 32.40 35.64 38.88 T-30 d6 . 20.16 22.32 23.40 26.64 29.88 33.12 36.36 39.60. d7 21.76 24.14 25.34 28.90 32.50 36.10 39.68 43.24 Dg 19.41 21.57 22.65 25.89 29.13 32.37 35.61 38.85 PIPE SIZE 18" 20" 21" 24" 27" 30" 33" 36" D 18.00 20.00 21.00 24.00 27.00 30.00 33.00 36.00 d2 19.28 21.44 22.52 25.76 29.00 32.24 35.48 38.72 d3 19.44 21.60 22.68 25.92 29.16 32.40 35.64 38.88 T-35 d6 20.16 22.32 23.40 26.64 29.88 33.12 36.36 39.60. 07 21.76 24.14 25.34 28.90 32.50 36.10 39.68 43.24 Dg 19.41 21.57 22.65 25.89 29.13 32.37 35.61 38.85 PIPE SIZE 18" 20" 21" 24" 27" 30" 33" 36" D 18.00 20.00 21.00 24.00 27.00 30.00 33.00 36.00 PIPE SIZE 18" 20" 21" 24" 27" 30" 33" 36" D 18.00 20.00 21.00 24.00 27.00 30.00 33.00 36.00 d2 19.90 22.12 23.28 26.48 29.90 33.12 36.52 39.78 Dz 19.90 22.12 23.28 26.48 29.90 33.12 36.52 39.78 d3 20.06 22.28 23.44 26.64 30.06 33.28 36.68 39.94 d3 20.06 22.28 23.44 26.64 30.06 *33.28 36.68 39.94 T-40 d6 20.78 23.00 24.16 27.36 30.78 34.00 37.40 40.66 T-45 d4 20.78 23.00 24.16 27.36 30.78 34.00 37.40 40.66 D? 22.96 25.46 26.76 30.36 34.30 37.92 41.76 45.44 D, 22.96 25.46 26.76 30.36 34.30 37.92 41.76 45.44 Dg 20.03 22.25 23.41 26.61 30.03 33.25 36.65 39.91 D, 20.03 22.25 23.41 26.61 30.03 33.25 36.65 39.91 SUBJECT TO MANUFACTURING TOLERANCE. d9* 19.70 21.86 22.94 26.18 29.43 32.67 35.92 39.16 N 10.00 10.00 10.00 10.00 11.00 11.00 11.00 11.00 Ds>* 19.82 22.05 23.09 26.31 29.57 32.83 36.10 39.36 N 10.00 10.00 10.00 10.00 11.00 11.00 11.00 11.00 d9* 20.30 22.52 23.68 26.88 30.30 33.54 36.92 40.18 D,* 20.30 22.52 23.68 26.88 30.30 33.54 36.92 40.22 N 10.00 10.00 10.00 10.00 11.00 11.00 11.00 11.00 N 10.00 10.00 10.00 10.00 11.00 11.00 11.00 11.00 PIPE AND COUPLING DIMENSIONS (INCHES) PIPE SIZE 18" 20" 21" 24" 27" 30" 33" 36" D 18.00 20.00 21.00 24.00 27.00 30.00 33.00 36.00 Dj 19.90 22.12 23.28 26.48 29.90 33.12 36.52 39.78 D, 20.06 22.28 23.44 26.64 30.06 33.28 36.68 39.94 T-50 D, 20.78 23.00 24.16 27.36 30.78 34.00 37.40 40.66 D, 22.96 25.46 26.76 30.36 34.30 37.92 41.76 45.44 D, 20.03 22.25 23.41 26.61 30.03 33.25 36.65 39.91 PIPE SIZE 18" 20" 21" 24" 27" 30" 33" 36" D 18.00 20.00 21.00 24.00 27.00 30.00 33.00 36.00 D, 20.50 22.83 23.96 27.42 30.89 34.35 37.74 41.22 d3 20.66 22.99 24.12 27.58 31.05 34.51 37.90 41.38 T-60 D, 21.38 ' 23.71 24.84 28.30 31.77 35.23 38.62 42.10 D, 24.36 26.99 28.34 32.32 36.39 40.39 44.28 48.40 D. 20.63 22.96 24.09 27.55 31.02 34.48 37.87 41.35 PIPE SIZE 18" 20" 21" 24" 27" 30" 33" 36" D 18.00 20.00 ' 21.00 24.00 27.00 ' 30.00 33.00 36.00 d2 20.94 23.28 24.38 27.96 31.44 - 35.00 38.46 42.04 Dj 21.10 23.44 24.54 28.12 31.60 35.16 38.62 42.20 T-70 d6 21.82 24.16 25.26 28.84 32.32 35.88 39.34 42.92 d7 25.50 28.26 29.56 33.78 38.02 42.24 46.32 50.56 D, 21.07 23.41 24.51 28.09 31.57 35.13 38.59 42.17 `SUBJECT TO MANUFACTURING TOLERANCE D,* 20.35 22.58 23.71 27.07 30.46 33.84 37.22 40.61 D,* 20.81 23.18 24.27 27.74 31.21 34.68 38.15 41.61 . D,* 21.32 23.69 24.88 28.43 31.99 35.54 39.09 42.65 N 10.00 10.00 10.00 10.00 11.00 11.00 11.00 11.00 N 10.00 10.00 10.00 10.00 11.00 11.00 11.00 11.00 N 10.00 10.00 10.00 10.00 11.00 11.00 11.00 11.00 PIPE SIZE 18" 20" 21" 24" 27" 30" 33" 36" WEIGHTS--LBS/FT (INCLUDING COUPLINGS) T-30 46.9 56.9 62.3 79.9 100.8 123.1 147.9 174.4 T-35 49.9 62.1 66.6 84.1 105.9 129.5 155.8 184.0 T-40 64.0 77.8 86.8 106.6 138.3 164.7 200.5 233.2 T-45 64.0 77.8 87.6 106,6 138.3 164.7 200.5 235.6 T-50 65.3 79.5 86.6 112.9 144.3 177.1 214.1 254.5 T-60 79.8 99.9 108.0 140.8 180.0 221.9 267.8 318.5 T-70 95.5 117.7 129.5 168.9 215.5 264.8 320.5 381.8 44 System Specifications MATERIAL SPECIFICATION TRANSITE TRANSMISSION PIPE a. General Asbestos-cement pipe shall be "T" pipe as manu factured by Johns-Manville. This pipe shall be manufactured and tested within the continental limits of the United States in accordance with the requirements of this specification. The pipe denoted on the drawings and in the schedule of symbols has a corresponding classifi cation in the following selection table. This classi fication establishes the minimum requirements for pipe to be used in the locations shown on the drawings. b. Classification Various classifications of asbestos-cement pipe are permitted to be used at certain locations, and are designated T-30, T-35, T-40, T-45, T-50 and T-60. c. Basis of Acceptance The acceptability of the pipe will be based on the results of the following tests performed by the manufacturer: hydrostatic routine, hydrostatic lot, crushing strength, and by inspection during or after manufacture. Certification that the pipe meets the test require ments of these specifications may be required. d. Materials The asbestos-cement pipe shall be composed of an intimate mixture of Portland cement, silica, and as bestos fiber, and water, free from organic sub stances, with or without the addition of curing agents, and cured in such manner as will produce pipe meeting the requirements of these specifica tions. e. Fabrication The pipe shall be formed under pressure and thor oughly autoclaved. f. Dimensions 1. SIZES. -- The pipe may be furnished in sizes (internal diameter): 18, 20, 21, 24, 27, 30, 33, and 36 inches. 2. DIAMETER TOLERANCE.-- The average internal diameter, measured 3 inches from the end of the pipe, shall not vary from the manufacturer's standard, as approved, by more than 5 percent. 3. WALL THICKNESS. -- The wall thickness at the machined portions of any pipe shall not be less than the manufacturer's standard as follows: Size of Pipe 18" 20"-24" 27"-30" 33"-36" Wall Thickness Tolerance .12" .14" .17" .20" 4. STRAIGHTNESS. -- No pipe shall have a vari ance from straightness, measured as an outside middle ordinate, of more than 0.05 inches per foot of length. g. Workmanship and Finish The pipe shall be uniform in quality and shall be free from bulges, dents, fractures, and tears on the inside surface which result in a variation in diam eter greater than 0.20 inch from that obtained on adjacent unaffected portions of the surface. The pipe shall also be free from excessive interior sur face flaking and roughness. The machined ends of the pipe shall be free from dents and gouges which will affect the tightness of the joint. h. Joints The asbestos-cement pipe joint shall consist of two pipe spigots coupled with a collar and two rubber rings. The couplings shall be designed to permit joint flexibility and shall be grooved to re ceive the rubber rings and hold them in proper po sition. The spigot end shall be step machined to close tolerance to provide the proper pressure on the rubber ring and shall have a shoulder to auto matically position the pipe in the coupling to leave sufficient space for the pipe to expand upon wet ting and for maintaining end clearance when de flected as outlined in the installation specification. The rubber ring shall be of uniform solid cross- section and shall conform to the latest revision of ASTM Specification D-1869 entitled "Rubber Rings for Asbestos-Cement Pipe." 45 ' i. Routine Hydrostatic Test Each pipe unit and each coupling shall withstand routine hydrostatic test load of not less than the pressure designated in the table shown. The routine hydrostatic test shall be conducted by placing the pipe in a hydrostatic pressure test ing machine with gaskets which seal the ends of the pipe. Couplings may be tested with the pipe as described above or standard couplings may be tested with a rubber bladder inside of the coupling and, if so tested, each coupling shall have suffi cient strength to withstand a hydrostatic test of one and one-half times the head designated in the table shown, or 800 lbs., whichever is lower. Rou tine hydrostatic tests will not be required on A/C tapers or heavy tapped couplings and all such fit tings will be manufactured of the same material and by the same method as used in manufacturing the pipe that is tested. j. Lot Hydrostatic Test One 1-foot unmachined section or longer out of every lot of 300 shall withstand a hydrostatic test of not less than the pressure designated in the table shown. Tests will be performed as described in the previous section (i). In the event that a test specimen fails to with stand the lot hydrostatic test, the manufacturer will be allowed to test two additional specimens of the same size and class manufactured during the same shift. If either of the two additional specimens fail to pass the test, the entire lot of pipe represented by the test specimen shall be rejected. k. Crushing Strength Test One-foot lengths of pipe cut from unmachined por tions of the pipe shall withstand the minimum crushing strength prescribed below. A 12-inch long test specimen shall be cut from a standard pipe unit selected from each 300 lengths of each size and classification of pipe and tested in accord ance with ASTM Specification C-500. In the event that a test specimen fails to with stand the crushing strength test the manufacturer will be allowed to test two additional specimens of the same size and class manufactured during the same shift. If either of the two additional specimens fail to pass the test, the entire lot of pipe repre sented by the test specimen shall be rejected. l. Chemical Stability To assure chemical stability, the pipe shall not have an uncombined calcium hydroxide content in ex cess of 1% when tested in accordance with the method outlined in ASTM Specification C-500. m. Marking Each standard and random length of pipe shall be marked with the size and classification of pipe, name of manufacturer or trademark, and the date of manufacture. ALL SIZES ROUTINE HYDROSTATIC TEST LOADS (PSI) T-30 T-35 T-40 T-45 T-50 T-60 225 263 300 338 375 450 T-70 525 ALL SIZES LOT HYDROSTATIC TEST LOADS (PSI) T-30 T-35 T-40 T-45 T-50 300 350 400 450 500 T-60 600 T-70 700 PIPE SIZES 18" 20" 21" 24" 27" 30" 33" 36" CRUSHING TEST LOADS (LBS/LIN FT) T-30 2500 2500 2500 2800 3500 3500 3500 4000 T-35 3000 3500 3500 3800 4200 4500 5000 5000 T-40 4000 4500 4500 5000 5500 6000 6500 7000 T-45 5000 5500 5800 6200 7000 7500 8000 9000 T-50 6500 7100 7300 8100 8800 9700 10500 11200 T-60 8500 9500 9700 11000 12500 13500 14500 16000 T-70 11000 12000 12500 15000 16500 18000 19500 21000 INSTALLATION SPECIFICATIONS TRANSITE TRANSMISSION PIPE a. Installing All asbestos cement pipe shall be laid in accord ance with AWWA specification C603 with the fol lowing additions and clarifications: Asbestos cement pipe, including fittings, shall be laid to the lines and grades shown in the draw ings. Departure and return to established align ment and grade shall not exceed 1/16 inch per foot with a total of not more than one inch depar ture. The joining of pipe sections shall be such as to produce water tight lines for the conveyance of water. In all cases every field joint shall be checked with a feeler gauge for proper ring posi tion. The pipe trenches shall be kept free of water which might impair pipe joining operations. The methods of lowering the pipe into the trench and placing in position shall be such as to prevent getting dirt inside of the pipe and coupling and to prevent damage to the pipe. Before and during as sembly of the joint all parts shall be clean and shall be free of mud, ice, oil, or grease. The use of non-toxic water-soluble lubricant will.be permitted for making the joint assembly. In positioning the pipe, the pipe shall be aligned straight, with ends squared, and the joint closed to properly position the gasket. The pipe shall be maintained firmly in final position. The pipe shall be laid in a trench conforming to the Contract Drawings and Specifications. In all bedding conditions, care shall be taken, so that coupling sleeves will not come in contact with the trench subgrade. The compaction of the backfill shall be as di rected by the engineer. Tamping or flooding may be accomplished as approved by the engineer. b. Curves and Bends Changes in alignment and grade shall be made by deflecting the pipe units at joints. Pipe units shorter than standard length may be required. The maximum deflection angle between adjacent pipe units in place shall not exceed 3V2J for 18" through 24" diameter size and 3' for 30" diam eter and larger sizes. These deflections apply to couplings belled on the job site. For factory belled couplings, use Vz of the above deflections. The ends of each pipe unit shall be laid on the theoretical centerline of the pipeline and to the grade shown on the drawings. c. Testing All piping shall be subjected to a hydrostatic pressure test. Prior to testing, each section of asbestos cement pipe shall be partially backfilled to prevent movement. The test pressure shall be the operating pres sure plus 50 psi, or the total of the operating pressure plus surge allowance, whichever is greater, as defined by the engineer. Tests on asbestos cement pipe shall not be ap plied until the main has been filled with water for a minimum of twenty four hours. This test shall be performed on ail sections of the water main so that all pipe, valves, fittings, fire hydrants, connections and water services are subject to the test. The test pressure shall be maintained continuously by pumping for a period of at least one hour. At the end of the first hour the pressure shall meet the requirements stated above. Pumping shall then be discontinued for one hour and the drop in pressure read on the dial of the gauge at the end of the second hour and recorded. The initial test pressure shall then be restored by pumping and the quantity of water pumped into the line to accomplish this shall be measured accurately. This quantity shall not ex ceed the amount shown in the table on the next page. If there is any sign of failure at any pointon the line during the test, the test shall be dis continued until the same has been repaired, after which the test shall be repeated until the section tested shall have met the above requirements. The test shall be performed and accepted only in the presence of the engineer or his designated representative. The contractor shall furnish and install, at his own expense, all corporation stops, temporary pipe, fittings, connections, equipment, bulkheads and bracing required for the tests, and he shall be responsible for any and all damages resulting from failure under test of material furnished and installed by him or from faulty workmanship, negligence or improper test methods. 47 PIPE SIZE 18" 20" 24" 30" 36" DISPLACEMENT ALLOWANCE* --Gallons Per 100 Couplings Per Hour TEST PRESSURE (PSI) 50 75 100 125 150 200 225 3.18 3.87 4.52 5.02 5.52 6.37 6.75 3.54 4.30 5.00 5.58 6.12 7.08 7.51 4.24 5.16 6.00 6.69 7.34 8.50 9.01 5.30 6.45 7.51 8.37 9.18 10.62 11.26 6.37 7.75 9.01 10.07 11.02 12.74 13.50 'Evaluated on basis of 150 psi, this is approximately equal to 30 U. S. gallons, per 24 hours, per mile of pipe, per inch of pipe diameter for pipe in 13*foot lengths. To determine total loss for a given length of pipe line;-- against pipe size and under test pressure, find gallons per 100 couplings par hour. Multiply this by actual number oF couplings (each fitting bell equals one half coupling) and then by hours of test duration: For example, one mile of 20" pipe at 150 lbs. for 2 hours -- 6.12 gals, per 100 coup lings per hour. Since there are about 407 couplings per mile, multiply 6.12 by 4.07 giving 24.91 gals, per hour, times 2 = 49.82 gals, allowable leakage in 2 hours. 48 M9H 1 r# Thrust Control Requirements for thrust control are normally in dicated by the engineer. Location, size and type are his responsibility and should be included in his specifications. When Used Thrust control is necessary wherever the pipeline -- changes direction, as at tees and bends; changes sizes, as at reducers; stops, as at a dead end; or is expected to develop thrusts at valves. Size and Type The size and type of thrust control depends on pressure, pipe size, kind of soil and the type of fitting. Following are sketches of a few methods used to control thrust. They are offered as suggestions only. The actual design of thrust control is nor mally the responsibility of the engineer. In un usual conditions consult a soils engineer for economical thrust control designs. ea I TYPICAL THRUST BLOCK -- TEE :as 7r/.; H.V. r? *\- fig * 49 4a 1 j Valve Anchor in Vault t - 51 Valve Anchor Vj cd: > REINFORCED CONCRETE WALL KEYED INTO BANK PLAN ELEVATION 52 < Thrust Piling PLAN n.. ' ms Friction Slab i < 54 Reducers and Adaptors Johns-Manville makes available a number of asbestos-cement accessories for use with TRANSITE Transmission Pipe. with a 2" bushed outlet. The outlet is available with galvanized or brass, with an iron pipe thread only. a. Reducers When connecting one size of pipe with the next lower size pipe, a reducer is required. The reducer is designed so that the outside fits into the coupling of the larger size. The end of the lower size pipe fits into the reducer. The reducer is tapered so that the flow is directed from the larger to the smaller pipe. b. Classification to Classification Adaptor For the same size pipe, where is it necessary to connect two different classifications of pipe in a run and where the end machining is not the same, an adaptor is required. One end is ma chined to receive the coupling of the lower classification pipe and the other end is ma chined to receive the higher classification pipe. c. Heavy Bushed Couplings For each size pipe, a thick wall coupling is available d. C.l. Mechanical Joint Adaptor When connecting TRANSITE pipe to C.l. M.J. fittings, an adaptor is required. One end of the adaptor is C.l. O.D.; the other end is "T" Pipe dimension (D2). The I.D. of M.J. adaptor will be somewhat less than the pipe I.D. M.J. adaptors for butterfly valves must be bevelled on the I.D. at the M.J. end. e. Short Lengths Short lengths (6'-6" long) are available machined each end (MEE) and also machined over-all (MOA). In some sizes and classes the MOA pieces will have a reduced I.D. For making closures the MOA piece is cut to length and two couplings are pushed onto the ends. Next the MOA is dropped into position. Each coupling is then pulled back and centered over the joint. c. Heavy Bushed Coupling (2" 1PT Outlet) d. C.l. Mechanical Joint Adaptor 55 mmmm is Technical Advice Any technical advice which appears in any JohnsManville literature or which is furnished by a Johns-Manville representative with reference to the use of Johns-Manville products is furnished gratis. It is solely for evaluation by the purchaser for use or non-use as the purchaser sees fit. Johns-Manville assumes no obligation or liability for such advice or any results obtained. The physical (or chemical) properties of Johns-Manville TRANSITE Transmission Pipe and Fittings represent typical, average values obtained in accordance with accepted test methods and are subject to normal manufacturing variations. The indicated minimum values are as shown. This information is supplied as a technical service and is subject to change without notice. Check the Johns-Manville Customer Service Center or Local Representative to assure current information. Warranty & Warrant Limitations All products sold are subject to the following warranty: J-M warrants for a period of one year from date of delivery to the original retail purchaser that the Product is free from defects in materials and work manship. J-M MAKES NO OTHER REPRESENTATION OR WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, IN FACT OR IN LAW, INCLUDING WITHOUT LIMITATION, THE WARRANTY OF MERCHANT ABILITY OR THE WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE. The limit of J-M's liability for failure of its Product to meet the foregoing warranty shall be, at J-M's sole option, repair or replace ment of the defective Product and shall exclude any damage caused by accident, misuse, or abuse of the Product. IN NO EVENT SHALL J-M BE LIABLE FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES. For Information on other i-M Products and Systems call Product Information Center at (303) 770-1000 Ext. 2745 57 References "AWWA Standard for Asbestos-Cement Transmis sion Pipe, 18 in. through 42 in., for Water and Other Liquids," AWWA C402. "Standard Practice for the Selection of AsbestosCement Water Pipe," AWWA C401. "TRANSITE Transmission Pipe Installation Guide," Johns-Manville Corp., 1971. WPCF "Design and Construction of Sanitary and Storm Sewers," Manual of Practice No. 9 (ASCE Manuals and Reports on Engineering Practice No. 37), Water Pollution Control Federation, Washing ton, D.C.(1969) Schlick, W. J., "Supporting Strengths for Cast Iron Pipe for Water & Gas Service," Iowa State College Eng. Sta. Bull. No. 146 (June 1940) "Standard Specification for Highway Bridges," American Association of State Highway Officials (AASHO) S. Logan Kerr, "Water Hammer--A Problem In En gineering Design," Consulting Engineer, 5/58 Kolp, D. A. "Water Hammer Generated by Air Re lease" Colorado State University Thesis (August 1968) Albertson, M. L. and Andrews, J. S. "Transients Caused by Air Release," Colorado State Univer sity, August 1970. Marston, Anson, "The Theory of External Loads on Closed Conduits in the Light of Latest Experi ments," Iowa State College Eng. Exp. Sta. Bull. #96 (1930) Webb, T. H., A.S.T.C., A.M.I.E., Australia, Dip. D'Etude (France), "Water Hammer Analysis and Methods of Surge Control" (unpublished) "Standard Specification for Asbestos-Cement Transmission Pipe," ASTM Designation C668. "Standard Methods of Testing Asbestos-Cement Pipe," ASTM Designation C500. \ *->-*->:.. -*-o^ ga*;*?-"** --^as*^v^.n^j^5S7Z>t ^'',i^^^v~pJt-fGjttsr'r^KrxR4s*6'WW **s^pS5^ra^*i-vrjtr5Kar ". ^^`yr'?<?-,'?^~'.`^'*^<2S- iwv'5'vrwr. > ,, '.,*. -T^ ,i. vtc^jy- -nr--.j-"v*..: ;-^ *"-'rv>h:-*'iv-v>7: * "x^ 'jf*' *&rr. * vkv^ *c . -'- -.- .; r '~ '' . ^*>'" : -- . " ^ *"_ .: ;" - - -1' - >r 5jJc '.'.-.' *.v~. *' rw-' v;-i -*.7?.;.. . ^.; -.-, j; -*V. . - ' r\* ''` ^ *. .-. ?7> ,-,V r