line sizing calculation pdf

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January 22, 2019

From point B, draw a vertical line to the steam velocity of 25 m/s (Point C). 8$ "~ DU 5S5"1#\oWUT}6r;)R{Z@U*T6 sk!Ymj\~mvb#nY%_mw1f&Cti Ud?Q2^j65x[F!YqyUBQOH{kF\< /8oWCTmC*9\`nAU(phg\6}>lv*s_/SJ .#Ef0zJv Readers in some parts of the world may recognise the DArcy equation in a slightly different form, as shown in Equation 10.2.2. 40 m/s should be considered a practical limit, as above this, noise and erosion will take place particularly if the steam is wet. Any non-insulated parts of the 80 mm pipe would lose 50% more heat than the 50 mm pipe, due to the extra heat transfer surface area. IF NOT REPEAT THE PROCESS. AS PER ANSI B31.4 Nominal Wall thickness, tn = t + A Where, t Pressure design wall thickness (mm) t = PiD / 2S S Applicable allowable stress value, psi S= 0.72 x E x Specified minimum yield strength of the pipe, psi A Sum of allowances for threading and grooving, corrosion AS PER ANSI B31.8 Nominal Wall thickness, t = (P x D) / 2xSx E x T Where, S Specified minimum yield strength, psi F Design factor E Longitudinal joint factor T Temperature derating factor PIPE SIZE & PRESSURE DROP CALCULATIONS Sheet 10 OF 17 VALUE OF COEFFICIENT Y IN VARIOUS CODES As per IBR, 1977, Regulation 350 Y = 0.5 As per BS 806, 1980 Y = 0.5 As per DIN 2413, 1972 Y = 0 for T < 1200C = (1-E/2) for T >/= 1200C where T is the design temperature As per ANSI B31.1, 1977 & As per ANSI B31.3, 1977 Y is a function of temperature and has following values: Temperature (0C) Ferritic Steels Austenitic Steels 482 510 538 566 593 621 0.4 0.5 0.7 0.7 0.7 0.7 0.4 0.4 0.4 0.4 0.5 0.7 WELD JOINT EFFICIENCY, E IN VARIOUS CODES As per IBR, 1977, Regulation 350 E = 1 for seamless ERW steel pipes = 0.9 for Welded Steel pipes for thickness thickness 29mm PIPE SIZE & PRESSURE DROP CALCULATIONS Sheet 11 OF 17 As per ANSI B31.1, 1977 Seamless pipe = 1.0 Single or double butt-welded pipe with 100% radiography = 1.0 Double Butt-welded pipe = 0.9 ERW pipe = 0.85 Single butt-welded pipe = 0.80 Special Welded pipe ASTM A 211 = 0.75 Furnace Butt-welded pipe = 0.6 As per BS806, 1980 E = 1.0 for seamless, ERW and pipes complying with the requirements of BS3601, BS3602: Part 1 and BS 3604 = 1.0 for Submerged arc welded pipes complying with the requirements of BS3602, Part 2, test category-1(100% NDT for welds) = 0.95 for submerged Arc welded pipes complying with the requirements of BS3602: Part 2, test category-2. revision date: PIPE SIZE & PRESSURE DROP CALCULATIONS Sheet 1 OF 17 INTRODUCTION FOR DESIGNING ANY PIPE SYSTEM, THE FIRST ACTIVITY, AFTER FINALISATION OF PROCESS FLOW DIAGRAM, IS DETERMINING THE SIZE OF THE PIPELINES OF VARIOUS FLUIDS. \Omn=|tey 4$i51?{3{aWt9x4p`Ot!-k~*g{5nA[tO? X>3+?~ne4i7!(7|-X_\lyLwc3^N+toK y:|2OgT#@l aBtY= ,GI_hI"CpLW]gAu The following information is required, and the procedure used for the calculation is outlinedbelow. Z= K1 + K2 K1 = For 90 degree elbow = 30ft K2 = for 45 degree elbow = 16ft Z= (30 x 0.02 x 12) + (16 x 0.02 x 2) Z= 7.84 Therefore Pressure drop, P = (21.55 x 402 / 2 x 9.8) ((0.02 x 95)/0.248) + 7.84) P = 27269.617 Kg/m2 P = 2.73 Kg/cm2 Sheet 16 OF 17 PIPE SIZE & PRESSURE DROP CALCULATIONS CASE-1 NB=200 Sheet 17 OF 17 CASE-2 NB=250 Pressure drop = 4.79 Kg/cm2 Pressure drop=2.73 Kg/cm2 Steam Velocity = 50 m/s Steam Velocity = 40 m/s PRESSURE DROP FROM NOMOGRAPHS: Pressure drop in liquid lines (for both laminar and turbulent condition) can also be found out from the nomographs. Equation 10.2.10 Pressure drop forumla 2(Maximum pipe length: 200 metres). GF(R/ 4Oe2=8+-v7[/yBcwSp}&#Z. The following information isrequired. This tutorial offers detailed advice on standards, schedules, materials and sizing for various saturated and superheated steam duties. 0Xv+Hn4ANyA&e~EHnkz/n=zHL`l7N/?{7a:N>.,\ Air Venting Heat Losses and a Summary of Various Pipe Related Standards, Previous - Introduction to Steam Distribution. H\UtW9o$wn\ RHI%7B$AbGkc-RVG/izxRvE/j~ks9ACr3Fc|&q~13zMBf1pV+U ! VGS The selection of piping material and the wall thickness required for a particular installation is stipulated in standards such as EN 45510 and ASME31.1. The pipe size based on velocity (use Figure 10.2.10). 2 0 obj The objective of any fluid distribution system is to supply the fluid at the correct pressure to the point of use. In the United Kingdom, piping to EN 10255, (steel tubes and tubulars suitable for screwing to BS 21 threads) is also used in applications where the pipe is screwed rather than flanged. Consequently there is no chance of pipe erosion due to suspended water droplets, and steam velocities can be as high as 50 to 70 m/s if the pressure drop permits this. Since the Wall thickness is 11.97 mm which is not a standard wall thickness, we can go for the next standard value i.e) 12.70 mm. Forexample: Only Schedules 40 and 80 cover the full range from 15 mm up to 600 mm nominal sizes and are the most commonly used schedule for steam pipe installations. (Refer attachment 2 for standard wall thickness) PIPE SIZE & PRESSURE DROP CALCULATIONS Sheet 8 OF 17 Thickness = 10.31mm Schedule 60 OD = 219.1mm ID = 198.48 mm. Using the data from Example 10.2.2, determine the pipe size using the nomogram shown in Figure 10.2.7. Conversely, at high line pressures, higher velocities should be acceptable. 0000003046 00000 n Also, it is bad practice to size any pipe up to the limit of its capacity, and it is important to have some leeway to allow for the inevitable future changes indesign. Select lower values of velocities for smaller pipes. PIPE SIZE & PRESSURE DROP CALCULATIONS Sheet 15 OF 17 Calculation of Wall thickness Minimum wall Thickness, t = (72.7 x 273.1) / 2 (1055 + 72.7 x 0.7) = 8.98 mm. Blue Band, being medium grade, is commonly used for air distribution systems, although it is sometimes used for low-pressure steam systems. SOFCON-STANLEY APPROVED Superheated steam can be considered as a dry gas and therefore carries no moisture. The same material may be used for condensate lines, although copper tubing is preferred in someindustries. From Point C, project a horizontal line to the left until it intersects the pressure loss bar/100 m scale (Point D). The inside pipe diameter scale recommends a pipe with an inside diameter of about 120 mm. hb```*|cb`NLLNP sfzPXAgoc;c Ad$::;8:@CGc%(A(f`eewl0!ydc,` vi) Steam lines in intermittent service can be designed with relatively higher velocities since higher noise levels can be tolerated for short durations. (g`\r]!iF R0 z%@ will be more expensive than necessary. From the USA/AUS Moody chart (Figure10.2.5), Where: kS/D = 0.000 3 Re = 93 585 Friction factor (f)=0.02. x]s~}Klk;iJ-+'{:YN\@ ^zvf7v3ku\On%~|jPw/3>>V_sJ;gt=Def\z`e!-C2_`6+^2!~;5x5LAxO2zv^CI*(}"@TI1i Q/P^Z b0Pj|~/wBevP" 'IB&"eiS32"vu* F)^O(F3p2u%.U_A42E[Ih*)"AV_vQUe~i(* rr0S E?ZAJqETr=\\J[`xe R3#4dB A9^E(QG4ek39E# 3 0 obj From point A, project a horizontal line to the right until it intersects the steam mass flowrate scale of 30 000 kg/h (30 t/h) (Point B). hbbd``b`$Z-` $. A pipe with a bore of 130 mm is required; the nearest commercially available size, 150 mm, would be selected. * Since the energy dissipation is associated with shear stress at the pipe wall, the nature of the wall surface will be influential, as a smooth surface will interact with the fluid in a different way than a roughsurface. Even these velocities can be high in terms of their effect on pressure drop. 0000002445 00000 n endstream endobj startxref (Refer attachment 6A & 6B- taken from the CRANE handbook). 0000002716 00000 n The loss in the total energy of fluid flowing through a circular pipe must dependon: u = The mean velocity of the fluid flow(m/s), = The dynamic viscosity of the fluid (kg/m s =Pas), italic-p - body text.jpg= The fluid density(kg/m). 160. Many textbooks simply do not indicate which friction factors are defined, and a judgement must sometimes be based on the magnitudes quoted. Most Active Topics 4WTac#u ;=I,ilWT@j{YwZ>5|S~qAk -=t1I;9=[;>{33Q_NQK^V(X.%+G+NT P~KrlGN5Vb;mhW 6Z"X]c{.4o WY?HuA.?7.S3Wn,rD]J?'tk"|>,ow++nrR}UTNiS {9F" !TREF*`WTf({hxREN\Ld A19E5 jDd?=Nu =c eJfp $; K_a { 0000046174 00000 n Doc Ref.No. In practice whether for water pipes or steam pipes, a balance is drawn between pipe size and pressureloss. Use of high velocity would keep pipe sizes down and minimize flexibility problems. From the knowledge gained at the beginning of this Module, and particularly the notes regarding the DArcy equation (Equation 10.2.1), it is acknowledged that velocity is an important factor in sizing pipes. Information required to calculate the required pipesize: A process requires 5 000 kg/h of dry saturated steam at 7 bar g. For the flow velocity not to exceed 25 m/s, determine the pipe size. Using the information from Example 10.2.4, use Figure 10.2.8 to determine the minimum acceptable pipesize. 1) Pressure Drop: a) The calculated pipeline pressure drop should be within the system permissible limits. %PDF-1.4 Looking for Spirax Sarco products andservices? Pipes for steam systems are commonly manufactured from carbon steel to ASME B 16.9 A106. "x2A(L`P04ZffFK4yGrJ02pPAAq"L \ The heat lost by the insulated pipework was some 21% higher from the 80 mm pipeline than it would have been from the 50 mm pipework. ,Pw o8M8XZ'7OHa1A[UICi%0|9iRM{MY,4l*#BwAK="f\2 ,gXCbi=ItMHx#5iCNhjw3Rb9gflL AS PER ANSI B31.3 For Straight Pipes, Minimum wall Thickness, t = PD / 2 (SE + PY) Required Wall thickness, t = (t + Corrosion allowance) / Mill tolerance Where, PIPE SIZE & PRESSURE DROP CALCULATIONS Sheet 7 OF 17 P Internal Design gage pressure (Kg/cm2) D Outside diameter of pipe as listed in tables of standards or specification or as measured (mm) S Allowable stress value (Kg/cm2) E quality factor. i) For a given velocity, the pressure drop varies inversely with the pipe size. MiA#x0!>.xSAeFH$)6pwOghE?dX! The allowance to be provided depends on the following factors: a) Size of pipe b) Quality of water c) Proportion of friction drop to total system resistance d) Location of pipe buried or above ground. Required Wall thickness, t = (8.98 + 1.5) / 0.875 = 11.97 mm. 45 degree elbows = 2 nos. Nominal Wall thickness, t = (7.20 + 1.5) / 0.875 = 9.94 mm. SELECTION OF A SUITABLE VELOCITY: The larger the velocity, the smaller is the pipe size and hence lower is the pipe cost. REV <> MJ{ /`@ gO%KF0 rQhHEEUm?3>la7LGA jl^5b>(4"Z0Z^))J%X[hq#Xe(sdYrVXMI"N6UP]\l-X3B.f q RECOMMENDED VELOCITY RANGE S.No FLUID 1 STEAM 1.1 SUPERHEATED STEAM 20 TO 75 m/s 1.2 SATURATED STEAM WET STEAM / EXHAUST STEAM 20 TO 40 m/s 1.3 20 TO 30 m/s PIPE SIZE & PRESSURE DROP CALCULATIONS Sheet 4 OF 17 2 WATER 2.1 PUMP SUCTION 0.5 TO 1.5 m/s 2.2 PUMP DELIVERY 1.0 TO 3.0 m/s 2.3 BOILER FEED DELIVERY 3.0 TO 6.0 m/s 2.4 CITY WATER 0.5 TO 1.5 m/s 3 OIL 3.1 HEAVY OIL (HEATED) 1 TO 2 m/s 3.2 LIGHT OIL 1 TO 2 m/s 4 GASES 4.1 COMPRESSED AIR 5 TO 15 m/s 4.2 NATURAL GAS 10 TO 30 m/s The above table indicates ranges of velocity, which in some cases are large. 0 BS 6700:2006 Design, installation, testing and maintenance of services supplying water for domestic use within buildings and their curtilages Specification NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW, NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Specification for, BSI Standards Publication Guide to the design, installation, testing and maintenance of services supplying water for domestic use within buildings and their curtilages -Complementary guidance to BS EN 806, Specification for installations inside buildings conveying water for human consumption Part 2: Design, Plumbing and drainage Part 1: Water services, Handbook on Plumbing Installation for Buildings, W Water Supplies Department Handbook on Plumbing Installation for Buildings, Plumbing Installation for Buildings Water Supplies, Eric Fleming-Construction Technology - An Illustrated Introduction [buildings, architecture-Wiley-Blackwell (2005), JKR Standard Specifications For Building Works 2005, STANDARD SPECIFICATIONS FOR CONSTRUCTION WORKS, The Potential of Rain Water Harvesting for Increasing Building and Urban Resilience: A Case Study of Coventry University and Coventry City Centre, Standard Specifications For Building Work, BS Gravity drainage systems inside buildings Sanitary pipework layout and calculation, BANGLADESH NATIONAL BUILDING CODE Volume 3 of 3 (Part 7 to Part 10, General Specification for Building ( 2007 Edition ) VOLUME 1 OF 2 We Build for Sustainability, Quality & Standards, TESTING AND COMMISSIONING PROCEDURE FOR PLUMBING AND DRAINAGE INSTALLATION IN GOVERNMENT BUILDINGS OF THE HONG KONG SPECIAL ADMINISTRATIVE REGION 2012 EDITION ARCHITECTURAL SERVICES DEPARTMENT THE GOVERNMENT OF THE HONG KONG SPECIAL ADMINISTRATIVE REGION, Third edition updated by Jonathan Hetreed, Code of practice for Building drainage (Formerly CP 301, Code of practice for Building drainage (Formerly CP 301, BS 8301, Domestic Product Guide Heating systems Industrial systems Refrigeration systems, The Water and Energy Implications of Bathing and Showering Behaviours and Technologies, Waterwise Report, Newnes Building Services Pocket Book This Page Intentionally Left Blank Newnes Building Services Pocket Book Second edition. Consider the system shown in Figure 10.2.6, and determine the pipe size required from the boiler to the unit heater branch line. l\T07ppNv[v3*~P8yO728ER-]|E%s . $O@bs"# 0000001775 00000 n All these variables are brought together in the DArcy-Weisbach equation (often referred to as the DArcy equation), and shown as Equation 10.2.1. NH,zha9MoF Vr&Gs aWY]u't;1 0b-ZO5GS_pN)N=Q4iYK%)FG1tt00p@ )HZZDR]`,260D$Ca" A Additional thickness, (mm) -To compensate for material removed in threading, grooving etc., required to make a mechanical joint. Pressure drop (as a general rule, the pressure drop should not normally exceed 0.1 bar/50 m. From factor 0.030, by following the row of figures to the right it will be seenthat: Since the application requires 270 kg/h, the 50 mm pipe would beselected. Pipe sizing is a crucial aspect of steam system design. Viewed in isolation, this velocity may seem low in comparison with maximum permitted velocities. From point C, draw a horizontal line across the pipe diameter scale (Point D). From the European Moody chart (Figure 10.2.4), Where: kS/D = 0.000 3 Re = 93 585: Friction factor (f) =0.005. %%EOF Refer attachment 3A for Viscosity of water and steam 3B for Viscosity of water and Liquid petroleum Products 3C for Viscosity of various Liquids 3D for Viscosity of gases and vapours Re = ((103 x 21.55 x 50 x 0.1985) / 2.936) = 72848.689 When the Reynolds number for a flow through a closed conduit is less than 2000, the flow is said to be LAMINAR. owhS8$] 6YF!P\8\WzC\@lrI3z. From point A, draw a horizontal line to the steam flowrate of 270 kg/h, and mark Point B. 793 0 obj <> endobj However, the selection of a suitable velocity is governed by the following system requirements. [emailprotected] STEP 4: CHECKING WHETHER THE PRESSURE DROP IS WITHIN THE ALLOWABLE LIMITS OR NOT. DATE It follows then, that if a reasonable velocity could be used for a particular fluid flowing through pipes, then velocity could be used as a practical sizing factor. The Procedure for line sizing is to first select a preliminary size based on assumed velocity and examine the suitability of the selected size from the point of view of the various system requirements discussed above. STEP 3: CALCULATION OF THE PRESSURE DROP FOR THE SELECTED PIPE SIZE FOR THE RECOMMENDED VELOCITY. ISSUED FOR CONSTRUCTION As the pipe size is not yet known in this example, an addition to the equivalent length can be used based onexperience. D>qmM}p1oIA T=,'D*|+EIie1w9SlK=0&vWv9uim8o(]Hva-#x/hhbp(mLp}d5 z}arKxBTjj/oV65v:L>xTvkF,dPP1N6aSlJ%RYh K(jb;=f The next lower factor is always selected; in this case, 0.030. For high temperature superheated steam mains, additional alloying elements, such as chromium and molybdenum, are included to improve tensile strength and creep resistance at hightemperatures. SIZING CALCULATION FOR UPS ii) When line pressures are low, select lower values of velocity to keep pressure drop low. All Rights Reserved. SS The running load should then be added on to the steam consumption to give the total steam load and the selected pipe checked to ensure it is still correctly sized. Academia.edu no longer supports Internet Explorer. endstream endobj 794 0 obj <>/Metadata 31 0 R/PageLayout/OneColumn/Pages 789 0 R/StructTreeRoot 35 0 R/Type/Catalog>> endobj 795 0 obj <>/Font<>>>/Rotate 0/StructParents 0/Type/Page>> endobj 796 0 obj <>stream v) In case of high temperature and high-pressure steam piping, pipe expansion will introduce problems of flexibility. - To provide for mechanical strength of pipe - To provide for corrosion and/or erosion - For cast iron pipe the following values of A shall apply: PIPE SIZE & PRESSURE DROP CALCULATIONS Sheet 9 OF 17 Centrifugally cast ------ 3.56mm Statically cast ------------ 4.57mm Y Refer attachment for coefficient values-taken from ANSI B31.1. Alternatively the pipe size can be calculated arithmetically. stream Typically, pipes are supplied in 6 metrelengths. (Refer attachment 5 taken from CRANE handbook) K1 = For 90 degree elbow = 30ft K2 = for 45 degree elbow = 16ft Z= (30 x 0.02 x 12) + (16 x 0.02 x 2) Z= 7.84 Therefore Pressure drop, P = (21.55 x 502 / 2 x 9.8) ((0.02 x 95)/0.1985) + 7.84) P = 47860.209 Kg/m2 P = 4.79 Kg/cm2 CASE-2 Selecting Higher Pipe Size: Let us calculate the pressure drop for a 10 (250NB) line. The friction factor can now be determined from the Moody chart and the friction head loss calculated from the relevant DArcy Equation.

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line sizing calculation pdf

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line sizing calculation pdf

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