Engineering & Design Data Engineering & Design Data - PVC Pipe Supplies

PVC & CPVC Corrosion Resistant Industrial Pressure Pipe Engineering & Design Data

Engineering & Design Data

Hydraulic Shock

Hydraulic shock is the term used to describe the momentary pressure rise in a piping system which results when the liquid is started or stopped quickly. This pressure rise is caused by the momentum of the fluid; therefore, the pressure rise increases with the velocity of the liquid, the length of the system from the fluid source, or with an increase in the speed with which it is started or stopped. Examples of situations where hydraulic shock can occur are valves, which are opened or closed quickly, or pumps, which start with an empty discharge line. Hydraulic shock can even occur if a high speed wall of liquid (as from a starting pump) hits a sudden change of direction in the piping, such as an elbow. The pressure rise created by the hydraulic shock effect is added to whatever fluid pressure exists in the piping system and, although only momentary, this shock load can be enough to burst pipe and break fittings or valves.

A formula, which closely predicts hydraulic shock effects is:

Where: p = maximum surge pressure, psi HS Example v = fluid velocity in feet per second

C = surge wave constant for water at 73?F

23.9 + 23.9

*SG = specific gravity of liquid ( If SG is 1, then p = VC )

Example: A 2" PVC schedule 80 pipe carries a fluid with a specific gravity of 1.2 at a rate of 30 gpm and at a line pressure of 160 psi. What would the surge pressure be if a valve were suddenly closed?

HFrSomExtaabmlep1l:eC = 23.9

p = (3.35) (26.3) = 88 psi

23.9 + 23.9

Total line pressure = 88 + 160 = 248 psi

Schedule 80 2" PVC has a pressure rating of 400 psi at room temperature.

Therefore, 2" schedule 80 PVC pipe is acceptable for this application.

The total pressure at any time in a pressure-type system (operating plus surge or water hammer) should not exceed 150 percent of the pressure rating of the system.

Compensating for Expand & Contract

Table I - C-Surge Wave Constant

Pipe Size (in.)

PVC

Sch. 40

Sch. 80

1/8

34.7

41.3

1/4

33.6

39.3

3/8

30.2

35.6

1/2

29.3

34.2

3/4

26.4

30.9

1

25.4

29.6

1-1/4

23.0

27.0

1-1/2

21.8

25.7

2

20.0

23.9

2-1/2

20.8

24.5

3

19.4

23.1

3-1/2

18.6

22.2

4

17.9

21.5

5

16.8

20.3

6

16.0

20.0

8

15.0

18.8

10

14.3

18.3

12

13.8

18.1

14

13.7

18.1

16

13.7

17.9

18

13.7

17.8

20

13.3

17.7

24

13.1

17.6

CPVC

Sch. 40

Sch. 80

32.9

39.4

31.8

37.5

28.4

33.8

27.6

32.3

24.8

29.1

23.8

27.8

21.5

25.3

20.4

24.1

18.6

22.4

19.4

22.9

18.1

21.6

17.3

20.7

16.7

20.1

15.6

19.0

14.9

18.6

13.9

17.5

13.3

17.1

12.8

16.9

12.7

16.8

12.7

16.7

12.7

16.6

12.4

16.5

12.2

16.3

Proper design when laying out a piping system will eliminate the possibility of hydraulic shock damage.

The following suggestions will help in avoiding problems:

1. In a plastic piping system, a fluid velocity not exceeding 5 ft./sec. will minimize hydraulic shock effects, even with quickly closing valves, such as solenoid valves.

2. Using actuated valves which have a specific closing time will eliminate the possibility of someone inadvertently slamming a valve open or closed too quickly. With pneumatic and airspring actuators, it may be necessary to place a valve in the air line to slow down the valve operation cycle.

3. If possible, when starting a pump, partially close the valve in the discharge line to minimize the volume of liquid, which is rapidly accelerating through the system. Once the pump is up to speed and the line completely full, the valve may be opened.

4. A check valve installed near a pump in the discharge line will keep the line full and help prevent excessive hydraulic shock during pump start-up.

8

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CTS plumbing

PVC & CPVC Corrosion Resistant Industrial Pressure Pipe Engineering & Design Data

Head Loss Characteristics

0.9

1.0

Head Loss Characteristics of Water

.1 .01

.2

Flow Through Rigid Plastic Pipe--

3000 30

.3

Nomograph

.02

.4

24

.01

1.5

2000

.03

.6

The nomograph on the following page provides approximate values for a wide range of plastic pipe sizes. More

20

.04

.02 18

.8

.06

16

.03

.08

2.0

precise values should be calculated from the Williams &

1000

14

.04

.1

.2

Hazen formula. Experimental test value of C (a constant for

900

800

12

.4

inside pipe roughness) ranges from 155 to 165 for various types of plastic pipe. Use of a value of 150 will ensure con-

700 10

600

9

.1

.2

.6 .8

servative friction loss values. Since directional changes and restrictions contribute the most head loss, use of head loss

500

8

400

7

.3

.4 .2

3.0

.2 .4

HdaStaEfoxracmompplaerable metal valves and fittings will provide

conservative values when actual values for PVC and CPVC

300

fittings and valves are not available.

23.9 + 23.9

.6

6 5

.3

(1)

.8

.4

1.0

.6 .8 4.0

.6

4.5

Williams & Hazen formula.

200

4

150

.8

2.0

5.0

1.0

3.0 (2)

3

4.0

6.0

100

2.5

90

2

6.0

(3)

3

7.0

8.0

Where: f = Friction head in feet of water per 100 feet

80 70

2

4

10

(3)

8.0

60

6

9.0

50

8

20

10

10

d =Inside diameter of pipe in inches

40

30 11

g = Flowing gallons per minute C = Constant for inside roughness of the pipe

(C = 150 for thermoplastic pipe)

40

30

1.0

20

12

.9

60 30

13

.8 20

80

40

100

14 15

The nomograph is used by lining up values on the scales

.7 60

16

by means of a ruler or straight edge. Two independent

10

.6

80

200

17 18

variables must be set to obtain the other values. For example line (1) indicates that 500 gallons per minute

.5 10

100 300 400

19 20

may be obtained with a 6-inch inside diameter pipe at a

9

.4

200

22

head loss of about 0.65 pounds per square inch at a velocity

8

600

24

7

300

of 6.0 feet per second. Line (2) indicates that a pipe with a 2.1 inch inside diameter will give a flow of about 60 gallons per minute at a loss in head of 2 pounds per square inch

6

.3

5

800

400

1000

600

26 28 30

piCneorgmo1i0n0pgfeefrneotsmoaftapipnipigpee. fL2oi.nr1e-iEn(3cxh)paiannnsdidddeo&tdteiadCmloiennteetr(r3tao)csothnoewofth2at

4 .2

3

800 1000

2000

inches inside diameter the head loss goes from 3 to 4

40

pounds per square inch in obtaining a flow of 70 gallons

per minute. Flow velocities in excess of 5.0 feet per second

2

50

are not recommended.

1.5

NCoTmSogpralpuh mcoubritnesgy of Plastics Pipe Institute, a division of

The Society of The Plastics Industry.

1.0

.9

.8

.7

.6

.5

Water flow in gallons per minute Inside diameter of pipe in inches Head loss in PSI per 100 ft. of pipe Head loss in feet per 100 ft. of pipe Water velocity in feet per second

?2012 Georg Fischer Harvel LLC ? 300 Kuebler Road, Easton, PA 18040 ? 610-252-7355 ? Fax: 610-253-4436 ?

9

3ED(L)

PVC & CPVC Corrosion Resistant Industrial Pressure Pipe Engineering & Design Data

Flow Velocity & Friction Loss

HS Example

Friction Loss

23.9 + 23.9

Friction loss through PVC and CPVC pipe is most commonly obtained by the use of the Hazen-Williams equations as expressed below for water:

Where: f = friction head of feet of water per 100' for the specific pipe size and I.D.

C = a constant for internal pipe roughness. 150 is the commonly

HS Eaxcacmeppteldevalue for PVC and CPVC pipe. G = flow rate of gallons per minute (U.S. gallons).

di = inside diameter of pipe in inches.

23.9 + 23.9

Compared to other materials on construction for pipe, thermoplastic pipe smoothness remains relatively constant throughout its service life.

Water Velocities

Velocities for water in feet per second at different GPM's and pipe inside diameters can be calculated as follows: Compensating for Expand & Contract

Where: V = velocity in feet per second G = gallons per minute A = inside cross sectional area in square inches CTS plumbinGgF Harvel does not recommend flow velocities in excess of five feet per second for closed-end systems, particularly in pipe sizes 6" and larger. Contact GF Harvel tech services for additional information.

Thrust Blocking

In addition to limiting velocities to 5'/sec., especially with larger diameters (6" and above), consideration should be given to stresses induced with intermittent pump operation, quick opening valves and back flow in elevated discharge lines. Use of bypass piping with electrically actuated time cycle valves or variable speed pumps and check valves on the discharge side are suggested with the higher GPM rates. Thrust blocking should be considered for directional changes and pump operations in buried lines 10" and above, particularly where fabricated fittings are utilized. Above grade installations 10" and above should have equivalent bracing to simulate thrust blocking at directional changes and for intermittent pump operations. Thrust blocking of directional changes and time cycle valves are also recommended for large diameter drain lines in installations such as large swimming pools and tanks. Use of appropriate pump vibration dampers are also recommended.

THRUST IN POUNDS FROM STATIC INTERNAL PRESSURE

Pipe Socket For Plug, For For Size Depth 60? Ell, 22.5? 45?

(in.) (in.H) S ECxaapmTepele Ell Ell

For Joint 90? Ell 90? Resist. Safety Ell To Thrust Factor

6

6

7,170 2,800 5,480 10,140 37,464 3.7

8

6 11,240 4,380 8,590 15,890 48,774 23.93.+1 23.9

10 8 16,280 6,350 12,440 23,020 81,054 3.5

12 8 23,040 8,990 17,600 32,580 102,141 3.1

14 9 26,610 10,380 20,330 37,630 115,752 3.1

16 10 34,910 13,620 26,670 49,360 150,798 3.1

18 12 44,290 17,270 33,840 62,630 203,577 3.3

20 12 43,410 16,540 32,400 59,970 226,194 3.8

24 14 61,040 23,810 46,640 86,310 316,500 3.7

Compensating for Expand & Contract

3ED(L) 2S

CTS p3lxum360b,i0n00g x 2.375 x 4.08

2 x 500

Socket depths are from ASTM D 2672 for belled-end PVC pipe. Working pressures utilized for the tabulation above are for Schedule 80 2"- 18" sizes and SDR 160 psi for 20" and 24" sizes.

The calculation for thrusts due to static internal pressure is:

Thrust =

x = 1.0 for tees, 60? ells, plugs and caps, .390 for 22-1/2? bends, .764 for 45? ells, 1.414 for 90? ells

Joint Resistance to Thrust= (O.D.) ( ) (socket depth) (300 psi) 300 psi = Minimum cement shear strength with good field cementing technique.

Compensating for Expand & Contract

3ED(L)

2S

CTS plumbing

3 x 360,000 x 2.375 x 4.08

2 x 500

10

?2012 Georg Fischer Harvel LLC ? 300 Kuebler Road, Easton, PA 18040 ? 610-252-7355 ? Fax: 610-253-4436 ?

PVC & CPVC Corrosion Resistant Industrial Pressure Pipe

Engineering & Design Data

HS Example

23.9 + 23.9

Friction Loss Through Fittings

Friction loss through fittings is expressed in equivalent feet of the same pipe size and schedule for the system flow rate. Schedule 40 head loss per 100' values are usually used for other wall thicknesses and standard iron pipe size O.D.s.

Average Friction Loss for PVC and CPVC Fittings in Equivalent Feet of Straight Run Pipe

Size (in.)

Item

1/2 3/4 1 1-1/4 1-1/2 2 2-1/2 3 4 6 8 10 12 14 16 18 20 24

Tee Run Tee Branch 90? Ell 45? Ell

1.0 1.4 1.7 2.3 3.8 4.9 6.0 7.3 1.5 2.0 2.5 3.8 0.8 1.1 1.4 1.8

2.7 4.0 4.9 6.1 7.9 12.3 14.0 17.5 20.0 25.0 27.0 32.0 35.0 42.0 8.4 12.0 14.7 16.4 22.0 32.7 49.0 57.0 67.0 78.0 88.0 107.0 118.0 137.0 4.0 5.7 6.9 7.9 11.4 16.7 21.0 26.0 32.0 37.0 43.0 53.0 58.0 67.0 2.1 2.6 3.1 4.0 5.1 8.0 10.6 13.5 15.5 18.0 20.0 23.0 25.0 30.0

Values 10" - 24": Approximate values from Nomograph.

Pressure Drop in Valves and Strainers

Pressure drop calculations can be made for valves and strainers for different fluids, flow rates, and sizes using the CV values and the following equation:

CWohmerpe:ePns=atPinregssfuorre

EdrxoppainndP&SI;Cfeoent torfawctater

=

PSI .4332

G = Gallons per minute CV = Gallons per minute per 1 PSI pressure drop

CV Factors GPM

Item

True Union Ball Valve Single Entry Ball Valve QIC Ball Valve True Check Ball Valve Y-Check Valve 3-Way Flanged Ball Valve Needle Valve Full Open Angle Valve Y-Strainer (clean screen) Simplex Basket Strainer (clean screen) Duplex Basket Strainer (clean screen)

1/4 3/8 1/2

1.0

8.0 8.0

1.0

8.0 8.0

-

- 8.0

1.0

3.0 4.6

-

- 5.0

-

- 5.0

5.0

7.5 8.0

1.0

- 5.0

-

- 3.8

-

- 6.0

-

- 5.0

CTS plumbing

Size (in.)

3/4

1

1-1/4 1-1/2

2

15.0 29.0 75.0 90.0 140.0

16.0 29.0 75.0 90.0 140.0

15.0 29.0 75.0 90.0 140.0

10.0 28.0 45.0 55.0

90.0

6.0 12.5 40.0 40.0

65.0

10.0 -

163.0E- D(L)

-

45.0 -

55.0 -

10.0

16.0 2S -

45.0

70.0

6.6

8.4 20.0 25.0

35.0

9.5

29.30x 360,000-x 2.37540x.04.08 55.0

6.0

7.0

2 x- 500 28.0

35.0

2-1/2

330.0 330.0

225.0 130.0

60.0 -

3

480.0 480.0

324.0 160.0 200.0

60.0 125.0 80.0

4

600.0 600.0

345.0 250.0 350.0

95.0 155.0 100.0

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11

Flow Velocity & Friction Loss ? Schedule 40

12

Schedule 40

Friction Friction

Friction Friction

Friction Friction

Flow Flow Loss Loss Flow Loss Loss Flow Loss Loss

Rate Velocity (Ft.Water (psi/ Velocity (Ft.Water (psi/ Velocity (Ft.Water (psi/

(GPM) (ft/sec.) 100ft.) 100ft.) (ft/sec.) 100ft.) 100ft.) (ft/sec.) 100ft.) 100ft.)

?2012 Georg Fischer Harvel LLC ? 300 Kuebler Road, Easton, PA 18040 ? 610-252-7355 ? Fax: 610-253-4436 ?

1/8"

1/4"

3/8"

0.25 1.64 6.54 2.83 0.86 1.36 0.59 0.46 0.29 0.12

0.50 3.27 23.60 10.23 1.72 4.90 2.12 0.91 1.04 0.45

0.75 4.91 50.00 21.68 2.59 10.38 4.50 1.37 2.20 0.96

1 6.55 85.18 36.93 3.45 17.68 7.66 1.82 3.75 1.63

2 13.09 307.52 133.31 6.90 63.82 27.67 3.65 13.55 5.88

5

17.25 348.29 150.98 9.11 73.96 32.06

7

12.76 137.93 59.79

10

Friction Friction

Friction Friction

Friction Friction

Friction Friction

Friction Friction

Flow

Flow Loss Loss Flow Loss Loss Flow Loss Loss Flow Loss Loss Flow Loss Loss Flow

Rate

Velocity (Ft.Water (psi/ Velocity (Ft.Water (psi/ Velocity (Ft.Water (psi/ Velocity (Ft.Water (psi/ Velocity (Ft.Water (psi/ Rate

(GPM)

(ft/sec.) 100ft.) 100ft.) (ft/sec.) 100ft.) 100ft.) (ft/sec.) 100ft.) 100ft.) (ft/sec.) 100ft.) 100ft.) (ft/sec.) 100ft.) 100ft.) (GPM)

1/2"

3/4"

1"

1-1/4"

1-1/2"

2"

2-1/2"

3"

1 1.13 1.16 0.50 0.63 0.28 0.12 0.39 0.09 0.04 0.22 0.02 0.01 0.16 0.01 0.00 0.10 0.00 0.00 0.07 0.00 0.00 0.04 0.00 0.00 1

2 2.25 4.19 1.82 1.26 1.03 0.44 0.77 0.31 0.13 0.44 0.08 0.03 0.32 0.04 0.02 0.19 0.01 0.00 0.14 0.00 0.00 0.09 0.00 0.00 2

5 5.63 22.88 9.92 3.16 5.60 2.43 1.93 1.69 0.73 1.10 0.43 0.19 0.81 0.20 0.09 0.49 0.06 0.03 0.34 0.02 0.01 0.22 0.01 0.00 5

7 7.88 42.66 18.49 4.42 10.44 4.53 2.70 3.14 1.36 1.55 0.81 0.35 1.13 0.38 0.16 0.68 0.11 0.05 0.48 0.05 0.02 0.31 0.02 0.01 7

10 11.26 82.59 35.80 6.31 20.21 8.76 3.86 6.08 2.64 2.21 1.57 0.68 1.62 0.73 0.32 0.97 0.21 0.09 0.68 0.09 0.04 0.44 0.03 0.01 10

15

4"

9.47 42.82 18.56 5.78 12.89 5.59 3.31 3.32 1.44 2.42 1.55 0.67 1.46 0.45 0.20 1.02 0.19 0.08 0.66 0.07 0.03 15

20 0.51 0.03 0.01 12.63 72.95 31.63 7.71 21.96 9.52 4.42 5.65 2.45 3.23 2.64 1.15 1.95 0.77 0.34 1.37 0.33 0.14 0.88 0.11 0.05 20

25 0.64 0.05 0.02

5"

9.64 33.20 14.39 5.52 8.55 3.71 4.04 4.00 1.73 2.44 1.17 0.51 1.71 0.49 0.21 1.10 0.17 0.07 25

30 0.77 0.06 0.03 0.49 0.02 0.01 11.57 46.54 20.17 6.62 11.98 5.19 4.85 5.60 2.43 2.92 1.64 0.71 2.05 0.69 0.30 1.32 0.24 0.10 30

35 0.89 0.08 0.04 0.57 0.03 0.01

7.73 15.94 6.91 5.65 7.45 3.23 3.41 2.18 0.94 2.39 0.92 0.40 1.54 0.32 0.14 35

40 1.02 0.11 0.05 0.65 0.04 0.02

8.83 20.41 8.85 6.46 9.54 4.14 3.90 2.79 1.21 2.73 1.18 0.51 1.76 0.41 0.18 40

45 1.15 0.13 0.06 0.73 0.04 0.02

6"

9.94 25.39 11.00 7.27 11.87 5.15 4.39 3.47 1.51 3.07 1.46 0.63 1.99 0.51 0.22 45

50 1.28 0.16 0.07 0.81 0.05 0.02 0.56 0.02 0.01 11.04 30.86 13.38 8.08 14.43 6.25 4.87 4.22 1.83 3.41 1.78 0.77 2.21 0.61 0.27 50

60 1.53 0.23 0.10 0.97 0.08 0.03 0.67 0.03 0.01

9.69 20.22 8.77 5.85 5.92 2.56 4.10 2.49 1.08 2.65 0.86 0.37 60

70 1.79 0.30 0.13 1.14 0.10 0.04 0.79 0.04 0.02

6.82 7.87 3.41 4.78 3.32 1.44 3.09 1.15 0.50 70

75 1.92 0.34 0.15 1.22 0.11 0.05 0.84 0.05 0.02

7.31 8.94 3.88 5.12 3.77 1.63 3.31 1.30 0.56 75

80 2.04 0.39 0.17 1.30 0.13 0.06 0.90 0.05 0.02

7.80 10.08 4.37 5.46 4.25 1.84 3.53 1.47 0.64 80

GF Harvel recommends that Flow Velocities be maintained at or below 5 feet per second in large diameter piping systems ( i.e. 6" diameter and larger) to minimize the potential for hydraulic shock. Refer to GF Harvel engineering section entitled "Hydraulic Shock" for additional information. Friction loss data based on utilizing mean wall dimensions to determine average ID; actual ID may vary. Georg Fischer Harvel LLC 2012 All Rights Reserved

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