Stick This in Your Pipe

Information Found at the Following Website

• http://microhydropower.net/index.php

Pipe can be a Considerable Costup to 40%

Factors to Consider

• surface roughness, • design pressure, • method of jointing, • weight and ease of installation, • accessibility of the site, • terrain, • soil type, • design life and maintenance, • weather conditions, • availability, • relative cost, • likelihood of structural damage.

Considerations

• Pipes are generally supplied in standard lengths and have to be joined together on site.

• Penstock pipelines can either be surface mounted or buried underground. The decision will depend on the pipe material, the nature of the terrain and environmental considerations.

Burying Pipe

• Burying a pipe line removes the biggest eyesore of a hydro scheme and greatly reduces its visual impact. However, it is vital to ensure a buried penstock is properly and meticulously installed because any subsequent problems such as leaks are much harder to detect and rectify.

Types of Pipes

• The following materials can be considered for use as penstock pipes in micro hydro schemes: – mild steel, – unplastified polyvinyl chloride (uPVC), – high density polyethylene (HDPE), – spun ductile iron, – asbestos cement, – prestressed concrete, – wood stave, – glass reinforced plastic (GRP).

• PVC and HDPE are the most common used materials.

Pipe loss charts modified from Scott Suddreth’s Hydro Matrix

Excel sheet

PIPE FRICTION LOSS 

Polyethylene SDR - Pressure Rated Pipe

Pressure Loss from Friction in Feet of Head per 100 Feet of Pipe

Flow US

GPMPipe Diameter, Inches

   

  0.5 0.75 1 1.25 1.5 2 2.5 3  

40   21.5 10.2 3.02 1.27 0.44  

45   26.8 12.7 3.75 1.59 0.55  

50   32.5 15.4 4.55 1.91 0.67  

55   18.3 5.43 1.96 0.81  

60   21.5 6.4 2.7 0.94  

65   23.8 7.41 3.13 1.08  

70   28.7 8.49 3.59 1.24  

75   32.6 9.67 4.07 1.4  

80   10.9 4.58 1.59  

85   12.2 5.13 1.77  

90   13.5 5.71 1.98  

95   15 6.31 2.19  

100   16.5 6.92 2.42  

150   34.5 14.7 5.11  

200   25 8.7  

300   18.4  

PIPE FRICTION LOSS - PVC Class 160 PSI Plastic Pipe 

Pressure Loss from Friction in Feet of Head per 100 Feet of Pipe

 

Flow US GPM Pipe Diameter, Inches

  1 1.25 1.5 2 2.5 3 4 5 6 8 10

40   11.4 5.89 1.98 0.78 0.3 0.09 0.02  

45   14.2 7.34 2.48 0.97 0.37 0.12 0.04  

50   17.2 8.92 3.01 1.2 0.46 0.14 0.04  

55   20.5 10.6 3.59 1.43 0.55 0.16 0.05  

60   24.1 12.5 4.21 1.66 0.64 0.18 0.07 0.02  

70   16.6 5.61 2.21 0.85 0.25 0.09 0.03  

80   21.3 7.18 2.83 1.08 0.32 0.12 0.04  

90   8.92 3.52 1.36 0.39 0.14 0.07  

100   10.9 4.28 1.66 0.48 0.18 0.07 0.02  

150   23.2 9.06 3.5 1.04 0.37 0.16 0.05  

200   15.5 5.96 1.75 0.62 0.28 0.07 0.02

250   23.4 9.05 2.65 0.94 0.42 0.12 0.05

300   12.6 3.73 1.34 0.58 0.16 0.05

Lets do some examples:

• Turtle Island• 140 ft head • 4” HDPE (High Density Poly Ethylene)• Ok lets do 3” since it is on the chart.

• What is the best size of PVC pipe to use for 100 gpm with 100’ head? Keep loss below 5%.

• How about 30 ft head?