TECHNICAL SUPPORT
Physical Dimensions & Weights       Flow Attributes       Flow Velocity       Flow Calculations       Abrasion Resistance      
UV Resistance       Temperature Expansion/Contraction Coefficients       Chemical Resistance      Engineering Properties

SmartDitch is manufactured by Penda Corporation, one of North America’s most advanced thermoformed plastics operations. Today, Penda is leveraging its global leadership in materials research, manufacturing and engineering to help you overcome your water conveyance challenges.

In this section of the site, you can find and download all the data and specs you need to integrate SmartDitch into your project.

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Physical Dimensions & Weights

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Flow Attributes
The Manning’s “n” coefficient of friction for the SmartDitch system is n=0.022.  This Manning’s coefficient can be used for all calculations required to determine maximum capacity and flow velocities for a lined ditch.

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Flow Velocity
The minimum flow velocity to maintain self-scouring is 2 ft/sec. Maximum velocities will vary dependent upon the slope of existing ditches. The minimum slope of 0.005 (½%) is recommended to maintain the self-cleansing velocity of the SmartDitch lining system.

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Flow Calculations
Flow rate calculations for the channel system are based on the standard hydraulic flow formula:

    Q = (1.49/n) A R ^2/3 S ^1/2

Where:
    Q = Total Flow
    N = Manning's Coefficient of Friction (0.022)
    A = area (sf)
    R = hydraulic radius (ft) [R = A / wetted perimeter]
    S = slope (%)

To calculate the hydraulic flow area & radius of each SmartDitch size, dimensions are provided below:

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UV Resistance
There is no evidence to suggest that ultraviolet degradation is a factor affecting the long-term service life of SmartDitch.  The outermost surface will be affected with discoloring. The resins used in SmartDitch have a high content of UV stabilizers that inhibit the physical and chemical process of UV-induced degradation. 

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Abrasion Resistance
SmartDitch has excellent abrasion resistance. Abrasion from stones or debris is one of the most common durability concerns for SmartDitch especially when the effluent flows at high velocities.  While there are no widely standardized testing procedures; various types of test results have shown that it takes longer to abrade through HDPE than concrete or metallic surfaces.

The extent of abrasion in the invert of the SmartDitch channel sections will depend upon the type of abrasive, frequency that the material is in the channel and velocity of flow.

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Temperature Expansion/Contraction Coefficients
The thermal coefficient of axial expansion and contraction for SmartDitch is 7 x 10 ^-5 inch/inch/degree F.

SmartDitch’s plastic corrugated design allows it to easily withstand freeze-thaw cycles.  The effect of low temperatures on polyethylene materials is unique, the modulus of elasticity increases as temperatures are lowered. In effect, the material becomes stiffer but retains its ductile qualities. The actual low temperature embrittlement for the HDPE resin used in manufacturing SmartDitch is -131°F. 

The coefficient of linear expansion for unrestrained HDPE is approximately ten times that of metal or concrete. While the potential for expansion (or contraction) is large when compared with that of metal or concrete, note that the modulus of elasticity for polyethylene is substantially lower than that of alternative materials (less rigid).

This implies that the degree of movement associated with a specific temperature change may be higher for the polyethylene, but the stress associated with restraint of this movement is significantly less. This means that SmartDitch will therefore move with the freeze/thaw movements associated with the ground heaves without damage.

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Chemical Resistance
SmartDitch is manufactured from HDPE – one of the most chemically inert materials available.  Normal ground water, storm water, salt water, or agricultural runoff typically has no effect on SmartDitch channels.

Some regions of the country have naturally occurring conditions which cause unusually low (acidic) or high (alkaline) pH in the soil and ground water.  SmartDitch is ideal for both acid and alkali environments. 

The heavy use fertilizers on golf courses and in agriculture can detrimentally affect the pH and chemical composition of runoff water. High concentrations of phosphates and nitrates can be common is these situations. SmartDitch is not affected by these conditions.

In a salt water environment, galvanic/electro-chemical attack can occur to more traditional materials such as metal or steel reinforced concrete.  As HDPE is an insulator, SmartDitch is not affected by galvanic attack.

For a review of chemical resistance of polyethylene material to common selected substances*, see the chart below.

R   =   Material is generally resistant (Specimen swells <3% or has weight loss of <0.5% and elongation at break is not significantly changed).

C   =  Material has limited resistant only and may be suitable for some conditions (Specimen swells 3% - 8% at weight and loss of 0.5% - 5% and/or elongation at break decreased by <50%).

*      Information gathered from Chemical & Abrasion Resistance of Corrugated Polyethylene Pipe, Corrugated Polyethylene Pipe Association. Though different in physical design, SmartDitch maintains the same resin cell classification as the samples in this report.  A more complete listing of polyethylene’s chemical resistance can be obtained by contacting the Corrugated Polyethylene Pipe Association

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Engineering Properties
SmartDitch is manufactured with a HDPE resin that provides excellent mechanical properties. These properties are instrumental in providing a premier, flexible, thermoformed plastic ditch-lining system. The following table highlights some of the more important design properties of SmartDitch. Please contact your SmartDitch sales representative if additional design data is required.

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