smooth inside and out

Flowtite® FRP gets an A for its C.

As you know, one of the most important considerations when designing water distribution and transmission systems is head loss in pipes. The roughness coefficient, expressed as a C-value, is a major factor governing this hydraulic efficiency.

In basic terms, the higher the C-value, the lower the head loss and the better the flow of the water in the pipe. Because this is such a significant factor in determining the amount of energy required to deliver a given amount of water to a given destination — be that faucet, treatment plant or elsewhere — it directly impacts the size and number of pumps required. The C-value of a pipe directly affects the cost of building, operating and maintaining water systems.

Flowtite® FRP pipe has a Hazen-Williams flow coefficient (C-value) of 150. This compares extremely favorably with pipe materials such as ductile iron (140), concrete (100–140) or welded steel (100).

The diligent engineer will know that it’s advisable to calculate the energy consumption with a certain degree of accuracy and to account for head loss for any major project whether using the Hazen-Williams or the Darcy-Weisbach equations. FRP — and particularly FRP made using the Drostholm method (continuous-filament winding, chopped glass and silica) is the most commonly used FRP pipe globally for water and waste-water applications requiring design pressures up to 450 psi. This type of pipe presents consistently excellent C-values, and so serves to reduce potential head loss over time.

Aging, pitting and biofilms can be additional challenges, particularly in pipes that have been mortar-lined for corrosion protection. FRP has outstanding corrosion-resistance properties, making it relatively impervious to buildup. The buildup or encrustation in ferrous pipes, caused by tuberculation, rust and sedimentary deposits (e.g., magnesium and iron particulates), makes it necessary to conduct regular cleaning. Pumping efficiency is also reduced, which increases energy costs. So C-values are an important factor in the lifetime costs of a given pipe, affecting both operating and maintenance costs.

Of course, pipes have both an inside and an outside. The smooth inner surface of Flowtite® FRP is only part of the story. Corrosion-resistance also applies to the outside of the pipe. Attack on ferrous pipes by hot soil conditions or stray electrical currents from nearby pipelines can drastically shorten its lifespan. This simply doesn’t apply to Flowtite® FRP pipe.

So go with the flow!


P.S. Don’t just take my word for it. Check out this video to see it with your own eyes. We’ll discuss these and many more cost advantages at our next webinar.