How to Reduce Frictional Loss in Pipes

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Frictional loss in pipes affects water flow and pressure, and affects the performance of fixtures and appliances.

Here, we’ve shared some of the ways to prevent frictional loss in your home’s pipes and plumbing.

๐Ÿ“Œ Key Takeaways:

  • Frictional loss, or friction loss, is a measure of the energy loss that occurs in a piping system due to resistance.
  • There are several methods of calculating friction loss, and the Darcy Weisbach formula is most commonly used in engineering applications.
  • You can reduce friction loss in pipes by removing contaminants causing pipe friction with a water treatment system, increasing the diameter of the pipe, and straightening out pipe runs.

๐Ÿ“‰ What Is Friction Loss?

Friciton loss is used to measure how much energy is lost in a plumbing or piping system due to resistance.

Water flowing through your pipes carries energy, but when the water meets resistance, it loses some of this energy, resulting in friction loss.

So, the greater the friction loss, the more energy that the water loses, and the lower the pressure/the slower the flow.

Low water flow due to friction loss in pipes

๐Ÿ”ข How to Calculate Friction Loss

The loss due to friction in pipes is calculated with the Darcy Weisbach formula:

โ„Ž๐ฟ=๐‘“ ร— ๐ฟ/๐ท ร— ๐‘ฃ^2/2๐‘”

Here’ what the expressions in the formula mean:

  • HL is energy loss
  • L is the pipe length
  • D is the pipe diameter
  • V is the average flow velocity of the liquid
  • F is the friction factor (whether you’re dealing with laminar flow or turbulent pipe flow determined your method of obtaining F. Laminar flow is a steady, smooth flow, while turbulent flow is an irregular, chaotic flow)
  • G is acceleration due to gravity

๐Ÿ” What Causes Friction Loss In Pipes?

Here’s an overview of some of the most common causes of friction loss in piping systems:

  • Pipe roughness: Water flows faster through a smooth pipe compared to a pipe with a rough internal surface. If you have rough internal pipe surfaces, fluids need to work harder to travel through the pipes.
  • Water quality & parameters: The quality of the water flowing through your piping system affects the likelihood of, and the severity of, pipe friction loss. Certain contaminants, like sediment and hardness minerals, contribute to roughness on the pipe surfaces. Acidic water will also corrode certain pipe materials, increasing surface roughness and reducing fluid flow.
  • Internal pipe diameter: Pipes with a smaller diameter are more likely to cause friction loss than wider pipes because the ratio of pipe surface to water volume is higher.
  • Pipe inclines and slopes: If you have a pipe that’s on an incline, it’ll have a higher pipe friction and a reduced flow rate than a straight pipe. The reason for this is that water has to work against gravity it it’s traveling up an incline, which will increase resistance and result in a pressure drop.
  • Pipe length: Water traveling through longer pipes will experience more friction loss overall compared to water traveling through shorter pipes. The longer the pipe and the further the water has to travel, the longer the water will meet resistance, and the slower the end flow rate.
  • The presence of fittings and valves: Aside from the pipes themselves, the fittings and valves within your plumbing system may also have an impact on water flow, increasing friction and reducing pressure.
limescale in pipe
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โš ๏ธ Effects Of Friction Loss

Some of the effects of friction loss in pipes are as follows:

Reduced Water Flow From Fixtures

Found yourself waiting longer than usual to fill a glass of water? Are your showers less powerful than they used to be? You might be noticing the effects of reduced water flow as a result of friction loss in your pipes.

The greater the frictional loss, the slower the water flow at the fixture. So, if your water flow is very slow and there aren’t any external factors to blame, an issue with your pipes may have caused too much friction loss.

Worn Pipes And Fittings

Frictional loss caused by increasing surface roughness can also result in worn pipes and fittings.

As your pipes become more and more closed off, the pressure in the pipes will increase, putting extra stress on the system and potentially damaging the fittings.

This is especially likely if you have an unsteady flow of water that has to weave around residue and barriers, rebounding off the sides of your pipes as it does so.

Worn pipes and fittings

Reduced Appliance Efficiency

Friction loss – and therefore energy loss – also affects the performance of water-using appliances.

If pipe flow is reduced, the volume of fluid flowing into appliances will also be reduced. This pressure difference could reduce the efficiency of your appliances and result in excess energy or water use to achieve the same end result.

Damaged Pumps

If you’re on a private well system, frictional loss and reduced pipe flow will wear out and damage your well pump.

A well pump will need to deliver more power to maintain the flow of water through a pipe with a high friction factor in order to prevent pressure loss within the plumbing system.

A pump that’s working overtime will become worn at a faster rate, and may even burn out.

๐Ÿ”ง 4 Methods To Prevent Frictional Loss In Pipes

Here are our 4 recommended methods to prevent frictional loss in pipes.

Install A Water Filter or Water Softener

Sediment and limescale are two of the most common causes of internal pipe roughness. These contaminants can leave deposits inside your pipes, causing surface roughness that reduces water flow.

The best way to reduce friction loss in pipes, therefore, is to install a water treatment system that removes these contaminants before water enters your plumbing system.

If you’re on a private well and you have sediment-rich water, install a whole-home sediment filter at the main water pipe’s point of entry into your home.

If you have hard or very hard water (whether you use a municipal supply or a private well), consider installing a point-of-entry water softener to remove hardness minerals upstream of your hot water heater. This should protect your hot and cold piping system from rough scale.

Not sure whether or not your water quality is to blame for reduced water pressure or flow in your plumbing? Conduct a water test to determine exactly what your water contains, and whether any of these contaminants may be responsible for causing friction loss in your pipes.

Springwell iron filter and water softener

Prevent Corrosion

Corrosion is another cause of rough internal pipe walls. So, it makes sense that reducing or preventing corrosion will prevent friction loss in your pipes.

There are a few different methods of preventing corrosion, depending on the cause.

If contaminants in your water are corroding your pipe material, install a whole-home water treatment system that will address these contaminants. You can also use an internal coating solution to prevent damage to the pipe surfaces from the corrosive elements in your water supply.

If your pipes are badly corroded, consider replacing them with pipes that are resistant to corrosion, like PEX piping.

Increase Pipe Diameter

If you have narrow pipes in your plumbing system, water will need to work harder to reach its destination.

So, increasing your pipe diameter even by a few inches can help you to avoid friction loss and flow resistance in your pipe system.

Just make sure that the pipes are still suitably sized for their purpose. Your local plumbing professional should be able to offer guidance and advice if you need it.

Worker measuring pipe diameter with a caliper

Straighten Out Pipe Runs

Pipes with a lot of twists and turns are likely to have issues with reduced flow rate and friction loss.

If possible, limit bends in your home’s piping system, so the water can take a straighter path to reach its destination.

This is something you’ll need to discuss with your plumber, since your existing plumbing and pipes probably follow a route through your home that makes the most sense, regardless of how many bends are in their path.

๐Ÿ”š Final Word

Friction loss in pipe systems is something that’s mainly a concern in engineering applications.

However, if you are worried about the effects of friction loss in your own plumbing system, this guide should have helped you to determine the cause of the issue and the best methods of resolution.

Our advice is to speak to a plumber if you have issues with water pressure and flow in your home. They’ll help you to consider all the possible causes of the problem and resolve it with the right course of action.

  • Brian Campbell
    President & CEO, CWS, CWR

    Brian Campbell, a WQA Certified Water Specialist (CWS) and Certified Water Treatment Representative (CWR) with 5+ years of experience, helps homeowners navigate the world of water treatment. After honing his skills at Hach Company, he founded his business to empower homeowners with the knowledge and tools to achieve safe, healthy water. Brian's tested countless devices, from simple pitchers to complex systems, helping his readers find the perfect fit for their unique needs.

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