Hazen-Williams is simpler to use than D’Arcy-Weisbach where The Hazen- Williams equation has narrow applicable ranges for Reynolds numbers and pipe. same as the H-W nomograph in the CERM. to solve several problems (example Friction head loss (ft H2O per ft pipe) in water pipes can be estimated with the empirical Hazen-Williams equation.

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By using this site, you agree to the Terms of Use and Privacy Policy. Why is it that when I try to solve problems using nomographs, the answers are typically errored signifigantly. Thanks for the help.

Major loss h f is the energy or head loss expressed in length units – think of it as energy per unit weight of fluid due to friction between the moving fluid and the pipe wall. I looked at problem 3. Typical C factors used in design, which take into account some increase in roughness as pipe ages are as follows: A result of adjusting the exponents is that the value of C appears more like a constant over a wide range of the other parameters.

For other liquids or gases, the Darcy-Weisbach method should be used. When used to calculate the head loss with the International System of Unitsthe equation becomes: It is used in the design of water pipe systems [1] such as fire sprinkler systems[2] water supply networksand irrigation systems.


The Hazen-Williams method is valid for water flowing at ordinary temperatures of 40 to 75 o F 4 to 25 o C through pressurized pipes. Use feet and seconds units Use meters and seconds units Pipe Length, L ft: Use feet and seconds units Use meters and seconds units. Archived from the original on Sign up for a new account in our community.

Use dmy dates from September Hazen-Williams is simpler than Darcy-Weisbach for calculations where you are solving for flowrate dischargevelocity, or diameter. The general form of the equation relates the mean velocity of water in a pipe with the geometric properties of the pipe and slope of the energy line. Velocity v cannot be determined from that nomograph you provided.

Hazen–Williams equation – Wikipedia

The variable C expresses the proportionality, but the value of C is not a constant. Am I using this method incorrectly? Register a new account. The Hazen—Williams equation has the advantage that the coefficient C is not a function of the Reynolds numberbut it has the disadvantage that it is only valid for water.

Already have an account? From Wikipedia, the free encyclopedia. Table of Hazen-Williams Coefficients. I just used the flow rates for each segment. The Hazen—Williams equation is an empirical relationship which relates the flow of water in a pipe with the physical properties of the pipe and the pressure drop caused by friction.

Using these methods would be a huge time saver, but is this a lost cause? Hazen-Williams Friction Loss Equation.

Hazen–Williams equation

However, the Hazen-Williams method is very popular, especially among civil engineers, since its friction coefficient C is not a function of velocity or pipe diameter. Share this post Link to post Share on other sites. More Discussion and References. Pipe Diameter, D ft: Posted January 30, Henri Pitot discovered that the velocity of a fluid was proportional to the square root of its head in the early 18th century.


Handbook of Hydraulics Seventh ed.

Pipe Flow Major Loss Calculator using Hazen-Williams Equation

Sign in Already have an account? Looking back, Nomograpph can get ‘close’ to the head loss using the chart I provided. Head Loss, h f ft: When used to calculate the pressure drop using the US customary units system, the equation is: I am trying to be very careful with my lines, but still – huge errors. My nokograph is that nomographs would probably be ‘closer’ for shorter pipe lenghts. The Darcy-Weisbach equation was difficult to use because the friction factor was difficult to nomograaph.

Research, and Software, Ltd. Archived from the original on 22 August I’ve tried to use http: Didn’t bother with velocities. Also, it does not account for the temperature or viscosity of the water. You have to be really careful with nomographs and other charts.