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the home of .TT pocketEngineer softDesign - where pocketEngineer software lives...
 Pipe_f.Loss v1.3 (Windows)

a single pipe friction loss (pressure drop) calculations... featuring 2-K Method minor loss



To take a glance at all pocketEngineer software and OS requirements, click Overview.



 Pipe_f.Loss: Full built-in Data, Material & Fitting Selections  

Pipe_f.Loss is specially developed to feature 2-K Method for a single pipe friction loss (pressure drop) calculations. Note that Pipe_f.Loss does not calculate total system (pump) head.

It's a plug-and-use Windows PC program, thus creating a mobile design environment (
ShowMe!) for the practising engineers & designers in today's mobile world.



- built-in selections for valves & fittings losses using 2-K Method developed by Hooper
- 4 options (Colebrook, Swamee, etc) for solving friction factor f
- design as easy as "Select
& Click" with full built-in database, conversion calculators, guides, etc
save/open project, save results to Rich Text File (.rtf) for formatting & printing

- fully mobile “plug-and-use” program with no setup requirement

- in SI & IP units


                    features 2-K Method           in SI & IP units              view Pipe_f.Loss explained



 Feature . . . 2-K Method for Minor Loss Calculations 

The 2-K method is a technique developed by Hooper B.W. to predict the head loss in an elbow, valve or tee. The 2-K method is advantageous over other method especially in the laminar flow region. The 2-K method takes the following forms of equation:

a) for valve & fitting
K = (K1/Re) + K2(1+(1/ID))

K1 = K for the fitting at Re (Reynolds number) = 1, laminar flow 
K2 = K for a large fitting at Re = infinity, turbulent flow
ID = internal pipe diameter in inch

for entrances & exits
,  K = (K1/Re)+K2. Here, the constant K2 is the "classic" K.

for details, refer to (1) "The Two-K Method Predicts Head Losses in Pipe Fittings" by Hooper B.W.,  Chemical Engineering, August 24, 1981; (2) "Fluid Flow Handbook" by Jamal M. Saleh (Editor), McGraw-Hill, 2002

A calculation example using 2-K method can be
downloaded here.


Solver for solving Friction Factor, f  . . . don't be confused 

note: The friction factor, f, mentioned here is Darcy friction factor, not Fanning friction factor. Darcy f = 4 x Fanning f - don't be confused!

Laminar Flow: Friction factor is solved by the equation f = 64/Re, where Re=Reynolds number.

b) Turbulent Flow: Solving friction factor for turbulent flow can be tedious and complex. There are numerous equations, both implicit & explicit forms, available for solving friction factor.


Implicit equation requires iteration process and it is best to let a computer program to perform it. The most popular and common one is the Colebrook equation. However, it is to note that there are numerous forms of Colebrook equation available - main and modified forms. In the Pipe_f.Loss program, 4 friction factor equations are included as follows:





 Head Loss & Pressure Drop: Darcy-Weisbach equation 


Darcy-Weisbach equation is used in the head loss and pressure drop calculations. For details, refer to ASHRAE Fundamentals 2005.


Note: For multiple Series pipe with a loop ring main on Windows, see easy Pipe Friction (ePF) Loop (Windows).


 Calculation Example: 2-K Method Minor Losses  (in English units)

Consider a 16-in (ID = 15.624-in) Sch 40S stainless steel system. The system contains 100 ft of pipe, 6 long-radius (R/D=1.5) 90o elbows, 2 side-outlet tees, 2 gate valves (β=0.9) and an exit into a tank. The fluid has dynamic viscosity of 1 cP, density of 62.43 lb/ft³, and the flow rate is 13.314 ft³/s. What is the head loss through this system?


The following is the results computed by Pipe_f.Loss program:


Pipe friction Loss  calculations





Fluid Data

Fluid = Water @ 20 °C (68 °F)

Density, ρ = 62.43 lb/ft³

Dynamic viscosity, µ = 1 cP = 0.000672 lb/ft.s

Kinematic viscosity, v = 1.08E-05 ft²/s

Flow rate, Q = 13.314 ft³/s

Mass flowrate, q = 831.19 lb/s




Pipe Data

Material = Stainless Steel

Roughness, ε = 5E-05 ft

Relative roughness, ε/D = 3.84E-05

Diameter, D = 15.624 in

Length, L = 100.00 ft

Flow Area, A = 1.3314 ft²

Velocity, V = 9.9998 ft/s



Friction Factor

Reynolds nos, Re = 1,209,624

Flow regime = Turbulent

Friction factor, ƒ = 0.012192 - solved by Swamee (Explicit Eqn 2)


Minor Losses

<Valves & Fittings>

Qty=6       K1=800    K∞=0.2     Elbows, 90, Long-radius(R/D=1.5), all types

Qty=2       K1=800    K∞=0.8    Tees, Used as elbow, Standard, flanged/welded

Qty=2       K1=500    K∞=0.15   Valves, Gate/Ball/Plug, Reduced trim, B=0.9

Total Kf = 3.305


<Entrance & Exit>

Qty=1       K1=0        K∞=1        Exit, projecting / sharp-edged / rounded

Total Ke = 1.000


Head Loss and Pressure Drop

Head loss for Pipe, ΔHp = 1.455 ft (K = 0.936)

Head loss for Minor losses, ΔHm = 6.687 ft

Total Head loss , ΔH = 8.142 ft

Total Pressure drop, ΔP = 3.53 psi (0.243 bar)                                                                                   





Compare the above results with  Hazen-Williams and Darcy-Weisbach equations with equivalent length Le and resistance coefficient K method . . . on Android.




For multiple Series pipes + loop ring main pipe network, see  ePF Loop (easy Pipe Friction) on Windows.




eXperience yourself

the mobile "plug-and-use" 

Pipe_f.Loss program

Price: USD 9.90


Download now:

product detail 


OS requirements: Windows.


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