Equivalent Length in Feet for Fittings and Valves

May 2 2022

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How to calculate equivalent length?

there is a simple mathematical expression for calculating the equivalent length of pipe fittings. It is the multiplied value of L eq /D by the diameter of the pipe. Where L eq stands for equivalent length (of the respective pipe) and D refers to the discharge of fluid.

What is equivalent pipe length method?

equivalent length of pipe 2 in terms of diam1 = Actual length of pipe 2 x (diam1 / diam2)^5. The following example illustrates this method. A pipe roughness of 0.05 mm is assumed (i.e. commercial steel). The flow direction is from the 100 mm section, through the reducer, and then through the 80 mm section.

What is the standard length of a pipe?

Single random pipe length is usually 18 – 25 feet plain end or 18 – 22 feet threaded and coupled pipes. Double random length pipes are made between 38 – 40 feet. The length of longer than double random pipes are more than 38 – 40 feet. Cut length pipes are made in fixed lengths within +/- 1/8 inch. Some pipes are available in about 80 ft lengths.

What is equivalent length of supply piping?

The present article gives Equivalent Length values for a wide variety of pipe fittings and valves that can be used as described in that article. The definition of the Equivalent Length of a pipe fitting is the length of pipe of the same size as the fitting that would give rise to the same pressure drop as the fitting.

How do you calculate equivalent length of pipe fittings?

If the valve is connected to 2″ Sch 40 steel pipe with an inside diameter of 0.172 ft (or 52.5 mm) then the Equivalent Length of the globe valve in terms of the steel pipe is 320 x 0.172 = 55 ft (or 320 x 52.5 = 16800 mm).

What does equivalent piping length mean?

Equivalent pipe length, EPL is a calculated numeric value that converts the friction losses associated with valves, bends, fittings and fluid velocities to a representative length of straight pipe of a stated type (metal, plastic, etc) and diameter.

How much length do pipe fittings add?

The length must include the distance between the fittings and the extra reach that goes into the fittings. If you are using 1/2-inch pipe, add 7/16 inch per end; and add 1/2 inch per end for 3/4-inch pipe.

What is the equivalent length of a 90 degree elbow?

Using the table of fittings and equivalent lengths above we find that the equivalent length for the 90° elbow is 12 pipe diameters.

How do you find equivalent lengths?

The equivalent length of piping that will cause the same head loss as a particular component can be determined by multiplying the value of Leq/D for that component by the diameter of the pipe. The higher the value of Leq/D, the longer the equivalent length of pipe.

What is meant by equivalent pipe?

An equivalent pipe is defined as the pipe of uniform diameter having loss of head and discharge equal to the loss of head and discharge of a compound pipe consisting of several pipes of different lengths and diameters.

How do you calculate fitting allowance?

2:354:19Fitting allowance for the piping trades – YouTubeYouTubeStart of suggested clipEnd of suggested clipSo the formula to find the fitting allowance is you take the face to center and you minus the threadMoreSo the formula to find the fitting allowance is you take the face to center and you minus the thread engagement.

How is pipe length measured?

To find it, measure around the circumference of the pipe with flexible measuring tape. Divide the circumference by pi, or about 3.14159. For example, if the circumference is 12.57 inches (319 mm), you would divide by pi, and get an outside diameter of about 4 inches (100 mm).

How do you calculate the length of a PVC pipe with fittings?

2:125:46How To Measure PVC Pipe-Measure Pipe And Fittings-Tutorial – YouTubeYouTubeStart of suggested clipEnd of suggested clipSo if i held the measuring tape in place right here. And i look directly down at the edge of the pvcMoreSo if i held the measuring tape in place right here. And i look directly down at the edge of the pvc. At the edge of the fitting right here it’s one and a half inches.

How do you calculate pipe bend length?

So, if the hose goes around a 90˚ bend, which is 1/4 of a full circumference, and the radius of the bend is R, then the length of the hose around the bend is = 1/4 x 2πR.

How many feet does an elbow add?

For example, each elbow used is equivalent to 30 feet of straight pipe or duct.

How is steel pipe length measured?

1:114:10How to measure NPT Fittings and pipe sizes – YouTubeYouTubeStart of suggested clipEnd of suggested clipPeople often wonder well what size is this can I put a ruler on there and figure it out and theMorePeople often wonder well what size is this can I put a ruler on there and figure it out and the answer is yes you can you take a roll. You put it on there.

What is equivalent length in fluid mechanics?

The equivalent length method (The Le/D method) allows the user to describe the pressure loss through an elbow or a fitting as a length of straight pipe. This method is based on the observation that the major losses are also proportional to the velocity head (v2/2g).

What is equivalent length of bar pendulum?

The bar pendulum consists of a metallic bar of about one meter long. A series of circular holes each of approximately 5 mm in diameter are made along the length of the bar.

What is equivalent length of compound pendulum?

The appropriate equivalent length for calculating the period of any such pendulum is the distance from the pivot to the center of oscillation.

What is equivalent length of column?

The equivalent or effective length is defined as the distance between two adjacent points of contra flexure on the column.

What is the equivalent length of a pipe?

The definition of the Equivalent Length of a pipe fitting is the length of pipe of the same size as the fitting that would give rise to the same pressure drop as the fitting . It has been found experimentally that for a given type of fitting (e.g. a long radius elbow) the Equivalent Length (L e) is larger for larger fittings. But it is found that if L e is divided by the inside diameter of the pipe (D) the ratio (L e /D) that is obtained is virtually constant for that type of fitting. This has 2 advantages – it dramatically decreases the amount of information that is required and it also removes the problem of the units used to measure lengths and diameters since the ratio L e /D is dimensionless. The tables of data in this article can therefore be used with any system of units, provided that the pipe inside diameter (D) and the Equivalent Length (L e) are measured in the same units.

How accurate is the equivalent length method?

The Equivalent Lengths in the Tables below can be expected to give accuracies of 50% or better. While this may sound extremely poor, it does at least give an indication of whether the pressure drop across the reducer is a significant portion of the overall pressure drop. This will give the engineer a basis on which to decide whether or not further work is justified or required to be able to come to a sufficiently accurate result. If better accuracy is required the more sophisticated methods as implemented in AioFlo should be considered. The Equivalent Length Method for reducers can only be used for turbulent flow (Reynolds Number > 4000).

How does a reducer work in steel pipe?

Steel pipe reducers are made with well rounded transitions between the straight and tapered portions. This significantly decreases the pressure drop when the reducer is used in the converging mode – i.e. with flow from the larger diameter towards the smaller diameter. Commonly available plastic reducers are not made this way. Plastic reducers generally have sharp corners between the straight and tapered portions, and the tapers are usually very steep. The Equivalent Lengths given below for plastic reducers are based on a sudden contraction. This may be a bit conservative, but in the absence of better data this gives a “safe” estimate. Equivalent Lengths are also given for sudden contractions in steel pipe and for smoothly rounded steel pipe reducers. The Equivalent Lengths in the Table below are based on the upstream diameter of the reducers.

Why is the pressure drop across a reducer not often modeled using the equivalent length method?

The pressure drop across a reducer is not often modeled using the Equivalent Length Method because reducers have 2 characteristic diameters. Also, the Equivalent Lengths for reducers are not as constant across changes in size and Reynolds Numbers as they are for the fittings listed in section 2 above. And of course the pressure drop through a reducer is different when the flow is from the large end to the small than it is with reverse flow.

How long is a 2″ globe valve?

As an example, consider a 2″ globe valve with L e /D = 320 when installed in commercial steel pipe. If the valve is connected to 2″ Sch 40 steel pipe with an inside diameter of 0.172 ft (or 52.5 mm) then the Equivalent Length of the globe valve in terms of the steel pipe is 320 x 0.172 = 55 ft (or 320 x 52.5 = 16800 mm).

What is the exponent of laminar flow?

In laminar flow the exponent used for calculating the ratio is 4 (in place of the 5 used above for turbulent flow).

Does the pressure drop in turbulent flow through pipes vary?

This method takes advantage of the fact that the pressure drop in turbulent flow through pipes varies inversely with the 5th power of the diameter, provided that the diameters are not too different. If the pressure drop through a pipe of a given length and of inside diameter diam1 is dp1, then the same flow rate through a pipe of the same length and of inside diameter diam2 will result in a pressure drop dp2, i.e.

Calculate minor pressure loss in piping systems with the Equivalent Pipe Length Method

An efficient and simple way to calculate the pressure loss in a piping system is the “Equivalent Pipe Length Method”.

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Citation

Engineering ToolBox, (2004). Equivalent Length Method – Minor Pressure Loss in Piping Systems. [online] Available at: https://www.engineeringtoolbox.com/equivalent-pipe-length-method-d_804.html [Accessed Day Mo. Year].

What is the equivalent length method?

The equivalent length method (L/D ratio) allows the user to describe the pressure drop through a fitting as a length of pipe. In theory the pressure drop through the fitting is equivalent to the pressure lost through a certain length of piping at that corresponding flow rate.

How many pipe diameters are in a 90 degree elbow?

Using the table of fittings and equivalent lengths above we find that the equivalent length for the 90° elbow is 12 pipe diameters.

What happens when the fittings size increases?

Typically as the fittings size increase the flow coefficient (L/D ratio) decreases, thus at pipe sizes larger than those at which the fittings equivalent length was determined the pressure drop will be over-estimated. At smaller pipe sizes than those at which the equivalent length was estimated the pressure drop will be under-estimated.

Definition

• The definition of the Equivalent Length of a pipe fitting is the length of pipe of the same size as the fitting that would give rise to the same pressure drop as the fitting. It has been found experimentally that for a given type of fitting (e.g. a long radius elbow) the Equivalent Length (Le) is larger for larger fittings. But it is found that if …

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