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How to Count Weld Inches

How to Count Weld Inches - Calculate Man Hours Calculate man Hours. How to count weld inches.
In this post, we explore the concept of how to quantify the number of inches of welding in piping.

Weld’s Diameter Inch Count

The number of inches-diameters for a particular piping system is obtained by multiplying the dimension of the joints by the number of joints of this diameter.


In this case, we will calculate the welding inches over a length of piping, using the following picture from the book “Estimator’s Piping Man-hours Tool”.

Calculate Man Hours - Estimator's Piping Man-hours Tool"

How many inches of weld?

The figure above represents the piping portion of a pump discharge.

The above section, starts from the discharge flange (2 1/2″ diameter) of a centrifugal pump and then, through a 2 1/2″ x 4″ concentric reducer, connects to a 4″ diameter pipe that terminates in a 6″ NPS manifold.

To count the number of inches welds are computed according to the following table.

Calculate Man Hours - Table

We note that to count the number of inches of welds, only the diameters of the pipe parts we weld are taken into consideration.


The times used to weld a certain number of inches across a line are only valid for that line and site.

Keep in mind that the welding times for the same diameter-inch number are different from:

Piping of different diameter.

The welding times of four 4-inch butt joints are not the same as those required for one 16-inch joint.

Piping of different Schedule.

Welding a Sch 80 end-to-end joint takes more time than welding a Sch 40 joint with the same diameter.

Piping of different material

They have different soldering methods.

Different kinds of joints to weld

The time it takes to weld a butt seam is different from the time it takes to weld a socket weld, etc.)

Different quality control systems

Different environmental conditions, and so on.

In the following article, we will talk about how making pipe spool.

Calculate Man Hours


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