## How to measure a steel pipe and calculating steel pipe weight

How to measure a steel pipe?

When people start measuring steel pipes, they may be confused. After all, pipe sizes range from 1/16 to 4, but these dimensions do not seem to match the actual dimensions of the steel pipe itself. In addition, the size of the male and female steel tubes are slightly different. In order to accurately measure any type of steel pipe, it is necessary to measure its OD (outer diameter) and compare it to the steel pipe size chart. Measuring Male Steel Pipes
Place the micrometer’s caliper on a part of the steel pipe and tighten it into the adjacent pipe.
Turn the micrometer screw until the caliper gently grips the tube.
Look at the sleeves of the micrometer and pay attention to the display of the measurement.
Open the water supply website. Find the measured value in column 2 in the chart. Position the thread (or pipe) directly to the right of the cell you just identified.

Measuring Female Steel Pipes
Place the micrometer’s caliper around the main part of the steel pipe.
Turn the micrometer screw until the caliper gently grips the steel pipe.
Look at the sleeves of the micrometer and pay attention to the display of the measurement.
The female pipe size is determined according to the steps of determining the size of the male pipe.

Tip
The male tube can be labeled “MPT” (male tube thread) and the female tube can be labeled “FPT” (female tube thread).
Warning
Do not determine the size of the steel pipe based on the number of threads per inch. There can be several different sizes, each with the same thread, so this method is not accurate.

How to calculating a steel pipe weight?

# Calculating Pipe Weight

## A weight calculating formula for steel pipes

### Weight of Empty Pipe

Weight of empty pipe per unit length can be calculated as

wp = ρm Am

= ρm π (do– di2) / 4

= (π / 4) ρm (do– di2)                               (4)

where

wp = weight of empty pipe per unit length (kg/m, lb/in)

ρm = density of pipe material (kg/m3, lb/in3)

Am = cross-sectional wall area of pipe (m2, in2)

do = outside diameter (m, in)

di = do – 2 t = inside diameter (m, in)

t = wall thickness (m, in)

### Weight of Liquid in Pipe

Weight of liquid in pipes per unit length can be calculated as

wl = ρl Ai

= ρl π (di / 2)2

= (π / 4) ρl di2                                    (5)

where

wl = weight of liquid in pipe per unit length of pipe (kg, lb)

Ai = cross-sectional inside area of pipe (m2, in2)

ρl = density of liquid (kg/m3, lb/in3)

• water content in pipes

### Weight of Pipe with Liquid

Weight of pipe with liquid can be calculated as

w = wp + wi

= ρm Am + ρl Ai

=  (ρm π (do– di2) / 4) + (ρl π di2 / 4)

= (π / 4) [ρm (do– di2) + ρl di2]                      (6)

• mass and weight – the difference

#### Weight of Pipe Calculator

This calculator can be used to calculate the weight of a pipe with – or without – liquid. The calculator is generic and can be used for both SI and Imperial units as long as the use of units are consistent.

do – outside diameter (m, in)

di – inside diameter (m, in)

ρm – density piping material (kg/m3, lb/in3)

ρl – density of liquid (kg/m3, lb/in3) (zero for empty pipe)

• 1 m = 103 mm
• 1 m2 = 106 mm2
• 1 in = 1/12 ft
• 1 in2 = 1/144 ft2
• 1 lb/in3 = 1728 lb/ft2

### Example – Weight of 4″ Schedule 40 Steel Pipe

The outside diameter  of 4″ Schedule 40 Steel Pipe is 4.500 inches. The wall thickness is 0.237 inches and the inside diameter is 4.026 in. The density of steel is 490 lb/ft3 (0.28 lb/in3). The weight per inch length of empty pipe can be calculated as

m = (π / 4) (0.28 lb/in3) ((4.500 in)2 – (4.026 in)2)

= 0.89 lb/in

= 10.7 lb/ft

### Example – Weight of 4″ Schedule 40 Steel Pipe with Water – SI Units

The outside diameter  of 4″ Schedule 40 Steel Pipe is 114.3 mm. The inside diameter is 102.3 mm. The density of steel is 7850 kg/m3. The density of water is 1000 kg/m3.  The weight per m length of pipe filled with water can be calculated as

m = (π / 4) [(7850 kg/m3)((0.1143 m)– (0.1023 m)2) + (1000 kg/m3) (0.1023 m)2]

= 26.3 kg/m

The weight of a steel pipe depends on the weight density of the material that composes the steel pipe as well as the physical volume of the steel pipe. Weight density measures the amount of compactness of the steel pipe material expressed in pounds per cubic foot.

The volume of a steel pipe equals its surface area times its thickness. Specifically, the surface area of a steel pipe is the same as a cylinder and equals the number of square inches that can cover the curved sides of the steel pipe. Measuring Wall thicknesss Measuring Flat oval pipe and Elliptic pipe size

Calculate the weight of round pipe and Special Section Tubes T.W.=(D-S)*S*24.65/1000 T.W.=((B+A)/2-S)*S*31.4)/1000 T.W.=12.33*(B+A-2S)*S/1000 T.W.=24.65*(1.1*SW+1.2*S)*S/1000 T.W.=(A-S)*S*31.4/1000 T.W.=[(24.65*(B-S))+(15.7*(A-B))*S]/1000 T.W.=[(A+(B/2*3.14))/2/2-S]*S*3.14 T.W.=24.65*(1.06*SW+1.11*S)*S/1000

Gather the necessary information. You will need to know the outside diameter of the steel pipe. This is the distance of a straight line that runs through the center of the steel pipe and connects two points on the steel pipe’s surface. You will also need to know the wall thickness of the steel pipe. Both of these measurements should be taken in inches. The final thing that you will need to know is the length of the steel pipe. This last measurement should be taken in feet.

Subtract the steel pipe’s wall thickness from the steel pipe’s outside diameter. For example, if you had a pipe with a diameter of six inches and a wall thickness of two inches, you would subtract two from six to get four.

Source: China Steel Pipe Manufacturer – Yaang Pipe Industry (www.steeljrv.com)

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)                    