© Infrastructure Health & Safety Association (IHSA)
43 • Institute for Work & Health (IWH)
Example 3:
Calculate the weight of the steel pipe in kg.
The diameter is 3' 6".
The length is 12' 4".
The wall thickness is 7/8".
Step 1: Complete the calculation
Calculate the surface area of the pipe.
The pipe is a rolled up rectangle with the same length. The width is equal to
the circumference (π × d).
Convert inches to decimals of a foot.
3' 6" = 3.5'
12' 4" = 12.333'
Area = π × d × L
= 3.14 × 3.5' × 12.333'
= 135.53967 ft²
Note: 3.14 was used for π. If you use 3.14159 or the π button on the calculator, you will
get a slightly different answer.
Step 2: Locate the unit weight in Table 1.3 Weights of Materials (Based on Surface
Area).
Steel plate (per inch of thickness) = 40 lbs/ft²
