What is the formula to calculate the weight of a pipe?

• A. 3.14 x D x Height x Thickness
• B. 3.14 x D x Height x Thickness x 40 = side weight
• C. Height x Thickness x 40
• D. 2 x 3.14 x D x Height x Thickness

Answer: (B)

We determine pipe weight by turning the wall volume into weight. For a thin-walled pipe, the wall volume is well approximated by the cross-sectional area of the wall (circumference times thickness) times the length. The circumference of a pipe is π times the outside diameter, so the wall volume ≈ π × D × t × L, where D is the outside diameter, t is the wall thickness, and L is the length (height). To convert that volume into weight, multiply by the material’s density. In the units used here, that density factor is 40, giving weight ≈ π × D × t × L × 40. This is why the formula includes 3.14 (π), the diameter, the thickness, the length, and the density factor, yielding the side weight of the pipe. The other options either omit the circumference, double it, or omit the density conversion, leading to incorrect results.