Pipes and Temperature Expansion

Pipes expands when heated and contracts when cooled. The expansion of the pipes can be expressed with the expansion formula

The temperature expansion of pipes depends on the start and final temperature of the pipe and the expansion coefficient of the piping material at the actual temperature. The general expansion formula can be expressed as:

dl = α L_o dt (1)

where

dl = expansion (m, inch)

L_o = length of pipe (m, inch)

dt = temperature difference (^oC, ^oF)

α = linear expansion coefficient (m/m^oK, inch/inch^oF)

Mean expansion coefficient may vary with temperature as:

Formula (1) can also be used with SI units. The expansion coefficient must be adjusted to ^oC.

• T(^oC) = 5/9[T(^oF) - 32]
• 1 in (inch) = 25.4 mm
• 1 ft (foot) = 0.3048 m
• Expansion coefficients for some common materials

Example - Thermal Expansion of Heated Alloy Steel

100 feet of alloy steel pipe is heated from 32 to 212^oF. The expansion coefficient is 8 10^-6 (inch/inch^oF).

The expansion can be expressed as:

dl = (8 10^-6 in/in^oF)(100 feet) (12 in/ft) (212 - 32 ^oF)

= 1.728 inch

• Temperature Expansion of Pipes - Excel Template

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