PVC conduit thermal expansion calculator

Preliminary estimate

Inputs

Calculation note

This estimates movement only. Manufacturer expansion fitting data, supports, and installation instructions govern final layout.

Method

Movement mm = length m x temperature change C x 0.052

Absolute movement = absolute value of movement mm

Movement cm = movement mm / 10

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Formula variables

  • Length is the PVC conduit run length being reviewed.
  • Temperature change is the expected change in conduit temperature.
  • 0.052 mm/m/C is the coefficient used for preliminary PVC movement planning.
  • Movement magnitude helps decide whether manufacturer expansion fitting data must be reviewed.

Assumptions

  • The calculator uses 0.052 mm per metre per C as a common PVC expansion coefficient.
  • Positive temperature change means expansion; negative temperature change means contraction.
  • The output is movement only, not a complete support or fitting layout.
  • This calculator does not select expansion fittings, support spacing, conduit type, or installation method.

Examples

Outdoor run. 30 m of PVC with a 40 C temperature change estimates about 62.4 mm of movement.

Contraction check. A negative temperature change returns negative movement and the absolute movement magnitude for joint review.