All pipes and vessels expand and contract in direct proportion to a temperature change. This can be due to the temperature of the flowing media or from surrounding ambient temperature. Wind chill and solar gain are also factors that should be considered

Expansion and contraction can be calculated mathematically using the thermal expansion formula:-

X = L × (T1 -T2 ) × Cexp

Where

• X = Expansion or Contraction (m)
• L = Length of pipe or vessel (m)
• T1 = Starting Temperature (ºC)
• T2 = Final Temperature (ºC)
• Cexp = Coefficient of Thermal Expansion

Coefficients of Thermal Expansion for various common pipe materials are shown below:-

METALS PLASTICS
Materials Coefficient Materials Coefficient
Copper 16.4 x 10-6 ABS 100 x 10-6
Carbon Steel 12.2 x 10-6 UPVC 80 x 10-6
Stainless Steel (Austenitic) 16.3 x 10-6 CPVC 70 x 10-6
Stainless Steel (Ferritic) 10.9 x 10-6 PE 200 x 10-6
Cast Iron 11.0 x 10-6 PP 150 x 10-6

Expansion rates of common materials at various temperature changes are as follows:-

Temp change Rates of Thermal Expansion for Common Pipe Materials (mm/m)
ºC Copper C.Steel S.Steel Cast Iron ABS UPVC CPVC PE PP
10 0.16 0.12 0.16 0.11 1.00 0.80 0.70 2.00 1.50
20 0.33 0.24 0.33 0.22 2.00 1.60 1.40 4.00 3.00
30 0.49 0.37 0.49 0.33 3.00 2.40 2.10 6.00 4.50
40 0.66 0.49 0.65 0.44 4.00 3.20 2.80 8.00 6.00
50 0.82 0.61 0.82 0.55 5.00 4.00 3.50 10.00 7.50
60 0.98 0.73 0.98 0.66 6.00 4.80 4.20 12.00 9.00
70 1.15 0.85 1.14 0.77 - - 4.90 - 10.50
80 1.31 0.98 1.30 0.88 - - 5.60 - 12.00
90 1.48 1.10 1.47 0.99 - - - - -
100 1.64 1.22 1.63 1.10 - - - - -
110 1.80 1.34 1.79 1.21 - - - - -
120 1.97 1.46 1.96 1.32 - - - - -
130 2.13 1.59 2.12 1.43 - - - - -
140 2.30 1.71 2.28 1.54 - - - - -
150 2.46 1.83 2.45 1.65 - - - - -
160 2.62 1.95 2.61 - - - - - -
170 2.79 2.07 2.77 - - - - - -
180 2.95 2.20 2.93 - - - - - -
190 3.12 2.32 3.10 - - - - - -
200 3.28 2.44 3.26 - - - - - -
210 - 2.56 3.42 - - - - - -
220 - 2.68 3.59 - - - - - -
230 - 2.81 3.75 - - - - - -
240 - 2.93 3.91 - - - - - -
250 - 3.05 4.08 - - - - - -
260 - 3.17 4.24 - - - - - -
270 - 3.29 4.40 - - - - - -
280 - 3.42 4.56 - - - - - -
290 - 3.54 4.73 - - - - - -
300 - 3.66 4.89 - - - - - -