How do I find out the expansion and contraction rate of substrate(s)?
Expansion and contraction of materials is an important design consideration for external signs, particularly long fascia signs to shops, petrol filling stations etc. To determine the thermal expansion of any material it is first necessary to know the Coefficient of Thermal Expansion or Thermal Expansivity often expressed as 10-6 per oC. The coefficient for thermal expansion of aluminum is 24×10-6 per oC or 0.24mm per 10oC per M. For a south facing aluminum skinned sign within the UK an expected temperature range of 50oC is considered reasonable. Therefore given a 2.4m sign panel the expected expansion/contraction is (0.24×5)x2.4 = 2.88mm. For further information refer to BSGA Technical Guideline C2.5(c).
