Correction Due to Temperature | Taping Corrections | Surveying

Описание: When measuring or laying out distances, the standard temperature of the tape and the temperature of the tape at time of measurement are usually different. A difference in temperature will cause the tape to lengthen or shorten, so the measurement taken will not be exactly correct. A correction can be applied to the measured length to obtain the correct length.

The correction of the tape length due to change in temperature is given by:
𝐶_𝑡=𝛼Δ𝑇𝐿
where:
𝛼= coefficient of thermal expansion
Δ𝑇=difference in temperature at the time of measurement and the standard temperature
=𝑇_𝑚−𝑇_𝑠
𝐿= measured/laid out/nominal length

The correction {\displaystyle C_{t}}C_{t} is added to {\displaystyle L}L to obtain the corrected distance:

{\displaystyle d=L+C_{t}}{\displaystyle d=L+C_{t}}
For common tape measurements, the tape used is a steel tape with coefficient of thermal expansion C equal to 0.000,011,6 units per unit length per degree Celsius change. This means that the tape changes length by 1.16 mm per 10 m tape per 10 °C change from the standard temperature of the tape. For a 30 meter long tape with standard temperature of 20 °C used at 40 °C, the change in length is 7 mm over the length of the tape.