The zone where the variation of underground temperature is equal to zero
Application: In our daily life, we often need to bury the water pipe at a certain depth underground so that the waterproof pipe will break when exposed to the sun. In many cases, the water pipe is buried in the constant temperature layer, because the temperature of the constant temperature layer is relatively constant, which can prevent the water pipe from being damaged due to thermal expansion and cold contraction. Thus, the service life of the water pipe is prolonged.
- Chinese name
- Thermostatic layer
- Foreign name
- constant zone of subsurface temperature
- Thickness of constant temperature layer
- 40~80cm
constant zone of subsurface temperature
also called Normal temperature layer (normal temperature zone)。 Refers to underground temperature Is equal to zero zone 。 Thickness of constant temperature layer: 40~80cm, with an average thickness of 60cm.
It has Thermocline , below is Warming layer 。 [1] 
