[Cob] Radiant heat floors

[Deanne]

Apologies in advance if this has already been answered in recent memory.  I would like to use radiant heat in the house I'm (still!) designing, and have not been able to locate information about how long the tubing used in radiant heating lasts.  
   
  Since it's all embedded in concrete (or can something else be used?) what do you do if/when there's a break or other deterioration of the tubes?  I'm wondering about the fluid that conducts the heat absorbing into the concrete, and how to plan for replacing any damaged tubing.
   
  Thanks,
   
  Deanne