PVC (polyvinyl chloride) pipes are one of the most widely used types of polymer pipes in the construction, water supply and sewage industries. However, their use is not recommended for the transport of hot fluids. According to experts, including those from Polymer Pars Company, the thermal limitation of PVC is one of the most important factors in the correct selection of this product.
Technical reasons for not recommending the use of PVC for hot fluids
1-Reduction in mechanical strength at high temperatures
As temperatures increase, the molecular structure of PVC softens and its tensile and compressive strength decreases. This can lead to deformation or even cracking of the pipe.
2-Increase in creep
At high temperatures and under pressure, PVC creeps; that is, it permanently deforms over time.
3- Decreased work stress tolerance
As the temperature increases, the pressure that the pipe can withstand decreases. Therefore, in hot water transmission systems, the risk of leaks or bursting of the pipe increases.
4-Changing chemical properties
High temperatures can accelerate the thermal degradation process and reduce the useful life of the pipe.
What is the upper limit of PVC working temperature?
The maximum continuous operating temperature for rigid PVC (uPVC) is typically 60°C (140°F).
Some sources consider 70°C to be acceptable for short-term use, but it is not recommended for continuous operation.
Where higher temperature fluids are required, CPVC is commonly used, which can withstand temperatures up to about 90°C.
Conclusion
The use of PVC for the transport of hot fluids is not recommended due to reduced mechanical strength, increased creep, and reduced pressure tolerance. The correct selection of pipe type based on operating temperature plays an important role in increasing the safety and longevity of the piping system.