Which of the following is considered a disadvantage of PVC pipe?

PVC pipe is known for its many advantages, yet it also has some disadvantages. Sensitivity to UV rays is one of these disadvantages. When PVC is exposed to sunlight over time, UV radiation can cause the material to degrade. This degradation may lead to brittleness, color fading, and a reduction in the structural integrity of the pipe. Therefore, if PVC pipes are used in outdoor applications or areas where they will be exposed to direct sunlight, they may require additional UV protection, such as paint or other coatings, to extend their service life.

The other provided options, such as corrosion resistance, heavy weight, and high melting point, do not represent disadvantages of PVC pipe. In fact, PVC is highly resistant to corrosion, lightweight compared to many other materials, and has a relatively high melting point, making it suitable for various applications.