Expansion and contraction of PVC pipe is a common concern, and the issue applies to all lengths of pipe, not just those over 100 feet.According to the chart you mentioned, a 4" PVC pipe that is 50 feet long will experience a temperature change of 2.03 inches at 100 degrees Fahrenheit. This means that the pipe will expand by 2.03 inches when the temperature increases by 100 degrees Fahrenheit.To accommodate this expansion, you would need to install one expansion fitting. Expansion fittings allow the pipe to move freely without causing damage to the pipe or the fittings.It is important to note that the actual amount of expansion or contraction will vary depending on the specific type of PVC pipe you are using. Some types of PVC pipe have a higher coefficient of thermal expansion than others.Here is a general rule of thumb for determining the number of expansion fittings needed for a given length of PVC pipe: For lengths up to 100 feet, one expansion fitting is sufficient. For lengths between 100 and 200 feet, two expansion fittings are recommended.* For lengths over 200 feet, three or more expansion fittings may be necessary.It is always best to consult with the manufacturer of the PVC pipe you are using to determine the specific number of expansion fittings required for your application. Flag for review