Schedule 80 PVC (polyvinyl chloride) pipe is known for its increased thickness and strength compared to Schedule 40 PVC. It is designed to handle higher pressure applications. Generally, Schedule 80 PVC can handle pressures of around 250 to 280 pounds per square inch (PSI) at room temperature. However, it's essential to note that the maximum PSI capacity of Schedule 80 PVC can vary depending on factors such as pipe size, temperature, and the specific application. It's crucial to consult the manufacturer's specifications and guidelines for the specific Schedule 80 PVC pipe you plan to use, as they may provide precise PSI ratings for your intended use. Additionally, local building codes and regulations may dictate the allowable PSI for certain applications involving Schedule 80 PVC pipe.