Determining the optimal pipe size and material for an irrigation system involves considering factors such as flow rate, pressure, and friction loss. Pipe size must be sufficient to handle the required flow rate without excessive pressure loss, which can lead to reduced system performance and increased energy consumption. Pipe material selection depends on factors such as corrosion resistance, durability, and cost. Common pipe materials used in irrigation systems include PVC, HDPE, and ductile iron. It’s essential to consult with a qualified engineer or designer to ensure the pipe size and material selection meet the system’s specific requirements.