I´m starting as irrigation contractor in South America. I'm aware that most literature advice to use Class 200 PVC for laterals. I would like to know why is this, since PVC pipe pressure rating already include an important security factor. Pipe manufacturers claim that you should not use a pipe rated more than 25% over design pressure values. So, if most of sprinkler systems have design pressures of 50-60 psi, why should we use Class 200 pipe ? Thanks a lot !
