Insert Fittings

[madpaddler]

I’m currently working with Rain Bird to design a new lawn irrigation system. The design parameters include a flow rate of 22 GPM at 60 PSI. Their recommendations includes an 1 ¼” Schedule 40 PVC main line with 1 ¼” poly laterals.
Living in WI, I'm concerned about potential problems with PCV joints due to soil movement and cold weather. For that reason, I/ve been thinking about using SIDR 11.5 160 PSI or SIDR 19 100 PSI for the main line instead. Seems most contractors around here use poly for main lines as well. I’ve compared the flow rates of PCV versus poly (poly actually flows better), but my questions is whether I need to concern myself with fitting size as I’d be using insert fittings with poly? PVC fitting ID is essentially the same as the pipe, while insert fittings for 1 ¼” poly is about 1.07” and 1 ½” poly is approximately 1.25”. Is the ID of the fitting a major concern?

 

[John Gayewski]

I’m currently working with Rain Bird to design a new lawn irrigation system. The design parameters include a flow rate of 22 GPM at 60 PSI. Their recommendations includes an 1 ¼” Schedule 40 PVC main line with 1 ¼” poly laterals.
Living in WI, I'm concerned about potential problems with PCV joints due to soil movement and cold weather. For that reason, I/ve been thinking about using SIDR 11.5 160 PSI or SIDR 19 100 PSI for the main line instead. Seems most contractors around here use poly for main lines as well. I’ve compared the flow rates of PCV versus poly (poly actually flows better), but my questions is whether I need to concern myself with fitting size as I’d be using insert fittings with poly? PVC fitting ID is essentially the same as the pipe, while insert fittings for 1 ¼” poly is about 1.07” and 1 ½” poly is approximately 1.25”. Is the ID of the fitting a major concern?

It depends on how close to the max design perameters you are. If 1.25" pvc is very close to the minimum size needed at the pressure recommended and your using a lot of fittings then it could effect performance. Mostly though systems are designed to work with any kind of pipe that is the right size. I would bet your gonna be fine unless your pump is undersized for the volume you need or your running a very large amount of pipe and fittings.