i guess aluminum pipe insulation covers were just to expensive that day.
Yep. Also, notice that they ran the PVC pipe to the opposite side of the chiller and then back to the side where the pipes come through the roof instead of running a straight run. Steel pipe came through the roof and then transitioned to PVC right where the pipe penetrated the roof. Also, they have some 4" sections, and some 3"sections of pipe. It should all be 4".