1. At least since 2002 NFPA 25. Most likely much longer, but that's when I came into the sprinkler industry, so I'm not sure of the exact timing.
2. One percent of each sprinkler type installed, with a minimum of four sprinkler per sample. For multiple riser locations, I remove and test 1% of...
I don't have a suggestion for the expansion piping, but I can suggest Safety Kleen for glycerin and/or propylene glycol recycling. They charge approx $18 per gallon, so you have to add that into your pricing when recharging an antifreeze loop.
Randy
