Profile: Grinnell offers a single source for grooved piping products serving a wide variety of mechanical applications. Our manufacturing facilities ensure the standard of quality and testing on all products. We offer products like ductile iron & stainless steel couplings, fittings, grooved, check & butterfly valves, balancing valves, suction diffusers and strainers. Grooved fittings are rated at the pressure rating of the coupling being used. Grooved end pipe are available in nominal sizes of 1-1/4" (32mm) to 24" (600mm).