You absolutely, positively should NOT use Victaulic piping in category M (lethal) service, even at 2 barg pressure! Most people shy away from using Victaulic in anything other than Category D (nonhazardous fluid) services. The main concern is fire safety of the design, given the huge amount of rubber gasket material in each joint, but there are other concerns. It is widely used for Category D services such as potable and fire suppression water, compressed air and nitrogen etc. It has a very limited upper service temperature due to the performance of the rubber gasketing and is not recommended for steam or condensate at any pressure above atmospheric.
Grayloc is a replacement for something like a metallic ring-type joint flange at classes 1500# and above. It offers very significant fire safety, but it can be leakage prone at low pressures and merely tightening the clamp bolts may not stop the leakage. The sealing ring in Grayloc is energized by internal pressure, rather like an o-ring. Using it at 2 barg is a bit like swatting a fly with a sledgehammer, but it is allowed in category M. You'd be served better by using 150# ASME B16.5 flanges with a suitable gasket material in my opinion. If you use a spiral wound gasket with graphite filler, assuming it is acceptable for your service conditions, the resulting joint will likely be more than adequate from a fire safety perspective.
Can you use them Cat M?
