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ASHRAE Journal, July2008
Reducing Risk of Failures in Common Header Piping (Steel)
Use seamless steel pipe and fittings, all welded connections, no coped connections or saddle welds, no threaded or grooved joints until after the root valve.
this is the only restrictions i found
yes grooved fittings are now coming with a variety of machined rubber/ gasket with greater temperature range. Victaulic couplings with EHP gaskets are capable of taking -30 deg c to almost120 deg c temperature range.