Lawsuit against a pipeline company alleging that delivered gas to the facility was above the 7 lbs H2O/MMSCF specification. This caused the facilities regulators to freeze open which then resulted in over pressuring and rupturing of the downstream piping causing a fire and damage.
The first problem was that there was no downstream pressure protection (PSV) for this exact scenario. There was a pressure spec break (ANSI 600# upstream and ANSI 150# downstream) across the regulator. The argument was that they had two regulators in series and so it was double jeopardy for them both to fail. Anytime there is a pressure spec break there should be downstream pressure protection unless a HIPPs type of system is used. And this is not double jeopardy as a single cause, cold temperatures resulting in hydrates, could affect both regulators, which it did.
The second problem was that there was no inlet heater. So even at 3 lbs H2O/MMSCF hydrates would have formed during the cold temperatures experienced that day. Thus even with the supplied gas being below the 7 lbs H2O/MMSCF spec and within the contractual temperature limits, hydrates would still have formed and cause the problems experienced.
This was clearly a design bust that got overlooked. Our understanding of gas behavior and engineering principles helped another client prove their case.