Afterthoughts on Damages to the Tank

In specific extraordinary situations it may be necessary to temporarily increase the setpoint or bypass or deactivate some type of instrumentation or other equipment safeguard. However, this should only be done in an established manner, according to appropriate Management of Change procedures with proper approval. Furthermore, any special defeat to a safeguard should be properly signaled for the operators and documented in a special way. Operators and supervisors must regularly review that out-of-compliance log or alarm point summary so that the defeated system can be properly restored at the earliest possible time. 

Pipefitters Can Create Troubles When Reinstalling Relief Valves 

There have been reports of unique and improper SRV discharge piping on threaded safety relief. If the SRV discharge line runs horizontally and has a 90-degree ell mounted to provide a counter-clockwise thrust, then the SRV has spun and unthreaded their way out the connecting nozzle. 

Pipefitters have occasionally installed reverse buckling rupture discs upside down. Depending on the rupture disc manufacturer specifications, this usually means that the bursting pressure of the disc will be 50 percent higher than the manufacturer guaranteed as the relieving pressure. Such incidents must have happened at numerous plants and have been whispered about, but seldom documented. 

The simple error of installing a rupture disc upside down is easy to do in a minute or two and can jeopardize the integrity of the overpressure protection system. Rupture disk manufacturer s representatives are available to discuss proper rupture disk handling with engineers and craftsman. Such training can be very helpful. 

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