The steady-state techniques discussed in CCPS GPREH 2nd Edition §3.31 are usually conservative in nature when applied correctly. In general, some conservatism is desirable due to the variables involved in abnormal events that lead to…

A commonly encountered system involving both material accumulation and heat input is the low pressure tank. For fixed roof tanks, a vapor headspace is typically present above the residing liquid, and without credit for any…

The proper evaluation of some causes of overpressure for nonreactive systems involves consideration of both excess material entering/leaving the system and heat transfer within the system. Many causes of overpressure affecting distillation towers require this…

Considerations for inadvertent valve opening are similar to the inlet control valve failure; however, the calculation methodologies for pipe flow as described in CCPS GPREH 2nd Edition §4.41 are typically employed. Any normally closed valve…

A control valve on the inlet to the container that is connected to a high pressure reservoir can fail open to introduce excess material. The calculation methodologies described in Control valve flow are typically employed…

With the tube failure overpressure scenario deemed applicable and decision as to the geometry of the break made, an appropriate required relief rate calculation model can be chosen.1 Steady-state calculation methodology. These calculation models require…

The Tube failure characterization (CCPS GPREH2 trim) closed with the nine ISO 23251:2008 aspects that bear on the likely failure mode.1 The following evaluation criteria are recommended to help determine the effects that those aspects…

Tube failure in a shell-and-tube heat exchanger is the common structural-failure basis for overpressure protection.1 Before the relief load can be sized, the designer has to decide what kind of failure to design for. The…

The structural failure scenario is a special case of excess inflow.1 The method of estimating the flow through the break depends on the service and the specific type of equipment. After establishing the flow rate…

One of the flow limiting elements introduced in Excess inflow or outflow can be the fluid driver itself — the pump or compressor that establishes the maximum throughput available to the protected container at its…