The Second Edition of the CCPS Guidelines for Pressure Relief and Effluent Handling was released recently, and we have finally had a chance to review the contents. Overall, the book has had a significant overhaul and expansion on key topics. Some highlights include:

• Expansion of techniques for analysis of reactive systems, including the use of adiabatic calorimetry and incorporation of many aspects of the DIERS Project Manual²
• Updates to sizing and installation calculations, including two-phase flow handling and updated equivalent velocity head factors
• Additional considerations for relief system installation, such as reaction forces
• Worked example problems, with a significant amount of text devoted to the mechanics of SuperChems™

Inglenook’s Aubry Shackelford worked with ProSaf’s John Hauser on the update of the first edition’s §3.3: Venting Requirements for Non-Reactive Cases, attempting to expand on the first edition’s techniques for required relief rate evaluations and source models, as well as reorganizing a bit. Unfortunately, it appears that the majority of updates ended up on the editing room floor. Since we believe that there is some value to these updates, which underwent internal and external review and comment periods, we will be providing the content of the previously proposed updates, along with additional commentary.

The proposed reorganization was focused on categorizing the estimation techniques, discussing the common calculation models, and providing details on venting (required relief rate) requirements. Nonreactive venting requirement estimation techniques can be broadly classified based on the cause for volumetric accumulation within the container – heating or cooling of a constant volume container, a volumetric excess of material flow into or out of the container, or a combination thereof.

The blogs in this series are outlined below, with links that will be updated as they are published. In the event the CCPS Guidelines 2nd edition is substantially equivalent, a reference to the guidelines is made instead.

• Heating or cooling of a constant volume container
• Calculation models
• Heat transfer characterization
• Fluid response without a phase change
• Fluid response with a phase change (see [1] p. 172-173)
• Relief requirements for single phase systems
• Relief requirements for two-phase systems without a phase change
• Relief requirements for boiling systems with complete disengagement (see [1] p. 173-174)
• Relief requirements for boiling systems with partial disengagement (see [1] p. 174)
• Relief requirements for boiling systems with homogeneous vessel venting (see [1] p. 174-178)
• Hydraulic expansion (see [1] p. 178; also see Fireside Chat – Hydraulic expansion pressure rise)
• Fire exposure (see [1] p. 178-186)
• Loss of heating / cooling control (see [1] p. 187)
• Excess inflow/outflow
• Calculation models
• Orifice flow
• Control valve flow
• Fluid driver throughput
• Pipe flow (see [1] p. 188, 321-349)
• Structural failure
• Heat exchanger tube failure
• Tube-failure characterization
• Steady-state calculation methodology
• Additional considerations
• Inlet control valve failure
• Inadvertent valve opening
• Material accumulation and heat input
• Unbalanced heat load
• Tank breathing
• Loss of agitation (see [1] p. 188-189)
• Mixing of hot and volatile materials (see [1] p. 189; also see Fireside Chat / Whitepaper – Mixing of hot and volatile fluilds)
• Rollover (see [1] p. 189)
• Additional techniques and considerations
• Specific code requirements (see [1] p. 190; also see Fireside Chat – Prescriptive requirements for overpressure protection in the US)
• Dynamic analysis