MS in Fire Protection Engineering
College of Engineering
Frederick Mowrer and Christopher Pascual
This report includes a fire protection and life safety analysis of the South Texas Project Turbine Generator Building (TGB). This analysis was done to fulfill the requirement for the Master of Science Degree in Fire Protection Engineering from California Polytechnic State University. The Turbine Generator Building consists of three elevations and is Type II-B construction. The TGB’s primary use is a special-purpose industrial building housing the turbine generator, main feed pumps, condensate pumps, condenser, feed water re-heaters, secondary cold chemistry lab, Balance-of-Plant (BOP) diesel, batteries, and switchgear, 13.8 kVA switchgear, and various other systems and components. This analysis consists of a prescriptive-based analysis and performance-based analysis.
The prescriptive-based analysis found that the egress and life safety, fire suppression, fire alarm, and structural fire protection features of the building meet the respective code requirements. The building was found to be compliant in the egress and life safety aspects and had adequate exits, exit separation, and travel distances. The building was found to meet the structural and building code requirements that come with the Type II-B construction but exceeds every allowable area factor except the non-sprinklered business. The TGB could be brought into compliance with IBC by providing sprinklers throughout and improving the fire resistance to meet Type II-A construction or by providing sprinklers throughout and providing frontage access to at least 50% of the building.
A performance-based analysis was conducted to evaluate the Turbine Generator Building by specifying fire safety objectives and determining if those objectives are achieved for specific fire hazards that could occur in the building. For the performance-based analysis three different design fire scenarios were modeled with calculations and analyzed using FDS.
The Design Fire #1 analysis consists of diesel fuel oil tank leak resulting in a pool fire in the BOP Diesel Room. The pool fire resulted in a fire that would likely achieve flashover and challenge the structural integrity of the space. It is recommended that additional fire proofing be added to the exposed crossmembers in the room, 2.25-inches of Vermiculite fire proofing would be sufficient for this design fire. A draining dyke around the diesel fuel oil tank would also minimize the surface area of diesel fuel, reducing the heat release rate of the resulting fire and the probability of flashover. A foam suppression system should also be considered to address the hazard.
The Design Fire #2 analysis consists of a high energy arc fault resulting in a switchgear fire that spreads to the spare breaker stored nearby. Design Fire #2 was shown to be a controllable event that did not challenge the structural integrity or personnel egress. Research has been conducted on the major concerns of this scenario, the high energy arc flash and the ignition of cables in cable trays, however the bridge between these two topics has not been evaluated. Determining if the HEAF could cause a cable tray fire was complicated by the lack of ignition temperatures for various cable types. This resulted in a scenario that didn’t evaluate this possibility and was limited to the nearby spare breaker. Further research on these topics could change the scenario modeled and provide better recommendations to improve the fire safety strategy.
The Design Fire #3 analysis consists of a seal oil leak at the hydrogen seal oil skid resulting in a pool fire inside the dyke. This pool fire would burn for approximately 99 minutes and fill the Turbine Generator Building with smoke and heat faster than occupants can safely evacuate but wouldn’t challenge the structural integrity of the building. The lack of a smoke control system results in the Available Safe Egress Time being less than the Required Safe Egress Time. Installing a smoke control system would be a traditional approach but a simpler method would be enclosing the HSOS to limit the effect on the TGB environment. Implementing a phased evacuation would also ensure personnel on the 55’ and 29’ elevations would be given priority since they’re exposed to the atmosphere immediately dangerous to life or health.