MS in Fire Protection Engineering
College of Engineering
Frederick Mowrer and Christopher Pascual
The purpose of the fire and life-safety analysis was to perform a prescriptive-based and performance based analysis on the fire and life safety systems in the Production Facility (PF) at Sandia National Laboratories (SNL). The prescriptive-based analysis determined if the building met applicable code requirements for existing life safety systems. The performance-based analysis consisted of a series of fire scenarios to ensure the fire and life safety systems allowed adequate egress time for occupants in the event of a fire. The prescriptive-based analysis was based on the Life Safety Code (LSC) and the International Building Code (IBC). The occupancy of each area was classified according to the use of the area and the hazards that exist. The applicable codes were used to determine if the life safety systems were appropriate for each occupancy classification. Life safety systems include: egress, fire suppression, fire alarm, and structural fire protection. The capacity of the egress system was calculated and compared to the occupant load. Analysis of the fire suppression system determined if the automatic sprinkler system was designed and installed to National Fire Protection Associate (NFPA) standards. The sprinkler water demand was calculated to ensure the water supply for the building was adequate. The fire alarm system was analyzed for proper spacing of detection and notification appliances. The electrical demand of the alarm system was calculated to ensure the battery backup supply was sufficient. The structural fire protection analysis confirmed proper materials and separation requirements existed in the building. The performance-based analysis used stakeholders’ goals and objectives to select appropriate fire scenarios to test the abilities of the installed fire protection systems. The first fire scenario was a kitchenette fire open to the main corridor with ineffective sprinklers. The second scenario was a kitchenette fire with the sprinklers active. The Society of Fire Protection Engineers (SFPE) hydraulic model, DETACT, and Pathfinder were used to calculate the required safe egress time (RSET). Fire Dynamics Simulator (FDS) was used to calculate the available safe egress time (ASET). A fire scenario was considered successful if the ASET was greater than the RSET. For the first scenario mentioned above (kitchenette fire-no sprinklers), the fire starts with the ignition of a microwave oven that subsequently causes a wood table and adjacent coffee maker to ignite and burn. During fire modeling simulations, it was found that after 66 seconds (ASET) the occupants would have to travel through a layer of smoke and hot gas in order to exit the building. Visibility was the most limiting condition, therefore the life safety criteria for this scenario was not met. For the second scenario (kitchenette fire with sprinklers), the fire starts exactly like the first scenario, except this time sprinklers activate and suppress the fire. During fire modeling stimulations, it was found that after 128 seconds (ASET) the occupants would have to travel through a layer of smoke and hot gas in order to get to the south exit. The exits are clear at 176 seconds (RSET). Due to the smoke layer height being at an acceptable level, this scenario was considered successful.
Recommendations for the aforementioned fire scenarios would be to keep exits clear, ensure sprinklers are operational, limit the amount of secondary combustibles in the kitchenette area, and replace suspect or malfunctioning appliances.