MS in Fire Protection Engineering
College of Engineering
Frederick Mowrer and Christopher Pascual
A fire and life safety analysis was performed in fulfillment of one of the requirements for the Master of Science Degree in Fire Protection Engineering from California Polytechnic State University San Luis Obispo (Cal Poly). The analysis consisted of a prescriptive and a performance-based analysis. These analyses were performed on Building 171A which is part of the Cal Poly San Luis Obispo campus. The prescriptive analysis consisted of four distinct areas of focus: 1) Structural Fire Protection, 2) Water-Based Suppression Systems, 3) Fire Alarm and Detection Systems, 4) Egress Analysis and Design Prescriptive analyses are performed to determine whether a building conforms to the applicable codes and standards. The prescriptive analysis of Building 171A was undertaken using the 2016 editions of the California Building Code (CBC) and California Fire Code (CFC), and the most recent editions of various National Fire Protection Association (NFPA) codes. No deficiencies were encountered in the structural fire protection, water-based suppression systems, fire alarm and detection systems, or the egress design of Building 171A. Information required to establish code compliance beyond all doubt was occasionally not available. In such cases, it was assumed the system or systems were arranged in such a way as to be compliant else the building plans would not have been approved. This analysis determined Building 171A to be in compliance with code requirements. Performance-based analyses are used to establish the functionality of a building’s fire protection strategy by using performance criteria that demonstrate compliance with design goals. Because of the residential nature of Building 171A, the ability of occupants to evacuate safely was assessed. Two viable fire scenarios specific to Building 171A were evaluated using Fire Dynamics Simulator (FDS) and Pathfinder. The first design fire was modeled as an arson fire on the second floor of the central stairway. For this fire, a commonly used liquid accelerant was assumed. The fuel was treated as a pool fire with no growth phase. Physical properties like soot and carbon monoxide yield from the Society of Fire Protection Engineers (SFPE) Handbook were entered into the model to increase the accuracy of results. Tenability criteria were not exceeded at any point during the simulation for this design fire. Therefore the available safe egress time (ASET) was greater than the model run time of 600 seconds. The second design fire was modeled as a furniture fire in the study room on the second floor. This fire was assumed to initiate in an armchair. Exact materials could not be determined however the individual component materials must result in an item that as a whole complies with California Technical Bulletin 133 (CTB 133). Calculations for this fire were based on a fast αt2 fire with a maximum heat release rate of 80 kW. The predominant material was assumed to be flexible polyurethane foam with the worst carbon monoxide and soot yields. From SFPE Handbook tables, this was determined to be GM27 polyurethane. The tenability criteria monitored for the duration of the simulation were not exceeded at any point for this design fire. Therefore the ASET was greater than the model run time of 600 seconds. Occupant characteristics were entered into Pathfinder, an agent-based egress modeling program, to determine the required safe egress time (RSET). A pre-movement time was incorporated into the model encompassing detection, alarm activation, and occupant response time. In consideration of the wide variability of occupants’ responses, a factor of safety of 1.5 was also included. The RSET for the Central Stairway and Study Room fires was calculated to be 440 and 490 seconds, respectively. This is considerably less than the ASET since tenability did not fail within the 600 seconds of model run time. Therefore both fire scenarios had RSET values less than ASET values indicating that passive and active fire protection systems in Building 171A would enable occupants to safely evacuate.