MS in Fire Protection Engineering
College of Engineering
Frederick Mowrer and Christopher Pascual
A fire and life safety analysis was completed for Building V as part of a culminating project in the California Polytechnic State University at San Luis Obispo Fire Protection Engineering Master’s Degree Program. This report will detail both a prescriptive design based on the 2013 California Building Code and applicable standards as well as a performance based analysis based on a design fire scenario.
The prescriptive design will discuss four main components of compliance: 1) Structural Fire Protection, 2) Fire Alarm, 3) Fire Sprinkler, and 4) Means of Egress. Structural fire protection analysis is separated into four parts: type of construction, structural fire resistance, fire resistance separations, and flammability are reviewed. Building V was constructed as a Type IB structure and met all requirements for area and height. Protecting the structural members with 1-and 2-hour fire ratings were also compliant for Type IB construction. The required separations for shafts and uses were also properly designed with 1-and 2-hour fire protected separations. Lastly, flammability of interior finish materials was limited by using Class A products only.
The fire alarm system analysis is broken up into six areas: fire alarm types, initiating devices, notification devices, fire alarm system design, smoke control, and inspection, testing, and maintenance. Building V was properly provided with a manual fire alarm with automatic smoke detection and an emergency voice/alarm communication system as required by code. The initiating and notification devices were provided in proper locations with compliant spacing. The fire alarm system was also designed properly for operating in an emergency condition without building power. Required compartmentation for smoke control was met with the use of automatic closing doors and fire/smoke dampers. Lastly, proper inspection, testing, and maintenance will ensure that the building maintains a functional fire alarm system.
The fire sprinkler system analysis is also divided into six areas: fire sprinkler type, standpipe type, fire sprinkler design criteria, hydraulic calculations, sprinkler components, and inspection, testing, and maintenance. A wet automatic sprinkler system was installed per NFPA-13 as required by code. Class I standpipes were installed within all interior exit stairs as well. Each area was analyzed for their occupancy group hazard and was found to provide enough water for the demand of the sprinkler system. Lastly, proper inspection, testing, and maintenance will ensure that the building maintains a functional fire sprinkler system.
The last portion of the prescriptive design analyzed the means of egress of the building. An occupant load calculation was used to determine the required number of exit access doorways, the required exit access and stair widths, travel distances, common paths of egress, and dead ends. Once the exit access was analyzed, the required number of exits and required exit width was found. The building was found to be fully compliant with means of egress as required by Chapter 10 of the California Building Code. Occupants would be able to safely egress to the public way.
The performance based design analyzed a design fire scenario of a couch within the corridor. The couch was assumed to be a composite of flexible polyurethane and cellulose material. An analysis of required safe egress time (RSET) and available safe egress time (ASET) was completed to determine if occupants would be able to safely evacuate the building in the case of a fire. The ASET was calculated based on three tenability criteria of visibility, temperature, and carbon monoxide concentration. All conditions were analyzed at six feet above the walking surface. In order to maintain tenable conditions, visibility could not be reduced to less than 33 feet, temperature needed to be less than 176o F, and carbon monoxide concentrations had to be less than 1,000 ppm. The design fire scenario was modeled using Pyrosim and time to reach untenable conditions were found. Based on the results, visibility was reduced to less than 33 feet within 120 seconds of the start of the fire. Temperature exceeded 176o F within 180 seconds of the start of the fire. Lastly, toxicity was able to be maintained at less than 1,000 ppm CO during the duration of the simulation.
The RSET was calculated based on three movement time frames: detection time, pre-evacuation time, and travel time. Detection time was calculated using a Detact model and found that sprinkler activation occurred within 117 seconds of the fire being started. The pre-evacuation time was based on data collected in research in which an average of 186 seconds was found for a mid-rise apartment with good alarm performance. Lastly, the travel time was modeled using Pathfinder to determine the required time to safely egress the building. The travel time was found to be 213 seconds. The occupants would need 516 seconds to safely evacuate the building before the effects of the fire would have made conditions untenable for evacuation.
Based on the design report, two recommendations would be made to help maintain a safe environment for the occupants of the building. The first recommendation would be to remove the furniture within the rated corridor and limit the use to circulation only. A second alternative recommendation would be to create an enclosed room for the alcove and provide a rated separation between the lounge area and the rated corridor.