Title

Prescriptive and Performance-Based Analysis of Colorado Liberal Arts College

Author

Victor Wight, California Polytechnic State University, San Luis ObispoFollow

Date

6-2022

Degree Name

MS in Fire Protection Engineering

College

College of Engineering

Advisor

Frederick Mowrer and Christopher Pascual

Abstract

This project consists of a prescriptive and performance-based analysis of an existing two-story college building. The building is located in downtown Colorado Springs, Colorado. Colorado Liberal Arts College is used for general education courses with the focus on creative fields such as dance, graphic design, and art. The building consists of classrooms, offices, an art gallery, dance studio, and a bookstore.

A prescriptive based design was completed using the code requirements laid out in the International Building Code (IBC) 2015 Edition and applicable National Fire Protection Association (NFPA) Codes. The prescriptive based analysis consisted of analyzing life safety and egress, fire alarm and notification, water-based suppression systems, and structural fire protection. The life safety and egress portions consisted of occupant load calculations, egress capacity, exit number and separation, travel distance, common path travel distance, dead end corridors, and exit sign design. All floors besides the south building second floor had sufficient egress capacity to account for all occupants. The second floor of the south building only has two unenclosed stairways that lead to exit discharges on the first floor and has an occupant load that exceeds the egress capacity by 54 occupants. There are three classrooms that only have one exit and exceeds the occupant number that would require these spaces to have more than one exit. One of these classrooms also has an improper door swing required for that space. Egress separation, travel distance, dead end corridors, exit sign location and common path of travel requirements are met per prescriptive requirements laid out by the International Building Code, 2015 Edition.

The buildings fire alarm and notification systems are installed in accordance with NFPA 72, National Fire Alarm and Signaling Code, 2019 Edition. The primary and secondary power supply meet the capacity requirements for the fire alarm devices, repeater panels, and control panel installed in this building. The voltage drop for the notification appliances do not exceed the capacity of the control panel or the repeater panels. The building is equipped with notification devices implemented and spaced in accordance with NFPA 72. There are duct detectors installed in HVAC ducts and photo electric smoke detectors installed in mechanical rooms, in front of elevators, and in front of fire alarm panels, however, most initiation is covered by sprinklers installed throughout the building.

The water-based fire suppression system in this building is installed in accordance with NFPA 13, Standard for the Installation of Sprinkler Systems, 2019 Edition. The building is split up into two zones, Zone 1 being the north building and Zone 2 being the south building. The breezeway connecting the north and south buildings is covered by Zone 2. The risers for the north and south buildings are in the basement located in the north building and is covered by the Zone 1 system. There are two hazard classifications in this building, light hazard, and ordinary hazard group 1. The most hydraulically demanding areas are in the north building. Both demands of a light hazard and an ordinary hazard group 1 design area were analyzed and fall under the supply curve which was reduced by 10% for a safety factor.

The building meets the requirements for a non-separated building in which the A-3 occupancy would have the most restrictive requirements. This most restrictive occupancy group governs the building height, area, and interior finishes in which the building meets the code requirements. The construction classification of type IIB ensures that structural members are noncombustible but not needing a fire resistance rating, which is in accordance with the International Building Code, 2015 edition. The only areas required to be fire rated are the elevator shafts and associated mechanical rooms. The fire dampers in these rooms did not meet the prescriptive requirements laid out in IBC 2015. The occupancy type, building construction type, sprinkler protection, and the number and type of openings on the exterior walls govern the fire separation distance in which this building is code compliant.

The goals of the performance-based design are outlined in NFPA 101, Life Safety Code, 2018 Edition. The goal is to protect the occupants not intimate with the initial fire development and to improve the survivability of occupants intimate with the initial fire development for the entire time it takes to evacuate the building. This is accomplished in this report by an ASET vs. RSET analysis. The Available Safe Egress Time (ASET) is established by performance criteria outlined in the Society of Fire Protection Engineers (SFPE) Handbook and NFPA 101. The performance criteria used for this analysis are visibility, temperature, toxicity, and smoke layer height to ensure occupants aren’t exposed to smoke or other toxic products from a fire. Three design fires were established, one in the north building and two in the south building. Design fire 1 is a classroom located on the first floor of the south building. Design fire 2 is a kitchen located on the second floor of the south building. Design fire 3 is an IT room located on the first floor of the north building. The design fires were established by standards laid out in NFPA 101 to simulate a typical fire for the occupancy which also considers occupant activities, number and location of occupants, room size, fuel properties, ignition sources, ventilation conditions, and where the initial fuel source is located. Fire Dynamics Simulator (FDS) and mathematical correlations were used to calculate when performance criteria were met, which establishes the ASET value. Establishing a Required Safe Egress Time (RSET) consists of detection time, notification time, pre-movement time, and movement time. The computer egress modeling software, Pathfinder, and an occupant egress hydraulic calculation outlined in the SFPE Handbook were used to establish the movement time which factored into the overall RSET equation. All fire scenarios considered both sprinkler activation and non-sprinkler activation which was done to provide data for a case where sprinkler system failure occurs.

In conclusion, the RSET exceeds the ASET in all design fire scenarios. The RSET exceeds the ASET by 315 seconds for design fire 1 when there is sprinkler activation and non-sprinkler activation. For design fire 2, the RSET exceeds the ASET by 68 seconds when there is sprinkler activation and 88 seconds when there is no sprinkler activation. Adjacent rooms to the room of fire origin were also analyzed in design fire 2 in which the RSET exceeds the ASET by 18 seconds. The RSET exceeds the ASET by 517 seconds for design fire 3 when there is sprinkler activation and non-sprinkler activation. Recommendations to remedy this would be to decrease the detection time by the installation of manual pull stations which would allow occupants to initiate evacuation when they see the fire instead of relying solely on sprinklers or initiation devices. Another recommendation would be to enclose and rate the stairwells to reduce smoke exposure to occupants traveling from the second floor to the first floor while exiting the building. A third method would be to decrease the pre-evacuation time by increasing staff and instructor training to initiate and assist with an evacuation as soon as notification is received.