Date
6-2024
Degree Name
MS in Fire Protection Engineering
College
College of Engineering
Advisor
Frederick Mowrer and Christopher Pascual
Abstract
The purpose of this report is to practically apply the information conveyed in the Cal Poly Fire Protection Engineering Master of Science program by selecting a building and analyzing prescriptive and performance-based design features that accomplish the building’s life safety strategy. The selected building is the Goff Health Sciences and Technology Building located in Oak Ridge, Tennessee.
The Goff Health Sciences and Technology Building is a three-story educational facility with business, education, and assembly occupancies. The fire safety strategy of the building depends on a fire alarm communication system, wet pipe sprinkler system, structural fire protection components, and egress elements to protect and safely evacuate the building’s 1,289 occupants. Egress elements analyzed included occupancy classifications and characteristics, occupant loads, exit quantities, qualities and capacities, and regulatory requirements for egress systems. Other topics discussed included human behavior in fire, emergency movement, and toxicity analysis. The main compliance issues identified during the egress analysis were occupancy misclassification, inadequate exit signage, and fire barriers not extending far enough.
The Goff Health Sciences and Technology Building has a wide variety of components as a part of its complex fire alarm system. The principal component is the Simplex fire alarm control panel. The fire alarm system has many kinds of initiation devices including smoke and heat detectors, manual pull stations, duct detectors, and the integrated sprinkler system. These devices trigger both audible and visual notification devices used in the building, which include strobes, and combination horn-strobes. The installed mass notification system also functions as an emergency communications system. This fire alarm system has a dedicated primary power supply and a secondary power supply to keep it running at all times. Finally, a rigorous inspection, testing, and maintenance program is in place to ensure a constant state of readiness. With only a few exceptions, the Goff Health Sciences Building met code requirements, proving that it has effective fire detection, alarm, and communications systems.
The fire suppression system in the Goff Building consists of a single wet pipe sprinkler system adequately supplied by the City of Oak Ridge public water system. Different aspects of this sprinkler system include the riser and its associated components, the different kinds of sprinkler piping and heads located in the building, and how they are supported using hangers and seismic bracing. Hydraulic calculations were performed and evaluated, confirming that the city water supply meets the demand of the existing sprinkler system. Finally, inspection, testing, and maintenance requirements were laid out and compared to the known upkeep of the system. Issues identified include the hydraulic calculation sheet not being properly secured, a possible change in hazard classification in Room 245, an obstructed sprinkler head located in the 3rd- floor hallway, the unsprinklered spaces above the lower hallway ceilings, and the misapplication of window sprinklers on the interior stairwell glass. Also, significantly problematic was the lack of a robust IT&M program or at least a lack of documentation of activities performed.
The Goff Health Sciences Building is steel-framed, built with Type IIB construction that does not require many structural fire protection elements. A detailed analysis of the different structural and architectural components indicates that the Goff Building is well within the structural code requirements in place when it was built, with the exception of some of the fire barriers separating the vertical exit stairways.
A performance-based design approach was also used to evaluate the effectiveness of the Goff Building’s fire protection features. This was done by selecting specific performance criteria and using a comparison of Available Safe Egress Time (ASET) to Required Safe Egress Time (RSET) to determine if the building achieves its goal of life safety.
Design fire scenarios were presented to model when specific tenability limits are reached so a value for ASET can be assigned. Tenability limits were selected from Chapter 63 of the SFPE Handbook. They include a maximum allowable temperature of 121 °C and a smoke layer below 6 feet impinging on egress paths. The smoke criterion was selected for concerns of carbon monoxide poisoning and visibility reduction.
The first design fire selected occurs in a small office on the ground floor. The fire will initially start in a wastebasket and will proceed to ignite the contents of the room. The contents will be typical for an office space consisting of a desk, filing cabinet, computer, phone, a couple of chairs, and a reasonable amount of paper. It is assumed that the door has been left open. The technical justification for this fire is based on NFPA 101 “Design Fire Scenario 3”. This design fire would be directly across the hall from the largest lecture hall in the building. Regardless of whether the fire spreads into that space, a large fire coming out of the room would block egress out of the main emergency exit for the southeast wing. Additionally, a fire in this space would make access to the FACP in the adjacent electrical room difficult. With the compartment open to the hall, it was found to experience flashover conditions if no sprinkler activation occurs. This situation significantly affects both the egress and emergency communication aspects of the fire safety strategy.
The second design fire will occur in the main lobby on the first floor. The fire will start from a thrown cigarette and will ignite lobby furniture and spread to the other items in the space. This scenario assumes that the interior doors to both stairways are propped open. The technical justification for this design fire selection is based on NFPA 101 “Design Fire Scenario 2”. The special consideration for this fire determined that the smoke layer descended to the point that it hinders egress from the main level and the stairways. Calculations for temperature and smoke levels on the design fires were done using both manual methods and the Fire Dynamics Simulator (FDS) computational fluid dynamics (CFD) modeling program. They found that the Available Safe Egress Time to be approximately 4.7 minutes.
RSET was determined by summing together detection time, warning time, premovement time, and travel time. Detection and warning time are functions of the fire detection and alarm system within the Goff Building and were calculated using Zukoski plume correlations and FDS. Premovement was selected to be 74 seconds based on findings in a research paper about students in a 3-story educational building with similar occupant demographics. Emergency movement time for the Goff Building was calculated using the hydraulic model found in Chapter 59 of the SFPE Handbook. There are several assumptions made when using this model, including optimal use of exits, no interruptions in flow, and simultaneous beginning of egress. The model predicts total evacuation of the Goff Building in about 8 minutes.
For the proposed worst-case design fire scenarios, it was determined that RSET>ASET, demonstrating a weakness in the fire safety strategy, given the specific assumptions made. This fire safety evaluation for the Goff Building shows how much the fire safety strategy depends on the sprinkler system and stairways being maintained. The main recommendations for this report would be for the stairway fire resistance issues to be addressed and for the Emergency Management problems to be corrected, particularly regarding staff training and the upkeep of the sprinkler and alarm systems.
In conclusion, if the stairways and the sprinkler system function correctly, the Goff Health Sciences and Technology Building should be capable of accomplishing its fire safety strategy goal of life safety.
https://digitalcommons.calpoly.edu/fpe_rpt/180
Final Presentation