YMCA Building

Author

Tomas Lins, California Polytechnic State University, San Luis ObispoFollow

Date

6-2025

Degree Name

MS in Fire Protection Engineering

College

College of Engineering

Advisor

Frederick Mowrer and Christopher Pascual

Abstract

This project consists of the prescriptive and performance-based analysis of the fire protection and life safety features of the YMCA building in the city of Grants Pass, OR. The building was opened to the public in 1983 and was expanded in 2003. The initial construction is classified as Type IV and is not protected by a sprinkler system. The expanded section has a construction classification of Type II-B and is fully sprinklered. The main occupancies found in the building are Groups A and B. The building includes daycare room classified as Group E. The four core areas of prescriptive analysis were: structural fire protection, egress system, water-based fire suppression and control system and fire alarm and notification systems. The performance-based analysis focused on two fire scenarios: a workstation fire in the front desk and a fire in the daycare. The analysis of structural fire protection elements showed compliance with code requirements in all parameters evaluated. The areas classified as Group B require 1-hour fire separation from adjacent occupancies. That requirement was met with 1-hour walls separating Groups B and E and a 2-hour wall separating Groups B and A. The proximity with other constructions required 1-hour walls. The wall that’s adjacent to other small constructions in the vicinity of the YMCA building is rated for 2-hour fire resistance. Other parameters evaluated were building height, number of stories and building area. The egress analysis investigated the location and configuration of exit doors, exit access corridors and stairways, as well as the occupancy load for each area, floor and building total. The calculated egress capacity exceeded the requirements by a large margin, even with estimated occupancy loads much larger than the ones expected during normal operation of the building. The number of exits also met prescriptive requirements, as well as the separation of exits. Other requirements evaluated were dead- end corridors, common paths of travel, exit signs and handrails. The building was originally constructed without a sprinkler system. The expansion constructed in 2003, however, is protected by a wet-pipe system that extends to exit corridors and to other egress elements located on the original section of the building. The hydraulic calculations indicated a demand of 57.2 psi at a flow of 216.8 gpm at the BOR and 59.6 psi with a flow of 316.8 gpm at the POC. The supply at the POC was calculated to be 67.6 psi under the same flow (316.8 gpm), based on the measured static and residual pressures. Considering a 10% safety margin added to the city supply, the pressure at the POC was calculated to be 60.8 psi, still above the system demand but by a small difference. The prescriptive analysis of the fire alarm system evaluated the location, placement and coverage of initiating devices and notification appliances. The types of initiating devices found in the building were manual pull stations, smoke detectors, flow detector and heat detectors (sprinklers). Notification appliances were strobe lights, sounder/strobe and sprinkler alarm bell. Two areas were selected to assess light intensity compliance with NFPA 72, the gymnasium and the aerobics room. Both areas are protected by 110 cd strobe lights in the following configurations: 4 lights in the gymnasium and 1 light in the aerobics room. While the aerobics room met code standards, the lights in the gymnasium were found to be slightly underdimensioned and the use of 135 cd lights would satisfy light intensity requirements. Other characteristics investigated were wiring, power supply and ITM results and requirements. The performance-based analysis investigated the outcomes of two different fire scenarios. The first scenario was a large workstation fire near the main entrance of the building, with a peak HRR of nearly 7 MW. The second scenario was a smaller fire in the daycare (peak HRR 0.6 MW, approximately) that blocked the access to the exterior of the building, forcing occupants to use the exit access corridors in the interior of the building. Three tenability parameters were selected for this analysis: temperature, visibility and toxicity. The limits of tenability were defined as: temperature of 80 °C at a height of 1.8 m, visibility levels below 13 m and 4 meters, depending on the level of familiarity of occupants with the building and the fractional effective that would cause incapacitation in 50% of the population. The time to untenable conditions was evaluated by FDS models, which were also used to determine smoke detection time and sprinkler activation time. For both scenarios, untenable conditions first occurred due to limited visibility. In the workstation fire scenario, tenability limits were reached at 80 seconds for occupants considered to be unfamiliar with the building and 110 seconds for occupants considered to be familiar. On the daycare, the tenable limit was reached at 220 seconds when the door to the main exit corridor in the building was kept open and 171 seconds when the door was closed. The RSET was defined as the sum of detection time, alarm time, pre-movement time and movement time. Detection time and alarm time were estimated based on FDS results and code requirements. Pre-movement times were based on previous studies compiled in Tables 64.5, 64.9 and 64.11 of the SFPE Handbook. The determination of movement time was carried out by egress model simulations, created specifically for each scenario. The RSET for the first scenario was calculated to be 76 seconds and 85 seconds for occupants unfamiliar and familiar with the building, respectively. On the daycare, RSET was calculated to be 145 seconds. Time to untenable conditions and RSET were also estimated for egress elements in other parts of the building that were affected by the fires designed for both scenarios. The ASET was estimated to be 190 seconds on the exit walkway on the second floor and 220 seconds on the exit access corridor on the first floor. The RSET for these egress components was calculated to be 173 seconds for occupants evacuating through the walkway and 180 seconds for occupants evacuating though the exit corridors. In general, the investigation of the fire protection features of the YMCA building showed a high level of compliance with prescriptive requirements and this was reflected in the results of the performance-based analysis. ASET was found to be greater than RSET for all scenarios and locations in the building, with varying safety margins.