MS in Fire Protection Engineering
College of Engineering
Frederick Mowrer and Christopher Pascual
This report analyzes the impact of a fire located in the atrium at the Air National Guard Readiness Center (ANGRC) located at Joint Base Andrews, Maryland. The fifth floor is an enclosed penthouse used to enclose mechanical and electrical equipment. International Building Code (IBC) 2006 and 2005, section 506.1, excludes elevator penthouses of this type from the height and area calculations. The four occupied floors are used for office areas with the three- story atrium opening onto the balcony of the second- and the third-floor office area, and the second-floor conference center.
The prescriptive portion of this analysis looked at all fire and life system requirements, such as the fire alarm and detection system, mass notification, fire suppression, smoke management for the atrium, passive fire protection requirements, and life safety requirements for each intended occupancy. The Department of Defense (DOD) Unified Facilities Criteria (UFC), which takes precedence over the National Fire Protection Association (NFPA) and the International Code Council (IBC) requirements, was used for each of the main occupancies: business, concentrated use, assembly occupancy greater than 300 people, and associated small occupancy such as mechanical, electrical, and communication spaces. The atrium requires a smoke removal system to keep the smoke above the tenability requirements. The life safety code requirements for interior finish, travel distance, and dead-end corridors were all looked at part of the prescriptive analysis.
The performance-based portion of this analysis focused on the atrium with a fluid dynamic simulation (FDS) of the stage burning and the impacts to the smoke plume and movement impact to egress. A performance-based hydraulic model was used to evaluate the egress times available and required. This evaluation was conducted to determine Required Safe Egress Time (RSET) versus the Available Safe Egress Time (ASET) to ensure ample time was available within Margin of Time (MOT) safety factor. The ASET exceeds the RSET Time for the evacuation even with the increased occupant load.
Recommendations are to limit the materials used in the atrium to class A or B. While the UFC 3-600-01, Facilities Fire Protection Engineering simply requires compliance with NFPA 101, the more conservative approach is to follow the IBC for atrium interior finishes. Other recommendations would be to comply with the backup power requirement for the smoke control system. While the fire alarm has a backup battery system, the actual smoke removal system does not, and loss of power would impact the smoke layer for those evacuating during an event. While the stage is used intermittently in the atrium and risk is low, there is always the potential that must be considered.