Gateway Arch

Preserving the Gateway Arch: Evaluating Fire Protection and Life Safety Conditions

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• published: 24 Sep 2015
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The preservation of a structure such as the Gateway Arch must include continuous re-evaluation of fire protection and life safety strategies. New materials or architectural configurations within the structure may represent an increased hazard over what was originally envisioned when the structure was designed and built, and new threats may develop that could have an impact on its use and preservation. Evaluation of a structure’s behavior in fire typically centers on impacts to occupant life safety. For a historically sensitive structure , such a study should also be concerned with property protection, either to minimize damage to the structure itself or to its culturally valuable contents and collections. Mills + Schnoering Architects and Hughes Associates, Inc. performed a fire/smoke modeling assessment of the Gateway Arch. This study provided input to answer the following questions and helped the NPS prioritize measures to provide a fire-safe environment for visitors and employees within the Arch: •If the modeling identifies deficiencies, what are the recommendations for physical changes and/or operational procedures? •If the modeling identifies risks to visitors, staff, and emergency responders, how can they be addressed? The fundamental goal of the study was to evaluate fire protection and life safety risks to the public and building occupants in the event of a fire or similar emergency, with emphasis on those occupants that may be located at the observation platform at the top of the Arch. The project’s primary fire safety goal was to provide an environment for occupants that is reasonably safe from fire and similar emergencies. An additional goal was to preserve historic or culturally significant building features. HAI reviewed existing conditions and past reports on the Arch’s structure and installed systems. Procedures employed at the Gateway Arch site were examined, including programs in place to train staff and information provided to visitors. These provided a detailed understanding of the current approach, exposed limitations, and identified resources currently available. Assessment of the fire environment at the Gateway Arch was a necessary component for evaluating life safety and egress during a fire emergency through a computational model. The fire environment is a transient condition represented by various exposures relative to the fire, including temperature, visibility, and toxicity in areas where occupants may be exposed. A digital model of the Arch was developed from the original drawings to provide three-dimensional input for computational modeling. A number of occupant movement scenarios were examined to assess conditions that arise under emergency situations. The observation platform and means of egress were modeled using EXODUS, an evacuation modeling software that simulates the movement of individual pedestrians under emergency and non-emergency conditions. The analysis highlighted and quantified areas that need to be addressed given the scenarios examined. Mitigation strategies were developed for several categories: •Fire Safety System Modifications •Structural Modifications •Procedural Modifications •Population Constraints •Training/Documentation Mitigation strategies were evaluated based on the results of the fire and egress analysis. Strategies were also evaluated for effectiveness, cost-effectiveness, and effects on the historical nature of the structure and facility operations.