Losing the Iron
Decommissioning the fire escapes on a landmark building
MANY URBAN CENTERS ARE UNDERGOING a renaissance involving the renovation of old or historic buildings that included fire escapes as part of their original construction. The renovations should be viewed as opportunities to improve both the buildings’ life safety and the safety and usability of the fire escapes. In some cases, that can mean getting rid of the fire escapes altogether.
An example of a building renovation that shed the original fire escapes was the Merchandise Mart project in Chicago in 1990–91. The Merchandise Mart has been a city landmark since 1930, a place where retailers could come to buy their wares all under one roof. Today, the building includes a mixture of office, retail, and assembly spaces. At 25 stories and covers two city blocks, it remains one of the largest buildings in the world, with 4.2 million square feet. Each floor typically encompasses about 192,000 square feet, with a calculated occupant load of about 1,875 people. “Postcard” photographs of the Merchandise Mart typically show the south side of the building along the Chicago River, never revealing the seven fire escapes originally included on the north facade of the building, which supplemented 15 interior stairways.
|
 |
Aerial photo of The Merchandise Mart
PHOTO: Corbis
|
|
Driven by the need to create a new public entrance on the north side of the building, improve life safety and aesthetics, and reduce the annual costs of inspections and maintenance, an extensive building renovation included removal of the fire escapes. Removal of fire escapes from a building typically requires approval of the local authorities, and such was the case in Chicago. Typical concerns included the number of exits from each floor based upon occupant load; exit capacity; exit travel distance; dead-end corridors; remoteness; exit enclosure continuity and fire resistance rating; and exit discharge.
In order to verify the adequacy of the building’s egress system without the fire escapes, an extensive survey was performed of the building. The survey revealed that there was inadequate exit capacity for the two upper floors (345 exit capacity vs. 601 occupant load, and 765 exit capacity vs. 1,150 occupant load), excessive exit travel distance on the same two floors (225 feet allowed vs. 265 feet actual), and a couple cases of excessive dead-end corridors. The survey also revealed a number of stairway fire doors that were either non-rated or for which a rating could not be proven.
After meeting with the owner and the design team, a remediation plan was established and a proposal was presented to the Chicago authorities. This plan included increasing the exit capacity of the interior stairways to 2,025 people on the typical floors, alteration of the corridor system to eliminate excessive exit travel distances (including the reduction of dead-end corridor lengths to code-complying distances), and restoration of rated exit enclosures by replacement of fire doors and repairs to rated walls. All of the improvements resulted in the building having an egress system in general compliance with the then-current Chicago Building Code. In addition, the owners committed to improvements to the sprinkler protection and occupant notification systems in the building as spaces were to be renovated. The plan was approved by the local authorities and the fire escapes were removed during the renovation.
Certainly, the scope and cost of this building renovation was large and atypical of most building renovations. As part of a move toward sustainable building and development practices, many buildings in urban centers are being renovated as an economic alternative to demolition and the construction of new buildings. Design professionals engaged in major renovation projects should be cognizant of the risks presented by fire escapes, even if they are technically code-complying features of a building. Major renovations should be viewed as opportunities to improve the level of safety by employing more acceptable means of egress, such as added or improved rated interior stairways, horizontal exits and, of course, active protection systems, being mindful of the nature of the occupants of the building and their specific needs.
Another recent project in Chicago involved a 24-story office building undergoing a major renovation. It had a single interior central stairway and several fire escapes located at the ends of the corridors. While code-complying as an existing building, the single stairway was considered an unacceptable risk because of the height of the building and the total number of people exposed in the event the stairway integrity was compromised. After much analysis, the owner decided to construct two new enclosed interior stairways and remove the fire escapes. This was at considerable expense. However, the nature of the occupancy and the risk perception by the owner dictated this course of action.
Carl F. Baldassarra, PE, is a principal with Wiss, Janney, Elstner Associates in Northbrook, Illinois.