Steel Glazing Systems Protect from Fires and Evacuations

By JANE EMBURY

On June 27, 2012, London’s Corinthia Hotel was evacuated after fire broke out in an elevator shaft. The fire was quickly detected, and the hotel’s evacuation procedures worked smoothly. There was only limited damage, and nobody was hurt. This fire underlined how such shafts provide a ready pathway for smoke and fire to travel upward in multistory buildings. Buoyant fire gases in an elevator shaft can quickly fill upper floors, and there is much evidence to suggest that the majority of fatalities in such fires occur on higher floors that are significantly removed from the seat of the fire.

This was certainly true for the 1980 MGM Grand Hotel fire in Las Vegas, Nevada, which claimed 85 lives-the worst disaster in Nevada state history. Although this fire primarily damaged the second floor only, most of the deaths occurred on the upper floors, where elevator shafts and stairwells had allowed toxic smoke to spread.

Indeed, much of our understanding of the dynamics of vertical fire movement and how to deal with fires in tall buildings comes from the United States, the original home of the skyscraper. The first such fire, which entirely rewrote building regulations, was the Triangle Shirtwaist Factory fire in New York in 1911. It’s hard to overestimate the impact this fire had on both our understanding of vertical fire movement and on the building regulations that mitigate against fire risk. The fire in a garment factory in a tall building claimed 146 lives and directly led to new laws on building access and egress, fireproofing requirements, the availability of fire extinguishers, and the installation of alarm systems and automatic sprinklers.

Wrightstyle is a provider of integrated fire-rated steel and glass glazing systems for international markets, offering glazing systems designed to contain fire. We understand fire and how to deal with it. Our systems perform as if the elevator shaft were constructed as a solid wall. We offer an opportunity to safely open up these previously enclosed spaces, making the once functional shaft into an architectural feature. Only specialist glazing systems can achieve this as well as protect everywhere else in a building, from external curtain walling to internal fire screens and doors.

(1) A successful U.S. fire test, which involved the infamous hosestream test (only now used in the United States) that used a jet of water on the superheated structure to test for thermal weakness. (Photo courtesy of Wrightstyle Ltd.)

The basic rule in a fire situation has always been to avoid using elevators. However, as our understanding of fire dynamics has progressed, it is being rethought. For example, in Canary Wharf, at the heart of London’s financial district, the use of both elevators and emergency stairs in simultaneous evacuation exercises has significantly reduced evacuation times.

In the investigation into the World Trade Center (WTC) 2 collapse, it was found that in the 16 minutes before the impact of the second aircraft, 27 percent of those who evacuated used the elevators for part of their escape route. In addition, the investigation found some evidence that the flow rate from WTC 2 during these 16 minutes was approximately twice that for WTC 1, where only stairs were available for evacuation.

Fires involving elevator shafts pose particular risks in hotels where there can be large numbers of people, some of whom may be elderly or infirm and in an unfamiliar place. In 2007, an estimated one in 12 hotels and motels in the United States suffered a structural fire. Under current fire safety legislation, it is the responsibility of the persons responsible for the building to provide a fire safety risk assessment that includes an emergency evacuation plan for all people likely to be on the premises, including disabled people, and how that plan will be implemented. Such an evacuation plan should not rely on the intervention of the fire and rescue service to make it work.

Elevators can be friend or foe. Modern regulations require elevator shafts to be properly protected to ensure that any fire is contained within the shaft and not allowed to spread smoke and hot gases upward and into guest areas (which happened in Las Vegas).

Wrightstyle’s internal and external steel glazing systems have been tested together to United States and European standards and subjected to furnace temperatures of more than 1,000°C (1,832°F) to assess their overall capability of maintaining compartmentation in a fire. The core function of an integrated glass and framing system is to provide an effective barrier against the passage of fire, heat, and toxic gases and to prevent oxygen from reaching the seat of the fire, inhibiting its progress. This allows people to escape and, by containing the fire, minimizes fire damage.

JANE EMBURY is a director of Wrightstyle, the UK supplier of steel glazing systems. In the United States, Wrightstyle supplies through Hope’s Windows, Inc., a leading manufacturer of steel and bronze glazing systems.