Consulting-Specifying Engineer - March 2009 - (Page 38) Viva Las Vegas A recent high-rise hotel fire in Las Vegas has many eerie similarities to the Joelma Building fire. The fire occurred at 5 p.m. on July 14, 2008, in the Bally’s Las Vegas Hotel & Casino, which is a 26-story reinforced concrete structure. The hotel was built in 1972 to 1973 and has 2,000 guestrooms. The building has three wings built in a T-shape with one interior and one exterior stairwell at each wing. The Bally’s building is the same structure that was originally involved in the 1980 MGM Grand Hotel fire. In that fire, an electrical fire in the first-floor delicatessen spread quickly to the nearby casino and released dense clouds of toxic smoke that traveled upward into the hotel, killing 61 people on floors 16 to 26. The building was closed for nine months for reconstruction and repair and was retrofitted to the 1981 Las Vegas Retrofit Ordinance, which required major revisions to the previous building and fire codes. See “No gambling on fire ordinances” on page 36. The smoky 2008 fire began in an overheated air conditioner unit on the 20th floor. The fire was confined to the air conditioner, and the smoke produced was confined to an employee break area. The fire was reported to the Clark County Fire Dept. at 5:01 p.m. The first responding unit arrived at Bally’s three minutes later. A total of 21 fire department units responded to the fire. The firefighters used the elevator to access the 18th floor and evacuated floors 18 through 21. Heavy smoke was reported on floor 20. Hotel security located a burnt motor on the ceiling air conditioning unit, power to the unit was disconnected, and the fire department verified the fire was extinguished at 5:17 p.m. A second alarm was cancelled at 5:20 p.m., and the fire department units left the hotel at 5:54 p.m. A marked difference Both buildings were concrete-reinforced high-rise structures of nearly identical height. Both buildings were built at approximately the same time period, the early 1970s. The fires in both buildings started in air conditioning units. Both buildings have withstood a major fire without structural collapse. How could two similar fires in similar buildings have such dissimilar results? Why does one event end in a shocking tragedy while a similar event results only in a business interruption? Is it mere fortune that blesses some building occupants, while condemning others to a horrible death or, at best, a lifetime of loss or pain? Specifications, standards, and building and fire codes determine the response of a building during a fire, and the survivability of its inhabitants. While the buildings were similar, one building received a major renovation that rendered it far less susceptible to fire damage than the original building. The foremost building safety improvement of the 1981 Las Vegas Retrofit Ordinance was the requirement for fire sprinklers in high-rise structures of six stories or more. Installation of a retrofit fire sprinkler system at Bally’s ensured that the area surrounding the air conditioning motor would not support continuing combustion of a large fire. The August 2008 fire never reached the temperature required to activate the sprinkler system in the break room. Limits on flame spread of interior finish materials ensured that the overheated motor at Bally’s did not set fire to ceiling, wall, or floor furnishings. The Joelma Building was not sprinklered, and neither was the 1980 MGM Grand Hotel’s casino area, through which a tremendous flame front roared at an estimated speed of 19 ft/sec. The building structural steel in the immediate vicinity of the air conditioning unit at Bally’s was fireproofed and was, therefore, unaffected by the 2008 fire. An area smoke detector mounted within 10 ft of the air conditioning unit alarmed soon after onset of the fire and activated audible alarms and visual strobes on the 19th, 20th, and 21st floors (the floor of incident and the floors above and below the floor of incident). This allowed hotel guests in the rooms closest to the break room to quickly evacuate the area of greatest danger. This area detector also activated the alarm at the Fire Command Center and recalled the service elevator for use by the fire department. Early detection of the fire allowed an alarm to be immediately transmitted to the Clark County Fire Dept. A local power disconnect, required by Section 440 (VII) of the National Electrical Code, allowed a responding maintenance staff member to remove the electrical power flowing to the air conditioner motor and prevent further overheating of the motor. A circuit breaker provided overcurrent protection, although it did not open due to use of the local power disconnect. Construction of the employee break room as a passive smoke zone, with fire-resistant walls, ceiling, floor, and door—and smoke seals on doors and smoke zone boundary penetrations—confined the smoke to the break area. The smoke control system in the hotel corridor outside the break area was never activated by a corridor area smoke detector. Elevator shafts were built smoketight, which allowed the firefighters to use the elevators to quickly access the location of the fire. Automatic doors closed as required to confine smoke to the area of fire origin, and stair pressurization fans blew fresh air into the exit stairwells in the high-rise hotel to prevent any smoke intrusion into these safe exit pathways. The fire code in effect at the time of the Joelma Building fire in 1974 did not place these requirements on the building owner. The building and fire codes in effect at the time of the MGM Grand fire in 1980 also did not place these requirements on the building owner. The result for each building was a catastrophic fire less than seven years after opening. The single unprotected stairway in the Joelma Building further compromised emergency egress and resulted in many more deaths. Requirements that protect building occupants from injury or death and also protect the building from significant damage can be found on the design drawings; on the specifications; in applicable building, fire, mechanical, welding, plumbing, and electrical codes; as well as in the building life safety system’s O&M and emergency manuals and procedures. In undeveloped countries that do not have or do not enforce these restrictive requirements, a significant loss of life may result from a highrise fire. Any one of these requirements can mean the difference between life and death during an emergency situation. Fire tragedies are preventable only if all responsible parties comply with the applicable building safety requirements. Arnold is associate engineer with Clark County (Nevada) Dept. of Development Services. He has extensive megaproject experience and has inspected smoke control systems on the Las Vegas Strip for 13 years. 38 Consulting-Specifying Engineer • MARCH 2009
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