Consulting-Specifying Engineer - June 2008 - (Page 30)

rates, or airflow quantities are measured, if required. The testing agency then writes a Non-Conformance Report for any condition that is not acceptable. After the system has been tested successfully to the test plan, a final inspection report is submitted to the Building Division for review and approval. Approval of the final report is the second of two building inspections accepted specifically for the smoke control system (smoke control diagram approval is the first). After the final report is reviewed and approved, the contractor schedules a final mechanical and building inspection. During this inspection, Building Division inspectors ride atop an elevator cage to check elevator shafts for any unsealed joints or utility penetrations. They also perform room walks inspecting each of the thousands of hotel rooms in a single new hotel. Following approval of these inspections, the contractor schedules the fire department and building division for a life-safety systems test, which is an integrated acceptance test Figure 4: All openings in smoke zone boundaries must be considered in the smoke control system, such as this trash chute damper. of all the life-safety systems. A life-safety systems meeting, called a pre-TCO (Temporary Certificate of Occupation) meeting, often is scheduled prior to the system test, with the general contractor, appropriate subcontractors, fire department, building division, and testing agencies in attendance. The system test is performed to the scenarios in the test plan and some of the tests will be conducted with systems on emergency generator power. Occupancy and partial occupancy Upon successful completion of the lifesafety systems test, the general contractor will apply for a Certificate of Occupation for the building. If the building is not complete, a TCO may be granted. All life-safety systems must be complete in the building section to be occupied. If an owner wants to occupy a middle portion of a building while construction continues on lower and upper floors, two buffer floors are required below the occupied floors and one buffer floor above the occupied floors. These measures protect occupants from adjoining construction activities. More floors are required below because hot smoke is naturally buoyant. All life-safety systems must be complete on the buffer floors. However, they will not be occupied because their purpose is to provide some vertical separation between occupied areas and areas still under construction. As an example, floors 8 to 26 of a 30-story hotel would have to be completed to allow floors 10-25 to be occupied. Arnold has extensive megaproject experience and has inspected smoke control systems on the Las Vegas Strip for 12 years. Unique smoke control in Vegas The booming Las Vegas resort construction scene has unique aspects that affect smoke control systems. Many resorts have very large indoor arenas for concerts and sporting events. These arenas generally use either the exhaust method (verify a design exhaust quantity is achieved) or modified airflow method (measure airflow at perimeter openings) for smoke control. The system typically is activated by sprinkler water-flow switches. An integral fixture of the Las Vegas resort scene also is the showroom that houses spectacular stage sets and plush multi-level seating areas similar to opera houses. The extravagant finish materials in the seating areas are protected by layers of fire detection systems, including smoke detectors, infra-red detectors, spark/ember detectors, optical detectors, air-sampling systems, and beam detectors. Additional protection for the seating and show areas is provided by deluge systems and water cannons. Smoke control systems for seating and show areas may operate in different modes using either the exhaust method or the pressurization method, depending on the position of the proscenium curtain. To prevent inadvertent operation of the deluge system, three detection systems often are installed, two of which must alarm before the deluge system is activated. Many Las Vegas hotel properties have extensive convention areas, exhibit halls, and ballrooms. High-ceiling convention areas and exhibit halls typically use the exhaust method for smoke control while ballrooms use the pressurization method, all usually activated by sprinkler water-flow switches. Also, many new resorts are complemented by extensive retail malls on the property. Individual stores are clustered into tenant smoke zones, with 10 to 20 stores in one tenant zone, and the mall area is divided into different mall smoke zones. A mall may be as long as a mile and occupy several levels. Because mall areas typically have expansive ceilings, an individual mall zone can be a very large space. The passive, pressurization, exhaust, and modified airflow methods have all been used in shopping malls. 30 Consulting-Specifying Engineer • JUNE 2008

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Consulting-Specifying Engineer - June 2008 Contents Viewpoint Letters News M/E Roundtable No Gambling Allowed on Smoke Control in Las Vegas Be Prepared: Hospital Protections for Catastrophic Events Ready for Retail Commissioning Documents: Necessary Evil Codes & Standards Codes & Standards Case Study Equipment Lifecycles New Products Advertiser Index Green Space

Consulting-Specifying Engineer - June 2008

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