Welcome to 2017, as we continue to explore UL’s 120+ years of work towards fire safety. This article will discuss a fire safety challenge that is quite recent. Approximately one year ago, during the celebration of the New Year 2016, the world watched as fire rapidly progressed on the exterior of The Address Downtown Dubai hotel. This hotel is located in the area of the Burj Khalifa, the world’s tallest skyscraper, where thousands came to enjoy the New Year’s fireworks display. Those in attendance and countless others around the world watching on TV were shocked to see the hotel building engulfed in flames.
This fire event, along with several others before it, raised great concern over the issue of rapid fire progression on exterior wall construction materials. Other factors that led to a renewed focus on updating the safety testing and certifications available for these materials are the recent significant International Building Code changes pertaining to exterior walls (2012, 2015) which clarify the required testing of these walls. Another influence requiring fire testing of exterior walls is the growing focus on energy efficient (green) construction that requires the increased use of insulation materials within exterior walls, which in many cases requires reevaluation of the exterior wall assemblies.
UL responded to this challenge with a testing and certification program which evaluates exterior wall systems in accordance with NFPA 285, “Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Non-Load-Bearing Wall Assemblies Containing Combustible Components.”
NFPA 285 is the recognized test method for determining the fire propagation of exterior, non-load-bearing wall systems that contain combustible materials. The test method is intended to simulate the fire performance of an entire multi-story exterior wall assembly to assess that the wall does not spread flames over the surface, through the core of the wall and from the compartment of fire origin to adjacent compartments. The procedure uses a two-story test apparatus, commonly known as the Intermediate-Scale, Multistory Test Apparatus (ISMA). The test employs two gas-fired burners, one inside the first story room, and one outside the first story window opening of the wall assembly. Burners are ignited to deliver specified temperatures and heat fluxes over a 30 minute test duration. The conditions of acceptance are based on vertical and horizontal flame propagation limits and maximum temperature limits as measured by thermocouples placed throughout the wall assembly.
Historically, the acceptance of wall systems involve a fairly complex review of building code interpretation, Evaluation Reports (if available), individual component manufacturer’s test reports, engineering analysis, and application of the manufacturer’s installation instructions. The new UL certification categories simplify the review process by providing a public database that shows complete wall system designs, and detailing how individual components are evaluated as part of the systems). This approach meets the dire needs of manufacturers, architects, specifiers, and code officials for an available, accessible, up-to-date method of determining compliance with code. The illustrated designs within the UL certification reflect the precise details of the assembly subjected to the fire test. A UL certified wall system must be constructed to the specifications within the illustrated design and the details included in the associated text to achieve the anticipated performance. Critical components used in the system are named specifically and will also bear the UL Mark. All certified wall systems and components are now published in UL’s Online Directory and in the Building Materials Directory under the categories Exterior Wall Systems (FWFO) and Exterior Wall System Components (FWFX). Examples of wall system components covered by this program include, but are not limited to, foamed plastic insulation, other insulation products, water resistive barriers, air resistive barriers, laminates, sheathing, and composite panels.
Public concern for the fire safety of building facade materials continued throughout 2016 as more fires occurred. While building codes in some countries are prescriptive and detail exactly what material can be included in building facades, building codes in other countries lack this detail. UL has engaged with the premier education center in India, IIT Gandhinagar, to create a test cell and test façade materials for flammability and resiliency. This research work and its findings will be available in 2017 and will hopefully provide the data required for improving building codes and standards for fire behavior of facades.
To learn more about UL’s services for Building Materials & Suppression, please visit UL.com/buildingmaterials. UL’s ISMA apparatus and testing capabilities are located at the fire testing facility in Northbrook, Illinois.
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