The NRC test table for dynamic wind uplift evaluation of roofing assemblies. The test is performed on a roof system, installed on the lab table just as if it was installed on an actual roof. A retractible dome, connected to a vacuum pump, is then placed on the roofing system equipped with pressure gauges. Air is pumped out of the dome to create a vacuum atop the system as per the CSA protocol. If the system has sustained the required number of cycles to levels of pressure prescribed by the standard, it is given a rating.
Wind resistance tool updated for the National Building Code 2015 location, size, and exposure. Several The Canadian roofing industry is factors, including the type of roof, responding with excitement to slope, wind speed, building height, results of recent wind uplift testing completed by the National Research roof area, building terrain, building type and openings are considered. Council of Canada (NRC). When the design pressure is known, Until 2004, the CSA Standard it is simple to find a suitable roof known as CSA A123.21-04, which covering assembly tested using CSA covers dynamic wind uplift A123.21-14. resistance of membrane roofing “The Wind Roof Calculator is a systems, only addressed duplication of the building mechanically attached code, so whatever is systems. “...a major step specified in the building From 2004 to 2014, towards safer code you can do it in testing for the Standard design of roof Wind-RCI,” said Dr. Bas was expanded to include more types of adhesions, systems across Baskaran, group leader Canada.” for the NRC Institute for as well as fully adhered Research in Construction. systems and hybrid Users of Wind-RCI are taken combinations, explains RCABC through several screens and Technical Manager Rob Harris. encounter pull-down menus where NRC responded to the additions they select factors. by updating its Wind-RCI, an online The calculator was originally wind-resistance tool developed in developed through funding by the 2008. It calculates wind loads RCI Foundation and RCABC. In the affecting building roofs, based on most recent evolution of Wind-RCI, the National Building Code of Canada. Wind-RCI is available for the project raised the limit on architects and designers to calculate building height from 100 to 150 feet for calculations of wind the design pressure based on pressures, allowing more (and taller) several criteria, such as building 10
buildings to be evaluated with the tool. The Wind-RCI calculator is based on a six-step procedure developed by the Special Interest Group on Dynamic Evaluation of Roofing Systems (SIGDERS) and researchers from NRC-IRC. The SIGDERS members are Atlas Roofing Corporation, Carlisle SynTec Systems, CGT, Chemlink Inc., Canadian Roofing Contractors’ Association, Dow Roofing Systems, Duro-Last, exp, Firestone Building Products Co., GAF Materials Corporation, IKO Industries Ltd., Johns Manville, National Roofing Contractors Association, OMG Roofing Products, RCI Inc., ROXUL Inc., Soprema Inc., Sika Sarnafil, Tremco Inc. and Trufast. “Soprema is very proud of the work that has been undertaken by the SIGDERS group over the last 20 years, in which we actively participated,” says Jean-François Côté, Director of Strategic Development for Soprema. “The amount of testing SPRING 2015
Wind-RCI is maintained by the National Research Council of Canada. Its users are taken through several screens and encounter pull-down menus where they select factors. It is available at www.nrc-cnrc.gc.ca/eng/projects/irc/calculator.html.
performed and research done in the NRC laboratory is tremendous. Soprema, like many other manufacturers, donated roof materials (membranes, insulation boards, adhesives, fasteners, etc.) that were used to develop the CSA dynamic wind uplift procedure. Materials were assembled to replicate actual roofing assemblies
and this research allowed the determination of adequate parameters for testing for wind uplift resistance with a dynamic protocol.” “The publication of CSA A123.2114 and its possible inclusion in the 2015 edition of the NBC is a major step towards safer design of roof systems across Canada.” ■ ROOFING BC