For example, if the 2006 or 2009 IBC is in effect, then ASCE 7-05 governs. Although the wind speeds along the U.S. Atlantic and Gulf of Mexico hurricane coastline are similar, ASCE 7-16's wind speeds in the central U.S. are slightly lower and in the West are notably lower than ASCE 7-10's wind speeds. Use approval listings to select the appropriate roof system. . Design uplift pressures are adjusted by multiplying the velocity pressure (qh) by the appropriate external pressure coefficients (e.g., GCp), as shown in Figure 6. And with the latest version of ASCE 7, "Minimum Design Loads For Buildings and Other Structures" (ASCE 7), it has become that much more challenging for roof system designers and roofing contractors. Taking time for simple winter roof maintenance can help prevent leaks and roof damage before they occur. If the 2012 or 2015 IBC is in effect, then ASCE 7-10 governs. Don was able to provide much insight as to what went into the changes to the wind speed maps and roof pressure coefficients. As covered previously, ASCE 7-05 and ASCE 7-10 have three classification types: Open, Partially Enclosed, and Enclosed, while ASCE 7-16 added Partially Open and slightly modified the definitions. It is not intended to constitute financial, accounting, tax or legal advice. Select a roof system with a tested capacity that meets or exceeds the design wind loads. While most of the country will appreciate some wind pressure reductions, there will be more regional variability nationwide than in previous editions of ASCE7 due to the new wind map contours. Before we get into a discussion about the wind design process, it's appropriate to discuss the requirements in the building code. Along the way I've learned a few things. ASCE 7-16 added another zone and it presents the potential to have four roof zones: interior, field, perimeter and corner, see Figure 3. ASCE 7 uses the following base equation to determine velocity pressure (qh):qh = 0.00256 (Kz)(Kzt) (Kd) (V2)(I), Where:qh = velocity pressure at mean roof heightKz = exposure coefficient based on exposure and heightKzt = topography factor (likely 1.0)Kd = wind directionality factor (Components and Cladding uses 0.85)V = basic wind speed for the locationI = Importance Factor (based on Occupancy Category). Are you familiar with the changes to the wind provisions in ASCE 7-16?  He also presented the changes to the roof pressure coefficients, and explained the effects of the new Elevation Factor. Providing this information on the construction documents ensures the contractor and manufacturer (together or separately) can provide an appropriate roof system with tested capacity. On the other end of the line, Rachel Engelstein, VP and Chief Litigation and Compliance Counsel, had the same thought, that this was something long overdue for real conversation. Using "Partially Enclosed" as the building type results in an increase of about one third in the design wind pressures in the field of the roof versus an "Enclosed" or "Partially Open" building—all other factors held equal. Also, ASCE 7-16's maps include midpoint indicators between the maps' wind speed contours. The ASCE 7 peak-gust map differs from the ASCE 7-93 wind map ~ASCE 1993! Wind Examples ASCE 7-10/ ASCE 7-16 Illustration of Calculations Meca Enterprises, Inc. 836 West Jasper St. The Velocity Pressure is the 'foundational' load that is used to determine the design wind pressures for each zone of a rooftop. The main changes in wind loads from ASCE 7-05 to ASCE 7-10 are: • Base wind loads are Ultimate rather than ASD • Occupancy/Importance factor built into Wind Speed Maps rather than included in equations • Introduced inclusion of Exposure D in Hurricane Prone Regions • Revised triggers for Hurricane Prone Regions and Wind Borne Debris Regions And lastly, SPRI sponsors the Directory of Roofing Assemblies (DORA) which is an online database of tested assemblies. © Copyright 2018 SE Solutions, LLC (providers of SE University) | Website by, SE University, Provided by SE Solutions, LLC, Continuing Education Requirements by State, Applied Technology Council’s (ATC) WINDSPEED BY LOCATION, “SEU Speaker Inspires” Organization of the Month: Harvest Hope, “SEU Speaker Inspires” Organization of the Month: World Wildlife Fund, “SEU Speaker Inspires” Organization of the Month: Doctors without Borders, “SEU Speaker Inspires” Organization of the Month: Structural Engineers 2050 Commitment Program SE2050. Date change due to speaker availability – Session will also be rebroadcast on January 13th Speaker: Kim Olson, PE Steel Tube Institute AISC 360, Chapter K underwent a significant change in the 2016 Specification. GAF is happy to share our website content with you through our free media sharing service. GAF does not guarantee the accuracy, reliability, and completeness of the information. In general, the greater the importance of a building, the higher the Importance Factor or Risk Category which results in higher uplift pressures. It's important to recognize there are two basic steps used to determine design wind pressures acting on a roof. The equation to determine velocity pressure varies slightly in ASCE 7-05, ASCE 7-10 and ASCE 7-16. Here's a look back at some of the ways GAF has made a positive impact on more than 6,000 families this year. This process results in Design Wind Pressures for each roof zone and determines the dimensions for each of the zones (although not discussed in here). An abrupt change in the topography, such as escarpments, hills or valleys can significantly affect wind speed. New Risk Category IV Wind Speed Map – 7th Edition (2020) FBCB (ASCE 7-16 Figure 26.5-1D) While the wind speed maps in ASCE 7-16 have been revised significantly for the nonhurricane-prone region, for the State of Florida, the only significant change to the wind speed maps is the introduction of a new wind speed map for Risk Category IV buildings Simply put, a roof assembly must be able to resist the design wind loads acting on the rooftop. (October 2017), respectively. "For the first time, I formally spoke out loud of the things that were happening—the real hurdles we face as women in sales within the predominantly male roofing industry." Don offered two permitted web based tools that may be used to access wind speed data for various locations in the United States. The web based format is very cost-effective and beneficial as it allows our staff to attend each session in our own conference room and have a concurrent open discussion about how best to utilize the information presented.”, ~Donald G. Corson, P.E. ... 22 SEISMIC GROUND MOTION, LONG-PERIOD TRANSITION, AND RISK COEFFICIENT MAPS . Figure 5: Interior Pressure Coefficients, GCpi, for ASCE 7-16. to ASCE 7-16 The wind pressure on building surfaces .  This tool provides all design parameters specified by ASCE 7-16 for a given site. ASCE 7‐16 –Wind Provisions MRI Design Wind Speed Maps Risk Category Target Beta (Ch.1) Current Map MRI Proposed Map MRI I 2.50 300 300 II 3.00 700 700 III 3.25 1,700 1,700 IV 3.50 1,700 3,000 ASCE 7‐16 –Wind Provisions • Incorporate analysis of additional wind climate data for … These tests are run by approved testing agencies. Your roof works hard to protect your home from snow, rain, and storms. If it were only that simple! FM Approvals, Underwriters Laboratory, Intertek, NEMO, PRI, and others can perform testing—according to the code-approved test methods—that can be used to determine a roof system's capacity. . It's a hardy structural engineering discussion! This ventilation system consists of both ridge vents installed at the peak of the roof and intake vents installed at or near the soffits. ASCE 7-16: Changes to Wind Calculations for Rooftop Solar Joe Cain, P.E. El Paso, TX, “Feedback I’ve been getting from others (in my office) is that these seminars are excellent, not at all like the standard seminars that we have seen from others. Yet while it certainly can be complicated, there are ways to break down the steps of wind design in order to make it much more digestible for architects and specifiers. Linear Interpolation of Wind Speed Maps (ASCE 7 16) Structural Ultimate Wind Load Design Gust Wind Speeds in the United States Design” wind speed map defined as V 700 / ͱ 1.6 | Download Ultimate Wind Load Design Gust Wind Speeds in the United States Email This BlogThis! The series will cover the basics of wind engineering including the atmospheric and aerodynamic effects of wind on buildings. Determining the height, length, and width of a building should be straightforward and a vast majority of buildings are predominately square or rectangular in shape, or in general, have square or rectangular roof areas. The 2018 IBC (as well as prior versions) has very specific requirements for what is to be included on the construction documents regarding wind design of roof systems. For additional information regarding the changes to the 2005, 2010 and 2016 editions of ASCE 7, refer to the following articles by Thomas L. Smith published in Professional Roofing Magazine: "ASCE 7 update" (June 2008); "Mapping the 2010 wind changes" (August 2010); and "How do I load thee?" The changes (from ASCE 7-10 to ASCE 7-16) that impact wind pressures on low-slope roofs are described in the follow-ing sections. The wind speed increase is known as a wind speed-up effect. The tested roof systems are found in approval listings. Download Image. There are a number of factors that determine the design wind uplift loads for the field, perimeter, and corners of a roof. To help in this process, changes to the wind load provisions of ASCE 7-16 that will affect much of the profession focusing on building design are highlighted. See Figure 5. What Wind Speed Should I Use For My Project? Note: This blog is not going to try to explain the difference between ASD and Strength Design loads. is due to the kinetic energy contained in moving air, which is a function of wind speed and the density of air.  The first option is the Applied Technology Council’s (ATC) WINDSPEED BY LOCATION website which available free of charge. 2020 was a tumultuous year, full of unknowns and adjustments—some natural and others forced by the pandemic. During the same time period when the wind load map was being developed, the ASCE 7 committee examining load factors increased the load factor from a value of 1.53 to 1.6. The key difference being that FM did not adopt the wind maps utilized by ASCE 7-16 and the 2018 International Building Code. The first step is to determine velocity pressure; the second step is to use velocity pressure to determine design wind loads for roof zones (e.g., field, perimeters, and corners). Ensure that an appropriate safety factor is included on either the load side or the resistance side. Asce 7 Wind Map ASCE 7-16 Wind Load Provisions Tools Of The Trade: Wheatland Wind Load Fence Post Size ASCE 7 10 To 7 16 Changes For Glass & Glazing Design. What Are the Parts of a Residential Roof? For more information about Resilient Roof Systems, read this blog. Figure 6: External Pressure Coefficients, GCp, for ASCE 7-16. Thus when ASCE … McComas Engineering Therefore, step one is to determine the loads acting on the roof of a specific building. 2020 has been a year of monumental change, pushing many companies to consider how they can be better, how they can do things differently, and—most importantly—how they can help.Corporate social responsibility (CSR) efforts allow GAF to bring about meaningful change in the communities it serves and within its own company. Roof systems that have the tested capacity to resist calculated wind loads can be found in approval listings (e.g., UL, FM). Please complete the information below. Minimum Design Wind Loads for the respective direction according to ASCE/SEI 7‑16 27.1.5; Case 1: Full design wind pressure acting on the projected area perpendicular to each principal axis of the structure, considered separately along each principal axis. HKN Engineers However, the factors selected by a conservative owner (e.g., choosing Partially Enclosed) also have an effect on the design wind loads.  Also, new hurricane models have reduced the hurricane winds along the northeast coast, while the hurricane winds along the southeast coastlines remain unchanged. So, what are the most important lessons learned in 2020 that we can apply to the year ahead? Select roof systems that have been tested in accordance with code-approved test methods by accredited testing laboratories. Together it was decided—we need to do something more. Be on the lookout for updates from GAF Roof Views in your inbox. Select roof systems that have capacity greater than the loads acting on the building. In general, the greater the importance of a building, the higher the Importance Factor or … . The primary method for determining a roof system's wind uplift resistance (aka, capacity) is through physical testing. If the 2018 IBC is in effect, then ASCE 7-16 governs. In ASCE 7-05 for example, I—the Importance Factor—is in ASCE 7-05 only. Understanding the similarities and differences between the three versions of ASCE 7 provides for better recognition of the current version's complexity and allows for more appropriate wind load determination. Very well done to date.”, -Robert Ray, P.E. What may be best in terms of lowest up-front costs, may prove only good or worse over the long-term life of the building. Research and experience has shown that wind speeds can increase significantly due to topographic effects. These are shown in Figure 5. Wind Speed Maps - ASCE 7-16 « on: March 09, 2018, 11:12:56 am » I don't know about the rest of you but when I look at the new wind speed maps in the ASCE 7-16, in particular the eastern United States I find the contour lines a bit confusing. Map Key. The values for External Pressure Coefficients have been significantly increased in ASCE 7-16.  The second option is ASCE 7 HAZARD TOOL which is available to registered members. ASCE 7-05 uses Occupancy Category to determine the value to use for the Importance Factor.  Don covered the changes to the new wind speed maps and explained how to determine the design wind speed. Photo detail for ASCE 7-10 Wind Speed Map: Title: ASCE 7-10 Wind Speed Map Date: September 13, 2018 Size: 2548kB Resolution: 4300px x 3062px Download Image. By submitting your application, you agree to our. ASCE 7 uses three Surface Roughness Category types—called B, C and D—which in turn, defines three Exposure Category types, also called B, C and D. Exposure Categories B, C and D are generally defined as follows: The use and occupancy of a building is used to determine the "Occupancy Category" in ASCE 7-05 or "Risk Category" in ASCE 7-10 and ASCE 7-16. MecaWind includes ASCE 7-05, ASCE 7-10 and ASCE 7-16, and includes all of the changes in the new standard. Sections of IBC 2018 that reference the ASCE 7 -16 wi nd maps (which do not match the 2013 Colorado Front Range Gust Map) include 1609.1.1 and 1609.3. ASCE 7-16 Update A. Lynn Miller, P.E. This three-part webinar series discusses how to use the wind load provisions of ASCE 7-16 Minimum Design Loads for Buildings and Other Structures. After determining the velocity pressures, the next step is to calculate the design uplift pressures specific to the interior (if applicable), field, perimeter, and corner zones of a roof. The handout email for this session will be sent to SE University companies on Friday, January 8th. An architect/designer needs to know a building's location; the building code that is in effect at the building's location; its height, length, and width; the exposure category; the use and occupancy category; the enclosure classification; any topographic effects; and ground elevation in order to determine the wind loads acting on a roof. They are effectively interchangeable terms, however, they are addressed differently. In situations where a specific version of ASCE 7 is not mandatory, using the most recent version of ASCE 7 is recommended. This is where much of the concern with ASCE 7-16 lies—the increase in the External Pressure Coefficients—and how the increases will affect design wind pressures. ASCE 7-10 and 7-16 incorporates Risk Category (i.e., importance factor) into the wind speed maps, and that is why there are 3 maps in ASCE 7-10, and 4 maps in ASCE 7-16. The test methods to determine wind resistance are listed in the IBC Section 1504, Performance Requirements. 1. The internal pressure coefficient values are based on the building design (i.e., the enclosure classification). (See Determining Resistance below for more information.). Speaker: Kim Olson, PE Steel Tube Institute AISC 360, Chapter K underwent a significant change in the 2016 Specification. Retrofit Single Ply Roof Systems: Physical Testing, Corporate Social Responsibility at GAF: 2020 Year in Review, Practical Winter Roof Maintenance in 3 Steps, Employee Happiness at Work: Why It Matters. ASCE 7-16 amended these classification types by adding another type called, "Partially Open" and also revised some of the definitions. Wind ASCE 7-10 v ASCE 7-16 • Except in hurricane areas, wind speeds have reduced by about 10% – More weather stations available now – Increased forestation & urbanization – Reliabilities of old maps “not right” • At high altitude locations wind pressures can be … Because of the different configurations of the roof zones and other factors that are intended to allow for a correction (i.e., a reduction) in velocity pressure, it is hard to state—broadly—a percentage that loads may increase. or amend all IBC 2018 references that permit use of the wind speed maps in ASCE 7 -16; otherwise, use of unconservative wind speeds may be permitted.  The new maps now reflect more regional variability in extreme wind climates.  Wind speeds in the great plains remain unchanged, but for the rest of the country wind speeds have decreased, most significantly along the west coast. Laboratories, and storms your home from snow, rain, and storms your.... 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