Construction Design News

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1 Construction Design News A N AT I O N A L G Y P S U M P U B L I C AT I O N CONTENTS VOLUME 12 ISSUE 1 WINTER 2012 A message from your Construction Design Managers... n I mpact-resistant Gypsum Shaftwall Systems: A Revolutionary System Continues To Evolve By Tom Boissy Tom Boissy tells us how impact-resistant gypsum shaftwall systems continue to evolve. The shaftwall completely changed the nature of the structural system for the two towers, making them the first of a new kind of high-rise building. n How SoundBreak XP Helps With Flanking Transmission Paths By Scott Hughes n Does Recycled Content Mean It s Green? By Mundise Mortimer Scott Hughes explains how SoundBreak XP helps with Flanking Transmission paths. n Bulletin Board Sound, like water, will find the path of least resistance and get through any penetration that is not properly sealed. Mundise Mortimer helps answer the question, "Does Recycled Content Mean It's Green?" Do these potential outcomes offset the benefit of recycled content? Please stay in touch! nationalgypsum.com Let us know if your address changes. any updates or additions to mmortimer@nationalgypsum.com so you can continue to receive Construction Design News.

2 Impact-Resistant Gypsum Shaftwall Systems: A Revolutionary System Continues To Evolve By Tom Boissy, "The Gypsum Guy" How revolutionary was the gypsum shaft wall? While researching this piece, I came across an article by Leslie E. Roberts, lead structural engineer for Skilling, Helle, Christiansen and Roberts, the structural engineering firm for Minoru Yamasaki on the World Trade Center Project. In his article, "Reflections on the World Trade Center," Roberts cited 11 notable innovations that had an impact on the final design. One of these innovations was the gypsum shaftwall partition system. According to Roberts "the shaft-wall completely changed the nature of the structural system for the two towers, making them the first of a new kind of high-rise building." The gypsum shaftwall was developed in the 1960s. Construction of the twin towers started in 1968 and finished in During the design of the World Trade Center, the structural engineering firm for the project established a new design criterion to overcome existing shortfalls in the relatively new shaftwall system to meet the needs of the 100-story-plus building. The benefits of gypsum shaftwall were many, but foremost were the reduction in weight, increased flexibility, and the speed and ease of installation which eliminated scaffolding. These benefits reduced construction costs and are still relevant today. Like any mature technology, gypsum shaftwall continues to evolve, and lessons learned from the World Trade Center are once again the stimulus. On August 26, 2006, the City of New York amended Section 1 of the building code. The new section amended title 1 of the Rules of the City of New York, Section Impact Resistant Stair and Elevator Enclosures. This new section was a direct result of the lessons learned after the World Trade Center disaster. The New York City Department of Buildings developed the requirement, and in 2009 the International Building Code (IBC) adopted a similar requirement, Section Structural Integrity of exit enclosures and elevator hoist way enclosures. For more detailed design and code information, please refer to the appropriate sections of the IBC Code or the building Tom Boissy, CSI, CCPR, LEED AP "The Gypsum Guy" Construction Design Manager Mobile tpboissy@nationalgypsum.com code that governs your project. The code requirement pertains to specific building types and sets forth minimum design criteria for shaftwall impact-resistance. This is based on performance testing per ASTM C 1629 and C 1629 M -Classification for Abuse Resistant Non- Decorated Interior Gypsum Panel Products and Fiber Reinforced Cement Panels. In 2006, the gypsum industry adopted ASTM C 1629 as the testing standard for measuring the performance of all abuse and impact panels. A copy of ASTM C 1629 can be ordered from astm.org. National Gypsum has two products that are tested per ASTM C 1629 and can meet the impact-resistant shaftwall requirements: Gold Bond brand Hi-Abuse XP Gypsum Board and Gold Bond brand Hi-Impact XP Gypsum Board. Both boards are 5/8-inch thick and Type X for use in UL fire-rated shaftwall designs. The diagram shown here is one assembly that meets these code requirements. Please call your Construction Design Manager or one of our technical managers at NATIONAL for answers to your shaftwall design questions. You can also reach the technical managers at techservice@nationalgypsum.com. Source: Roberts, Leslie E., "Reflections on the World Trade Center," The Bridge, Vol. 32, No.1 Spring 2002:5-10. Print. n

3 How SoundBreak XP Helps With Flanking Transmission Paths By Scott Hughes In our last issue of Construction Design News, Mundise Mortimer interviewed National Gypsum s Director of NGC Testing Services, Bob Menchetti. In "Deciphering the Decibels of STC Ratings," Bob walked us through the details behind STC ratings. The discussion focused on why Gold Bond brand SoundBreak XP is the right product to reduce sound transmission through your wall assembly. Bob also explained how two different wall assemblies with the same STC rating could perform quite differently. To refresh your memory, refer to the Summer 2011 issue of Construction Design News. In this issue, I thought we would expand our horizons and talk about another factor to think about when specifying any higher rated STC wall assembly. One of the big issues to consider on any project is a Flanking Transmission path. Flanking Transmission paths (Figure A) are areas in a wall assembly that allow sound to travel easily through it. In this illustration, sound from hard-soled shoes on wood flooring can travel underneath the wall assembly to the other side. Acoustical caulking is needed to help reduce this transmission. Use an acoustical sealant that is applied per ASTM C 919. Other areas to think about are electrical boxes for outlets, data lines and switch plates. If not properly sealed, these can allow sound to leak right through them. Offsetting electrical boxes by one stud space (as shown in Figure B) will help reduce these Flanking Transmission paths as well. Specify a putty pad that has been tested per ASTM E 90 to wrap the back side of the electrical boxes after the wires have been run through them. Sound, like water, will find the path of least resistance and get through any penetration that is not properly sealed. Looking for the right SoundBreak XP wall assembly? Check out the Acoustical Selector Guide at nationalgypsum.com. Here you ll find many of our third-party, full scale STC tested assemblies on both wood and metal studs. After the description of each assembly, you will see the third-party independent test number. Click on that number to download the actual test data in PDF format. This test data shows you how well the wall assembly performs in the entire range of frequencies that are tested for a STC rating. If you can t find what you re looking for, call our technical managers at NATIONAL. SoundBreak XP is a very important part of any high STC wall assembly. After all, it is abuse resistant (ASTM C 1629), mold and mildew resistant (ASTM D 3273) and GREENGUARD Children & Schools SM Indoor Air Quality Certified. Quite a few architects that have specified Scott Hughes Construction Design Manager Mobile swhughes@nationalgypsum.com SoundBreak XP on their projects have told me how pleased their clients are with its performance. One architect in Virginia told me that her client went out of his way to tell her how quiet their new walls are. We continue to test new wall and floor/ceiling assemblies and will publish that data when the test results are in. Remember, if you can t find what you re looking for, put us to work for you. If we don t have an answer, we will get it for you. n Figure A Figure B

4 Does Recycled Content Mean It s Green? By Mundise Mortimer, LEED AP The U.S. Green Building Council (USGBC) LEED Projects Directory lists over 11,000 certified projects and over 32,000 registered projects. LEED has driven demand for green building products including high recycled content. Yet, we all know that it takes more than recycled content to be a green product. High recycled content gypsum board uses byproduct gypsum derived from cleaning the emissions of coal-fired power plants. It is also known as synthetic gypsum or FGD, short for Flue Gas Desulphurization. LEED projects typically emphasize using high recycled content materials. Some specs even require high recycled content gypsum. This would seem like the right thing to do, but there are points to consider before adding this to your specs. Where is the recycled content located? Depending on the project location, gypsum board may or may not be able to contribute to this credit. The map below shows all of the high recycled content plants in the United States. There is virtually no production of recycled content west of the Mississippi River. Can a project get LEED certified without high recycled content gypsum? The LEED certification process is essentially a scorecard. Unlike a football game that awards points every time the ball goes into the end zone, LEED limits the points in each of the categories. This is the equivalent of limiting a football score to one field goal per game. LEED allows a maximum of three points for recycled content. Gypsum can contribute anywhere from less than 1 percent to more than 10 percent of this credit, depending on the type of project. It is unlikely that gypsum would be the only material factored into this credit. Higher recycled content may be pursued for reasons other than LEED. Let s review potential tradeoffs associated with this requirement. Competitive bidding may be limited due to availability. Higher freight costs may result from shipping greater distances. Local jobs may be affected by shipping from outside the area. Some specialty products may not be available with high recycled content because most plants do not produce the manufacturer s full product line. Do these potential outcomes offset the benefit of recycled content? That s a decision best made by the project team, but it should be part of the decision to require high recycled content gypsum. Mundise Mortimer, LEED AP Manager, Technical Marketing Office mmortimer@nationalgypsum.com What about regions that have no recycled gypsum nearby? California has over 1,200 LEED certified projects and there is no recycled gypsum available within 1,000 miles of the state. I mention this to point out that LEED certification is attainable without high recycled content gypsum. Gypsum board is a readily available, cost-effective solution for walls and ceilings and provides inherent fire resistance. National Gypsum products are GREENGUARD Children & Schools SM Certified for Indoor Air Quality. Other properties that contribute to a highperformance building include resistance to mold, abuse and impact resistance and enhanced acoustical performance. Our e 2 XP line of fiberglass-faced gypsum products offers an extended exposure warranty in addition to mold resistance. And of course, we have used 100 percent recycled paper for the past 50 years. Due to the plant network, the gypsum core can often contribute to Regional Materials because it is extracted and manufactured within 500 miles of the project. National Gypsum is a big proponent of recycled content. Our plants in Apollo Beach, Fla.; Mt. Holly, N.C.; Shippingport, Pa.; and Westwego, La., use byproduct gypsum. Some other plants use significant blends of natural and byproduct gypsum, Continued on next page

5 which can be as high as a 40 percent synthetic blend. We have a program in the Northeast to recycle gypsum scraps from new construction back into the manufacturing process. We also believe products made at our natural rock plants offer excellent performance benefits for LEED projects in those local markets. Consider the "big picture" in order to attain LEED credits. Locally available, high recycled content is an inexpensive way to contribute to the Recycled Materials credit. If material is not readily available, there may be hidden costs incurred or other unintended consequences. We encourage you to look at the bigger picture when specifying recycled content for gypsum. If you have questions about the availability of recycled content for your project, gps.nationalgypsum.com provides a project specific report. We share this with you to help you make the best decisions for your project and hope you will continue to think of National Gypsum as a sustainable resource for all of your projects. n B U L L E T I N B O A R D New Online Continuing Education Courses At McGraw Hill Click on McGraw Hill Construction Continuing Education Network to check out three new Continuing Education Programs: Finishing Gypsum Board: Appearance and Indoor Air Quality Review the relevant standards, common materials and terminology used for gypsum board finishing followed by a detailed discussion on indoor environmental quality standards and procedures. Acoustically Enhanced Gypsum Board Designed for High STC Wall Assemblies Learn about different sound resilient assemblies available for the design and construction of high STC wall partitions. You ll gain a better understanding of conventional construction methods as well as an innovative means of decreasing sound transmission. High Performance Gypsum: Protect against mold, moisture and exposure The focus is on gypsum products manufactured with fiberglass facing, which replaces the paper facing typically used on gypsum board. These products are regarded as "high performance" due to their weather resistance, fire resistance, mold resistance and strength. By understanding these products, you can properly prepare specifications and drawing details for successful use in buildings. High Strength Fire-Shield LITE Gypsum Board New Gold Bond brand High Strength Fire-Shield LITE Gypsum Board is formulated to be up to 15 percent lighter than standard 5/8" Type X gypsum board. The specially formulated lightweight properties of High Strength Fire-Shield LITE offer a choice for projects that specify Type X gypsum board. Benefits include: Lighter weight results in easier handling The lighter weight, combined with GridMarX guide marks, improves jobsite productivity and reduces waste through easier handling, more accurate cuts, less measuring and uniform fastener patterns. Improved productivity Reduced transportation costs Fire resistant Type X designation UL Classified and approved for specific UL fire-rated designs GREENGUARD Children & Schools SM Certified for Indoor Air Quality For more information, go to highstrengthlite.info or call NATIONAL for technical information. For a complete list of UL fire-rated designs, visit ul.com. National Gypsum BIM Content We want to help make your job easier. National Gypsum has developed BIM objects for building, design and construction professionals to use in design, specification and scheduling. The objects are available through Autodesk Seek. These system families provide Revit users with models that integrate manufacture specific data into drawings and specifications to streamline workflow and improve accuracy. BIM models are the latest offering from National Gypsum to support the building and design professional. The addition of this content enhances existing web-based tools such as the Submittal Builder and Green Product Score (GPS). The team at NATIONAL continues to provide the best technical support in the industry.