Evaluation of a PanElizEd Eifs wall assembly system

Transcription

1 Evaluation of a PanElizEd Eifs wall assembly system ChriS norris, Pe, Leed AP, Cei morrison HersHfield 1455 Lincoln Parkway, Atlanta, GA Phone: Fax: cnorris@morrisonhershfield.com dominick P. baruffi ii Jersey panel corporation 907 North Main Rd., Vineland, NJ Phone: Fax: dbaruffi@jerseypanel.com S y m p o S i u m o n B u i l d i n g E n v E l o p E T E c h n o l o g y n o v E m B E r n o r r i S A n d B A r u F F i 1 0 9

2 AbStrACt Panelized exterior wall systems are becoming increasingly popular due to the improved quality control and shortened construction schedules that can be achieved with a panelized approach. This presentation covers a review of some existing panelized EIFS installations along with laboratory performance testing of a panelized EIFS wall assembly. The tested assembly included panel joints, a window, and an electrical penetration. The system was subjected to a series of tests to evaluate water penetration resistance, air leakage rates, and structural capabilities. Two window installation methods were tested: Baseline testing was completed in accordance with window manufacturer details, and an alternate installation was tested with improved window installation details. SPeAKerS chris Norris morrison HersHfield CHRIS NORRIS is a senior building envelope specialist with Morrison Hershfield, based in Atlanta, Georgia. He is a licensed professional engineer with over 15 years of consulting experience on projects throughout North America. His project experience includes design consultation for new construction projects, field review and field performance testing, condition assessments, research assignments, expert-witness assignments, rehabilitation assignments, and structural design of glazing systems. His experience includes both low-rise and high-rise projects. A few current and recently completed projects include the 50-story Devon Energy World Headquarters building in Oklahoma City, OK; the SLVHCS replacement hospital campus in New Orleans, LA; and the 27-story Seneca Tower residential apartments in Seattle, WA. dominick baruffi Jersey panel corporation Raised in a family plastering business started by his father and uncles in 1947, today DOMINICK BARUFFI serves as president/ceo of that original company Baruffi Bros. Inc. as well as president/ceo of its sister company, Jersey Panel Corporation, a prefabricator of exterior wall systems. Educated at the Stillman School of Business (Seton Hall University), Baruffi began his career right out of college by working his way up the ranks of the family business from a laborer in the field to plaster mechanic, into sales/marketing, and, in 1988, taking on the role of CEO. In 2011, the Sto Corporation, along with company CEO David Boivin, tapped Baruffi to serve as executive director of Sto Panel Technology, a division that focuses on the prefabrication of exterior wall systems n o r r i S A n d B A r u F F i S y m p o S i u m o n B u i l d i n g E n v E l o p E T E c h n o l o g y n o v E m B E r

3 Evaluation of a PanElizEd Eifs wall assembly system Panelized exterior wall systems offer the opportunity for improved quality control by moving many of the exterior wall construction operations from the job site to a controlled factory environment. By eliminating the impacts of weather and site conditions, panelized exterior wall systems can also reduce construction schedules. There are many panelized exterior wall systems currently on the market. These include unitized curtain wall, precast cladding, and foam core metal panels. This paper describes the evaluation of a panelized-barrier exterior insulation and finish system (EIFS) that is manufactured and installed by a panel fabrication company affiliate of the EIFS manufacturer (Figure 1). The tested system consists of EIFS cladding over an air barrier, exterior sheathing, and light-gauge steel stud framing. This system is intended for use on steel-framed or concrete-framed structures. The scope of evaluation included water penetration, air leakage, and structural testing of a panelized EIFS test assembly. Panelized EIFS have been used by the panel fabricator on many projects, and several of these were visited as part of this evaluation. The evaluation also included laboratory testing of a panelized test assembly wall to evaluate system performance. Figure 1 Panelized barrier EIFS. ExISTING INSTALLATIONS Morrison Hershfield was provided a tour of several panelized barrier EIFS projects located in Atlantic City, NJ, and Atlanta, GA. These projects were reviewed visually from the exterior from grade. There have been no reported failures with any of these existing projects. These projects demonstrate the wide range of architectural design flexibility that is possible with a panelized EIFS system. The following photographs highlight some of Photo 2 Caesars Palace in Atlantic City, NJ. these panelized EIFS projects. See Photos 1-3. Photo 3 Mayfair Renaissance in Atlanta, GA. Photo 1 Office building in Atlantic City, NJ. S y m p o S i u m o n B u i l d i n g E n v E l o p E T E c h n o l o g y n o v E m B E r n o r r i S A n d B A r u F F i 1 1 1

4 Photo 4 Panel prior to window installation. Figure 2 Window head detail. TEST ASSEMBLY FABRICATION ERECTION The test assembly included two EIFS panels, a vertical sealant joint between the panels, a window installation, and an electrical box installation. The panels were single-span, supported by horizontal steel beams, which were used to simulate building floors. The tested panels used a barrier EIFS. The electrical penetration and panelto-panel joints were sealed with dual-stage silicone sealant joints. The innermost sealant joint was installed over an open-cell backer rod, while the outer joint was installed over a closed-cell backer rod. A dual silicone sealant joint was around the window perimeter, with the outer joint installed from the exterior and the inner joint installed from the interior. Figure 4 Windowsill detail. PANEL FABRICATION The EIFS panels used for this laboratory evaluation were fabricated at the panel fabricator s facility following the manufacturer s standard fabrication protocols. The stud framing, sheathing, air/weather barrier coating, insulation, and finish were all applied at the fabrication facility. Air/ weather barrier coating and air/weather barrier wraps exposed edges of each EIFS panel. A window opening was provided in one panel for installation of the window at the testing laboratory. A block-out was left in the other panel to receive an electrical box. Figures 2-6 show the sealant joint details. These panels were shipped to the testing laboratory for installation on a test frame. Refer to Photos 4-6 and Figures 2-6 for photos and shop drawings of the tested assembly. PANEL ERECTION The EIFS panels were erected by the panel fabricator. The panel-to-panel sealant joint and the electrical box penetration sealant were installed by a sealant contractor. The window and associated sealant joints were installed by a window contractor. This simulates the common division of scope for installation of this system where the Figure 3 Window jamb detail. Figure 5 Panel-to-panel joint detail n o r r i S A n d B A r u F F i S y m p o S i u m o n B u i l d i n g E n v E l o p E T E c h n o l o g y n o v E m B E r

5 Photo 5 Panel joint and electrical box prior to installation of sealants. Figure 6 Electrical box penetration detail. panel fabricator provides and installs the panels, and other subtrades install windows, electrical penetrations, and sealant joints. The window was installed in a sill pan with structural attachment of the sill pan to the EIFS panel stud, framing in accordance with the window manufacturer s details. Manufacturer s window attachment details were used without modification in order to allow for an objective evaluation of the window and the window installation method in conjunction with the panelized EIFS, as might occur on a real project. Refer to Photos 7 and 8 for sill pan installation. The frame assembly provided by the testing laboratory included tube steel framing, which was used to simulate floor slab conditions. The field condition includes a continuous metal plate anchored along the perimeter of the floor slab to receive the EIFS panels. In the tested assembly, the steel tube was used in place of this continuous plate. The EIFS panel was connected to the steel tubes using steel plates and solid rods. Photo 6 View of completed assembly. Photo 8 Sill pan installation showing sealant applied over fastener head and at end dams. Photo 7 Sill pan installation showing fastener through sill pan. S y m p o S i u m o n B u i l d i n g E n v E l o p E T E c h n o l o g y n o v E m B E r n o r r i S A n d B A r u F F i 1 1 3

6 Photo 9 Bearing connection. Photo 10 Nonbearing connection. These connection details were identical to the detailing used on typical projects, with the exception that a steel tube was used in place of a continuous plate anchored to a concrete floor slab. Refer to Photos 9-10 and Figures 9-10 for connection details. Figure 9 Bearing connection. LABORATORY WALL ASSEMBLY TESTING BY ATI The exterior wall mock-up assembly was laboratory-tested at Architectural Testing, Inc. (ATI), in york, PA, 1 to evaluate the water penetration, air leakage, and structural capabilities of the panelized EIFS (Photo 9). TEST METHODOLOGY Although dual-stage joints are provided between panels and at all penetrations, the tested assembly is considered to be a barrier wall system since there is no drainage plane between the EIFS insulation Figure 10 Nonbearing connection. Photo 11 Mock-up testing setup n o r r i S A n d B A r u F F i S y m p o S i u m o n B u i l d i n g E n v E l o p E T E c h n o l o g y n o v E m B E r

7 and the sheathing. In consideration of the requirements of the International Building Code (IBC), Chapter 14 2 for nondrained wall assemblies, the mock-up was subjected to a two-hour water penetration test. The mock-up was tested for water penetration, air leakage, and structural performance. All tests were conducted in accordance with standard test methods (ASTM and AAMA tests). The following test methods were utilized: ASTM E330, Standard Test Method for Structural Performance of Exterior Windows, Doors, Skylights, and Curtain Walls by Uniform Static Air Pressure Difference. ASTM E283, Standard Test Method for Determining Rate of Air Leakage Through Exterior Windows, Curtain Walls, and Doors Under Specified Pressure Differences Across the Specimen. ASTM E331, Standard Test Method for Water Penetration by Uniform Static Air Pressure Difference. AAMA 501.1, Standard Test Method for Exterior Windows, Curtain Walls, and Doors for Water Penetration Using Dynamic Pressure. The mock-up was first subjected to a structural preload of 50 percent of the design pressure (25 psf [1.20 kpa]) followed by air leakage and water penetration testing, which was used to establish baseline performance. The mock-up was then subjected to a full structural design pressure of 50 psf (2.40 kpa) and retested for water penetration and air leakage (see Table 1 for the test protocol). The water testing included a two-hour water penetration test at a test pressure of 6.24 psf (299 Pa) in accordance with IBC requirements for barrier exterior wall systems. The mock-up was also subjected to a series of 15-minute water penetration tests, with static test pressures of 8, 10, and 12 psf (383, 479, and 575 Pa) and a dynamic water penetration test at a 12-psf (575-Pa) test pressure. Following completion of all tests, two 2-in.-long sections of the exterior sealant were removed. One section was removed from the panel-to-panel sealant joint, and one section was removed from the electrical box sealant joint. The water testing was then rerun for 15 minutes at 12 psf to evaluate the impact of real-world con- TEST PROTOCOL a. Structural preset. ASTM 50% (25 psf) b. Air leakage (ASTM 6.24 psf c. Static water resistance (ASTM E331) 2-hour 6.24 psf d. Static water resistance (ASTM E331) 15-minute 8, 10, and 12 psf e. Dynamic water resistance (AAMA 12 psf f. Structural performance (ASTM 100% design pressure (50 psf) g. Static water resistance (ASTM E331) 2-hour 6.24 psf h. Static water resistance (ASTM E331) 15-minute 8, 10, and 12 psf i. Remove random sections of exterior sealant and repeat static water resistance (ASTM E331) two-hour 6.24 psf and 15-minute tests at 8, 10, and 12 psf j. Structural performance (ASTM 150% design pressure (75 psf) Table 1 Test protocol. ditions, where the sealant installation or maintenance of the joints may be imperfect. LIMITATIONS OF THE TEST METHODOLOGY The test protocol did not include any lateral racking test methods to simulate the effects of interstory drift caused by seismic and/or wind events, and the tested assembly did not include any horizontal panel-topanel joints. LABORATORY TEST RESULTS The following summarizes the laboratory test results. Full test results are available in the test reports prepared by ATI. Structural testing: The mock-up passed all structural testing without evidence of cracking in the EIFS, failure of the panel structure, or any other signs of distress. Air leakage testing: Air leakage rates of <0.01 cfm/ft. 2 (0.05 L/s m 2 ) compare favorably with allowable air barrier assembly air leakage rates of 0.04 cfm/ft. 2 (0.2 L/s m 2 ) per the requirements of the 2012 International Energy Conservation Code (IECC), Chapter 4. 3 Water penetration testing: A leak occurred beneath the window during the initial two-hour water test, with recurrence during the 15-minute static and dynamic tests Water was observed to be leaking into the stud space beneath the window at the windowsill pan fastener locations. The water was observed running down the inside face of the exterior sheathing. The source of this water leakage was traced to sill pan fasteners that penetrated the air/weather barrier coating at the sill (Photo 12). Due to the presence of the interior sealant joint between the sill pan and rough opening, it was not possible during the initial testing to verify if water had leaked through the sill pan itself or through the perimeter sealant joint between the sill pan Photo 12 Water leaking through fastener penetration through air/weather barrier coating at sill. S y m p o S i u m o n B u i l d i n g E n v E l o p E T E c h n o l o g y n o v E m B E r n o r r i S A n d B A r u F F i 1 1 5

8 ADDITIONAL WINDOW INTERFACE LABORATORY TESTING A retest of the static water penetration testing was conducted using a single EIFS panel, the same window, and a single-stage exterior sealant beneath the sill pan to allow further review of the windowsill condi- Photo 13 Sealant removed after testing showing water tion (Photo 14). The leakage into rough opening beneath sill pan. structural attachment of the window and the EIFS. Removal of sealant following was modified for the retest, with the window testing confirmed that water had leaked anchored by clip angles at the jambs and no into the rough opening beneath the sill pan anchors through the sill pan (Photo 15). The (Photo 13). Additional testing was conducted sill pan was connected to the window prior to further evaluate the window sill/sealant to installation of the window into the rough interface. opening. The window manufacturer was contacted to confirm that this anchorage condition was acceptable from a structural perspective. The additional testing was run at a test pressure of 12 psf for a twohour duration, as required for a barrier EIFS system. Prior to test- ing, the assembly was subjected to positive and negative design structural loading of 50 psf for a ten-second duration. During the retest, water was observed to be dripping from the sill pan into the rough opening at the sill pan end dams. This water leak was inboard of the plane of the exterior sheathing. A tracer die was used to confirm that the sill pan itself was the source of the water leakage into the rough opening (Photo 16). There was no leakage through the EIFS system or at the interfaces between the EIFS and the window. The additional laboratory testing confirmed that the source of water leakage was deficient sealing of the sill pan end dams. DISCUSSION The testing demonstrated that the StoPanel ClassicPanelized barrier EIFS provides a watertight and airtight wall assembly. The testing also demonstrated that the dual-stage sealant joints used for the panelto-panel interfaces and for the electrical box interface can provide a watertight assembly, even considering the potential for imperfect installation or maintenance. The water leaks at the windowsill demonstrate the importance of the window system to achieve a watertight wall assembly. The leaks during the wall assembly testing were caused by a poor (although somewhat common) window installation methodology of attaching the window sill pan flashing with fasteners penetrating through the sill pan and rough-opening sill. The leak during the additional window interface testing was caused by a defect with the windowsill pan end dams. Photo 14 Testing of a single EIFS panel. Photo 15 Modified structural attachment with window anchored by clip angles at jamb n o r r i S A n d B A r u F F i S y m p o S i u m o n B u i l d i n g E n v E l o p E T E c h n o l o g y n o v E m B E r

9 The window leaks through the sill pan fasteners in the rough opening beneath the window were a result of window system defects and would not have been mitigated by a drainable EIF system or any other cladding system using the same window anchorage detailing. These leaks demonstrate the importance of proper window system detailing and installation, regardless of the wall system used, and the importance of verifying window system design, installation, and detailing through tests to understand potential leak paths and how they can be eliminated. Further measures could be considered in the structural attachments of the windows and the roughopening detailing at the windowsill to mitigate the risk of leaks due to structural attachment penetrations. Moving all of the structural attachments inboard of the inside edge of the window frame could mitigate the risk of leaks due to structural attachment penetrations. We note, however, that this type of detailing would be considered unusual but worthy of consideration, as normal window industry installation practice can sometimes lead to problems with leaks into wall assemblies. Although thermal modeling was not included as part of the test protocol covered by this white paper, it is worth noting that the EIFS cladding is adhesively attached and does not have any mechanical attachments that would create a thermal bridge. The panelized EIFS provides continuous insulation over a steel stud assembly without any thermal bridges due to cladding attachments. As energy codes become more stringent, the ability to provide continuous insulation without thermal bridging will increase in importance. Photo 16 Water leaking from sill pan; source confirmed using tracer die. Following is a summary of the attributes and benefits of a panelized EIFS cladding: 1. Improved quality control by fabrication in a factory setting 2. Reduced construction schedule and faster dry-in due to off-site fabrication 3. Lightweight exterior cladding system 4. Truly continuous insulation without thermal bridges 5. Durable weather seal and internal air seal provided by dual-stage sealant at panel joints 6. Continuous air barrier with very low air leakage rates 7. Provides a wide range of aesthetic design flexibility Given these benefits, panelization with EIFS that includes mock-up testing of the integrated wall assembly components is a sensible way to comply with today s building code requirements and to meet building owner demands for high-quality construction, nonleaking buildings, and early dry-in of the building enclosure. FOOTNOTES 1. ATI is considered one of the premier exterior wall, window, and curtain wall testing labs in the U.S. and is fully accredited by the American Architectural Manufacturers Association (AAMA) and the International Accreditation Service (IAS). 2. Refer to IBC 2009, Refer to IECC 2012, C S y m p o S i u m o n B u i l d i n g E n v E l o p E T E c h n o l o g y n o v E m B E r n o r r i S A n d B A r u F F i 1 1 7