Structural Insulated Panel Testing
In an effort to more fully develop and analyze structural insulated panels (SIPs) as a high performance, energy efficient building system, FAS has conducted several different tests to evaluate their performance. This includes fire, earthquake, and missile testing.
FAS has worked with Professor Khalid Mosalam, an expert in concrete and masonry structures, fracture and damage mechanics and earthquake engineering at Berkeley’s Department of Civil and Environmental Engineering, to conduct a comprehensive test on SIPs with varying facings, connections and insulations to determine their seismic performance. The work was carried out at the Pacific Earthquake Engineering Research (PEER) center located at Richmond Field Station at the University of California, Berkeley is a leader in simulating the performance of buildings through its Open System for Earthquake Engineering Simulation (OpenSees) program. OpenSees is an advanced performance simulation software framework that integrates structural behavior, soil and foundation behavior, and damage measures.
Based on the results obtained from these tests, Prof. Mosalam gave a presentation at the ASCE AEI Conference in 2008 and has, with FAS, authored two papers on the seismic performance of SIPs.
Seismic Evaluation of Structural Insulated Panels. This paper was written by Khalid Mosalam and co-authored by Joe Hagerman and Henry Kelly of FAS. The paper focuses on the characterization of the mechanical properties and seismic performance of SIPs using experimental techniques. Specimens studied include both OSB faced and cementitious SIPs, where panels were tested without panel-to-panel connections.
In early 2004, FAS partnered with the Southwest Research Institue in San Antonio, Texas to test the stability and safety of SIP panels when exposed to flames and high heat for extended periods of time. Two tests were run. The first test, as specified by Uniform Building Code Testing Standard 26-3, was intended as a basic comparison of the panel’s performance to the performance of other materials also used in building applications. The standardized test also served the purpose of completing the certification of the material for use in the United States. The second test was intended to demonstrate the safety of the material during a fire when the oxygen supply to the fire was increased and when the structural integrity of one of the panels directly exposed to the flames was weakened before the fire. This test was accomplished by adding a window cutout in one of the panels that formed the corner where the fire was built.
The panels passed the first test with minimal, superficial damage. The fire, which reached temperatures of over 1000ºC at points three feet above the floor and 250ºC at the ceiling, did not spread to the walls or outer extremities. The EPS foam melted away at the points exposed to the extreme heat, but did not ignite at any time. The panels also successfully passed the second test, with damage similar to that seen in the first test. The most significant difference from the first fire test was the damage in the area under the window frame. The number and surface area of exposed joints, which were unsealed at the point where the cement board skin intersected the wooden window frame, was much greater than in the previous test.
As a result, there was a significant increase in the loss of foam under the window frame. Smoke production from each test was minimal. As a result of this testing, these concrete SIPs were certified as meeting the requirements of most building codes in the United States as defined by UBC 1997.
Strong hurricanes that devastated the Gulf Coast highlighted the need for safer, more efficient structures that are also affordable in the region. FAS, a proponent of safer and more efficient buildings, sees the quest for alternative methods as an opportunity to showcase the versatility and strength of Structural Insulated Panels (SIPs) while fulfilling energy efficiency goals. FAS has collaborated with the Institute of Business and Home Safety (IBHS)’s Fortified…for safer living program and the University of Florida Laboratories in Gainesville to perform projectile tests to understand and document how SIPs with fiber-cement facings tolerate wind-borne debris that is all too common in hurricane-prone areas.
The testing took place on Tuesday, December 12th at the University of Florida laboratories in Gainesville under the supervision of Fortified engineer Dr. Tim Reinhold and Dr. Kurt Gurley. The test procedure called for a 9-pound 2×4 to impact the panel at 34mph. The testing specimen comprised of CSIPs with 7/16-inch-thick skins. Of the three panels that were tested, only the density of the foam core varied. According to Dr. Reinhold’s observations, the panel with 2lb density core showed no cracking on the inside surface at 34mph. The threshold for penetration was observed at 35mph for the panel with the 1,5lb foam density. Finally, the third specimen with 1lb core passed the test despite showing cracking at 34mph. The impact test also proved it possible to attach commercially available shutters to panels to protect window openings, which is a prerequisite for obtaining a Fortified certification.