INFRARED THERMOGRAPHY TO EVALUATE GUASTAVINO VAULTING AT THE WEST SIDE MARKET A thesis submitted to the Kent State University Honors College in partial fulfillment of the requirements for General Honors by Catalina Estrada May 2013 Thesis written by Catalina Estrada Approved by _____________________________________________________, Advisor _____________________________________________, Dean, College of Architecture Accepted by _____________________________________________, Dean, Honors College ii TABLE OF CONTENTS LIST OF FIGURES………………………………………………………………………iv ACKNOWLEDGEMENTS....…………………………………………………………….v CHAPTER I: INTRODUCTION………………………………………………………….1 CHAPTER II: THERMOGRAPHY AND ITS APPLICATIONS…………………...…...2 CHAPTER III: THE HISTORY OF GUASTAVINO VAULTING……………………...8 CHAPTER IV: THE WEST SIDE MARKET…………………………………………...16 CHAPTER V: FIELD STUDY WITH PASSIVER THERMOGRAPHY AT THE WEST SIDE MARKET………………………………………………………………………...21 CHAPTER VI: CONCLUSIONS GATHERED FROM DATA………………………...32 WORKS CITED…………………………………………………………………………34 APPENDIX OF IMAGES.....……………………………………………………………35 iii LIST OF FIGURES Figure 1.1- Archives of Civil and Mechanical Engineering, “sciencedirect.com.” Last modified 2012. Accessed March 12, 2013. Figure 1.2- Maldague, Xavier. Theory and Practice of Infrared Technology for Nondestructive Testing. New York City: John Wiley & Sons, Inc., 2001, 154. Figure 2.1- Ochsendorf, John. Guastavino Vaulting: The Art of Structural Tile. New York City: Princeton Architectural Press, 2010, 55. Figure 2.2- Tarrago, Salvador. Guastavino Co.: Catalogue of Works in Catalonia and America . Barcelona: Collegi d’Arquitectes de Catalunya, 2002, 107. Figure 2.3- Ochsendorf, Guastavino Vaulting, 127. Figure 2.4- Ibid., 147. Figure 2.5- Ibid., 116. Figure 3.1- Twist Creative Inc., “Reacquainting a City with its Public Market.” Last modified 2013. Accessed March 12, 2013. http://www.twist-creative.com/portfolio/west-side-market/. Figure 3.2- Tarrago, Guastavino Co., 78. iv ACKNOWLEDGEMENTS I would like to thank those who supported me throughout this endeavor. To the Honors College, for allowing me this opportunity. To Dr. Robison, my thesis advisor, for his ability to stir my thoughts and interests in the matter. To my defense committee, for giving me valuable critiques and pushing me closer towards excellence. To my friends and classmates, who encouraged me to persevere whenever I had any doubts. To my family members, who always believe in me and support me in whatever work I choose to undertake. To my mother, who helps me to be a strong woman. To my father, who taught me that “only the busy have time.” You were all right, and without you I wouldn’t be where I am today. Thank you, Catalina Estrada v 1 CHAPTER I: INTRODUCTION Infrared thermography is a promising technique for evaluating Guastavino vaulting for the presence of voids and other anomalies. The West Side Market in Cleveland, Ohio will be used as a test case. The current methods used for evaluating Guastavino vaulting involve tapping the surface with hammers and listening for voids. This method is time-consuming and costly. The use of an infrared thermal (IRT) camera to evaluate a Guastavino vault would be quick and inexpensive in comparison to the current expenses necessary to evaluate vaulting. While the scope of this thesis does not permit following up the IRT camera evaluation with a hands-on evaluation of the vault, this thesis aims to demonstrate the ability of IRT imaging to locate anomalies in a tile vault, and provide the incentive to apply potentially cost saving evaluation procedures to Guastavino vaulting in the future. A FLIR T-620 infrared camera will be used to thermally image the vault. Anomalies found in the post-processing of the images will be analyzed and discussed, identifying possible and likely causes for the observed hot or cold spots in the vault. Through a better understanding of thermography and the pushing of its boundaries, this thesis will evaluate the use of infrared imaging in order to demonstrate its promise to be a time-efficient and cost-efficient way to check for anomalies in Guastavino vaulting. 2 CHAPTER II: THERMOGRAPHY AND ITS APPLICATIONS The first quantification of temperature was accomplished by Galileo in the year 1593, with the invention of the first glass thermometer. 1 At the time of this invention, however, the science of temperature was not completely understood. It would take a couple centuries before the science was better comprehended. Infrared rays were discovered by William Herschel in the year 1800, when he used a prism to protect his eyes while observing the sun, after having accidentally discovering the planet Uranus. After this discovery, the doors opened for an array of studies and discoveries in this field, allowing for a greater understanding of temperature.2 Thermography is the study of temperature distribution and is used as a nondestructive testing method in the analysis of buildings and electromechanical systems. The science of infrared imaging is used to check the thermal qualities of specific surfaces during the performance of building diagnostics.3 By observing the surface temperatures of building elements subjected to a heat flux, internal structures of the elements can be revealed in the surface temperature pattern. 1. Maldague, Xavier. Theory and Practice of Infrared Technology for Nondestructive Testing. New York City: John Wiley & Sons, Inc., 2001, 4-11. 2. Maldague, Theory, 4-11. 3. Ibid., 1. 3 There are several different thermography procedures that can be applied to buildings. They include passive methods and active methods (Fig. 1.1). Passive methods use the first law of thermodynamics in conjunction with the collection of temperature Figure 1.1 Diagram of passive versus active differentials across a surface. Heating thermography sources are ambient sources, such as sunlight, or building heating and cooling cycles. Active methods apply energy to the surface being tested in order to capture more drastic temperature differentiations. The energy being directed at the surface can differ in the length of the pulse when using active thermography. The temperature field can also be recorded based on the variance of time between the input and the output of energy. Another form of active thermography is vibrothermography, which induces mechanical vibrations to the surface through direct contact, and measures the heat being released at defective locations in the material.4 Given the size of the West Side Market, using active thermography techniques where heat is applied to the building is not a practical means of evaluating the Guastavino vaulting in the West Side Market. Passive thermography will be the more practical technique in order to gather information on temperature differentials of the vault without 4. Ibid., 1-3. 4 having to directly access the surface. 5 Instead of relying upon the direct application of heat or energy as done in active thermography, the building heating system will be the source of the heat flux, as the exterior temperatures in the 20°’s and 30°’s create a strong temperature flux through the vault to the cold attic above. These surface temperatures on the vault which result from the temperature differential between the conditioned space and the attic will then be analyzed to determine where there are air leaks in the ceiling, where delaminations between tile layers impede the heat flux, and where moisture infiltration causes cooling of the surface through evaporation. Passive thermography deals with locating hot spots on an object or material. Hot spots are the ∆T’s, or temperature differences, that are picked up by the infrared camera. These hotspots are generally a few degrees off from the surrounding temperatures. Passive thermography methods are typically considered to be of a qualitative nature, since it is usually used to locate abnormalities in an object or surface, but the use of passive thermography to locate temperature differentials on the ceiling of the West Side Market will be a quantitative study as well.6 By scanning the vault of the West Side Market in varying conditions, it is eventually hoped to develop practical guidelines for obtaining the optimal information from IRT scans of tile vaults. 5. Rosina, Elisabetta, and Elwin C. Robison. “Applying Infrared Thermography to Historic Wood-Framed Buildings in North America.” APT Bulletin. 33. no. 4 (2002), 38. 6. Maldague, Theory, 1. 5 There are three main benefits of using infrared technology. The first is that surface temperatures are denoted based on the actual temperature that the surface is experiencing at that exact moment. The second is that infrared images can be taken from a distance without the need of scaffolding. The third benefit is the time-efficiency provided by being able to cover large areas at a time through one image.7 Sometimes the optical science behind thermography can reduce the accurate reading of infrared imaging (Fig. 1.2). Aberrations caused by the type of lens used or the way in which it was used can degrade the image Figure 1.2 Diagram of a thin lens used in being studied. Spherical aberrations in lenses infrared cameras with curved surfaces are caused when rays both close and far from the optical axis are being focused at different points. Coma aberrations are caused by light passing obliquely through a lens in a comet-like fashion across the optical axis. Astigmatism aberrations are caused by cameras not being able to produce a plane object into a plane image. The edges of the image are blurred when the image is shown on a flat screen due to the curvature of the field. Distortion aberrations may occur when trying to correct or limit spherical aberrations in lens. Vignetting aberrations may occur when the lens aperture is reduced, causing images with darker edges.8 When analyzing an image, aberrations such as these 7. Rosina, Robison, “Applying.” 38. 8. Ibid., 160-161. 6 should be taken into consideration to better understand what is happening on the surface or material being studied. Passive thermography has been used in the construction industry for decades. In the 1970’s, as building standards became more developed, thermal loss was studied with infrared cameras.