Evaluation of Test Methods To Determine the Impact Resistance of Exterior Insulation and Finish Systems (EIFS)

The use of exterior insulation and finish systems (EIFS) on Army facilities has increased substantially over the past 10 years. The importance of impact resistance in maintaining system integrity to prevent moisture infiltration (a leading cause of system failure), is paramount Army architect/engineers need to know the relative impact resistance of systems so they can specify the correct system for a given use at the lowest cost. Industry-wide standard impact test methods are not available; values reported by EIFS manufacturers cannot be compared throughout the industry. The objective of this study was to evaluate test methods for impact resistance currently being used in industry and determine their validity for use with EIFS on Army facilities. Researchers tested 23 EIFS using the two most common laboratory impact test methods and one field test method. Researchers compared the test results with performance assumptions based on the systems' chemical and physical properties to conclude that the falling ball test is the best of the methods evaluated for assessing the overall impact resistance of EIFS. The results of this research were used to develop a draft standard test method that was presented to the American Society of Testing and Materials.