Test Method Development for Outdoor Exposure and Accelerated Weathering of Vinyl Siding Specimens

Abstract

This chapter provides an overview of extensive research conducted by the Vinyl Siding Institute (VSI) on the development of new test methods for exterior plastic building products. The purpose of the VSI study was to develop an accelerated testing protocol for use in certifying materials.

This chapter describes the development of an outdoor certification test program and subsequent efforts to create an accelerated weathering test method that could be used to predict the results of the outdoor protocol with a high degree of accuracy. Outdoor weathering tests were conducted in Florida, Arizona, and the northern temperate locations to obtain baseline data for comparison. This part of the research led to the development and subsequent publication of ASTM D6864.

Accelerated laboratory tests were performed in Fluorescent UV/condensation test apparatus and xenon arc test chambers. The process involved the examination of multiple types of equipment, multiple cycles, and multiple conditions, and comparing the various results to the outdoor exposures. Testing suggested that for this particular material, one method was more suitable than the other. The proposed method was verified with repeat testing and rugged statistical analysis. Round robin testing was conducted to determine repeatability and reproducibility.

Although the proposed accelerated method was not adopted into the VSI’s certification program, its results demonstrated high rank-order correlation with outdoor test results, giving the user much greater confidence that materials passing the accelerated test will pass the outdoor test. The accelerated method, therefore, is useful during research and development because it provides a fast and reliable method for evaluating small formula changes. It is useful for selecting formulations to include in a 2-year certification test.