Evaluating the Potential Use of Highloft Nonwoven Fabrics for Rain Gutter Applications

Abstract

The behavior of fluid flow is an important criterion for nonwoven fabric design and in their applications such as filtration, insulation, geotextiles, geomembranes etc. Highloft nonwoven fabrics are thick, highly porous and bulky, unlike other nonwoven materials. As a result of their structure, these fabrics exhibit both transplanar and in-plane flow capability.

This study is exploring the potential application and utilization of highloft fabrics in rain gutters instead of 'costly' alternatives such as gutter guards, screens etc. For this study, a new testing device was developed to examine the volumetric flow rate of water through, and volumetric flow efficiency, of different types of highloft fabrics under different conditions. The testing device was named 'Rain Machine' since its purpose was to simulate rainfall effect on a particular size of roof and rain gutter. Also by making a minor modification to the NCRC GATS Absorbency Test System, the drainage time and conditions of the fabrics were examined.

In this study, the experimental work is carried out by focusing on the macrostructure of the highloft nonwovens rather than the microstructure. In addition to this, two different kinds of foam material were utilized to determine whether there is any improvement of the volumetric flow rate or not. It was visually found that no microorganism activity occurred by the end of the three-week continuous testing, but structural changes such as loss of loft was significant.

A statistical approach to experimental design and analysis of these research findings was necessary to draw meaningful conclusions from the data obtained. ANOVA statistical method was used to analyze the experimental data and multiple comparisons carried out using Tukey's pairwise comparison method.

From these analyses, the flow rates for the unsaturated fabrics were found to be less than that of saturated. However, using different kinds of foam materials did not affect the flow rate significantly. The data for black foam material, which had 20 pores per inch, showed a practical difference, but no statistically significant difference due to gravitational forces which caused the fabric to clog the drain spout and made flow of water harder. The data for yellow foam material, which had 90 pores per inch, showed that its water flow rate was the lowest, however, results were not significantly different than that of black foam material.