Correlation of Air Permeability to Other Breathability Parameters of Textiles.

Antonin Havelka,Zdenek Kůs,Karel Adámek,Adnan Mazari

doi:10.3390/polym14010140

Abstract

In the field of textile comfort of smart textiles, the breathability of the material is very important. That includes the flow of air, water and water vapours through the textile material. All these experiments are time consuming and costly; only air permeability is much faster and economical. The research is performed to find correlation between these phenomena of breathability and to predict the permeability based on only the air permeability measurement. Furthermore, it introduces a new way of expressing the Ret (water vapour resistance) unit according to SI standards as it is connected with the air permeability of garments. The need to find a correlation between air permeability and water vapour permeability is emphasised in order to facilitate the assessment of clothing comfort. The results show that there is a strong relation between air permeability and water vapour permeability for most of the textile material.

Highlights

Textile materials used for clothing purposes have been provided with new functional properties to emphasize their improved utility properties for the wearer, that is, in particular, clothing comfort, which means sensory comfort and thermophysiological clothing comfort for the wearer as specified in the definitions of comfort [1]
These definitions clearly highlight the importance of air and water vapour permeability to achieve clothing comfort
This article deals primarily with the problem of evaluation of water vapour permeability according to various standards tested at the Department of Clothing of the Technical University of Liberec

Summary

Introduction

Textile materials used for clothing purposes have been provided with new functional properties to emphasize their improved utility properties for the wearer, that is, in particular, clothing comfort, which means sensory comfort and thermophysiological clothing comfort for the wearer as specified in the definitions of comfort [1]. Thermal comfort is the condition of mind that expresses satisfaction with the thermal environment and is assessed by subjective evaluation [4,5,6,7] These definitions clearly highlight the importance of air and water vapour permeability to achieve clothing comfort. The measurements discussed below determine the volumetric flow rate of gas, which generally depends on its temperature and pressure. It is true that in the laboratory measurements of porous materials the pressure gradient is small, which means the effect of pressure variation on the volumetric flow rate is negligible. When measuring dense and poorly permeable materials, the pressure gradient is larger and the measured volumetric flow rate should be converted into a selected standard state. Variations in the ambient state (barometric pressure, temperature, humidity) objectively affect the actual volumetric flow rate, as discussed below

Air Humidity Effect

Air Flow Rate Measurement

Viscosity Effect

Air Permeability

Theory

Water Vapour Resistance—SGHP Method

Notes:

Hypothesis

Measurement Results