An investigation of thermal comfort properties of abaya under heat stress

<p>Abaya is a black outer garment worn by women in Saudi Arabia when they are outside their homes. It is designed to cover the whole body. It may be worn either from shoulder or from the top of the head and reveals only the face, feet and hands. Abaya absorbs heat from sunlight in a hot climate, as it is black, making the wearer very uncomfortable. In addition, the multiple layers of clothing within the abaya add more thermal stress.</p><p></p><p>The present research aims to obtain an overview of the type, variety and comfort of abaya worn by women in Saudi Arabia. This was used in identifying the textile materials for abaya and understanding the comfort factors of the wearers. The outcome was used to understand and improve the thermal comfort performance of the traditional abaya.</p><p></p><p>A survey was undertaken to obtain the opinion of women in Saudi Arabia regarding the problem of thermal discomfort of current abaya. The key points considered were the type of fabrics and designs being used and the degree of perceived comfort. The survey showed that the discomfort affects a specific type of clothing. It also revealed that the current abaya when worn over multi-layers of inner clothing was thermally uncomfortable.</p><p></p><p>Objective evaluations of the thermal performance of abayas, made from the commonly used woven and knitted fabrics were carried out using various standard tests. Thermal comfort properties were determined based on thermal resistance, air permeability, and vapour resistance. The results indicated that the fabric structure (woven or knit), fibre composition, fabric weight and fabric thickness greatly influence the fabric thermal comfort performance. It was found that woven abaya fabric is more comfortable than knitted.</p><p></p><p>A female sweating thermal manikin was utilized to evaluate physical properties related to the heat transfer and moisture management properties of abayas.  This was conducted in combination with daily wear clothing, including underwear, skirt / pants and shirt, with abaya and scarf, as worn in Saudi Arabia. The thermal and evaporative resistances of clothing worn within the abaya were measured. The results could contribute to the improvement of abaya design so as to minimize thermal and evaporative resistance in a hot environment.</p><p></p><p>In order to improve the comfort properties, woven fabrics were dyed in black and treated with an Energy Reflecting Chemical (ERC), so as to reflect heat from the environment, in particular solar energy. This would aid in keeping such fabrics cooler. The fabrics were evaluated to assess the thermal comfort properties. The degree of comfort depends not only on the type of fabric and design but also on the clothing worn underneath. Most of the abayas were made from woven fabrics that masked body contour. Synthetic fibres (polyester) were used prevalently because of its easy care feature. It is evident that the lightweight and thinner satin fabric is most suitable for abaya and can provide better handle and thermal comfort in a hot environment. In addition, the results showed that ERC marginally improved the thermal comfort properties under the current experimental conditions. Moreover, it was found that the ERC lowered the temperature of the surface fabric between 0.9 - 1.8 °C.</p>