Solar protection Effect of selected fabric and use characteristics on UV transmission

Transcription

1 Solar protection Effect of selected fabric and use characteristics on UV transmission C. A. Wilson, ) N. K. Bevin ) B. E. Niven ) and R. M. Laing ) ) C. A. Wilson is a Senior Lecturer, N. K. Bevin an Honors student, and R. M. Laing a Professor in Clothing and Textile Sciences; ) B. E. Niven is a Consultant with the Centre for the Application of Statistics and Mathematics. University of Otago, Dunedin, New Zealand Abstract Corresponding author C. A. Wilson Lecturer, Clothing and Textile Sciences University of Otago P. O. Box Dunedin New Zealand c.wilson@otago.ac.nz PH + 9 Fax Clothing is worn in single and multiple layer arrangements and during use subjected to conditions such as extension and wetting. This study investigated how selected variables affected transmission of ultraviolet radiation (UVR) through fabrics and whether these variables interact to modify transmission. Using a spectrophotometer the effect of: i) fabric type (two knitted, two woven), color (black and white), wetness (dry, wet, damp), and extension (relaxed, extended (x%, x%), and ii) fabric type and layering (,, layers) of white fabrics, on UVR (9- nm), UVA (- nm), UVB (9- nm), and ultraviolet protection factor (UPF) rating was investigated. Differences among variables were identified using univariate and repeated measures ANOVA and interactions among variables identified and described. Selecting dark colors, limiting extension and layering fabric are shown to be effective ways of increasing UV protection and UPF by decreasing transmittance. However, the effect of color, extension and layering varied among fabric types and modified UVA and UVB transmittance differently. Key words: (-) structure, layers, color, extension, wetness, interaction Introduction Clothing has long been recognized as an effective means of photoprotection with wearing clothing recognized as a means of modifying UV exposure [, ]. Consequently the focus of much research has been to examine fabric characteristics (such as fabric structure [,, ], thickness [], weight [], fiber type [, 8], fabric extensibility [, 9,, ], wetness [,, 9,, ]), and finishing treatments (such as UV absorbers [] and coloration (dyes) [,, 9]) which modify transmission. In addition, when worn fabrics are commonly subjected (among other things) to extension and wetting, and are arranged in multiple layer configurations. Use thus has potential to modify a fabrics protective capacity. To date investigations have generally been limited to study of single-layer specimens [, ], predominantly using laboratory testing (rather than wear testing of fabrics made into garments), and with small sample sizes. Examination of interactions among variables of interest has generally not been possible. Given that products may be worn in single and multiple-layer combinations, and with interactions among variables likely, there is a need to assess both the effect of factors, and interactions among these factors, on UVR transmission and UPF rating and to understand how variables modify the UVA and UVB parts of the spectrum. Understanding how fabric properties and conditions of use affect transmission will aid optimization of protection by enabling manufacturers, designers and users to select the most effective combinations of variables. In this current investigation the effect of a) fabric type, color, extension and wetting, and b) fabric type and layering, on UVR, UVA and UVB, and UPF was investigated, and whether interactions among variables have a modifying effect on UV transmission was examined. Fabric structure and color have been proposed as the most important variables [,, ] affecting UVR. The effect of fabric structure (e.g. woven or knitted) has been related to the cover of woven, or gauge of knitted, fabrics [, 9] with tighter or closer structures associated with fewer 'holes' in the fabric and thus less transmission [9, ]. Fabric effects have also been linked to: the degree of cover/interstitial space present in a particular fabric; fiber type [, ]; structure [8, ]; and/or

2 thickness []. However, with a few exceptions (such as the work of Riva and Algaba [] who controlled fiber and yarn variables) fabrics investigated have generally not been matched for processing variables and/or experiments have not been designed to enable the causal relationship among variables to be clarified. Consequently, there is some inconsistency in the published literature about the relative importance of fiber and fabric variables in terms of modifying transmission [,, 8,, 8] and the mechanisms responsible for the effect. In the case of color, 'dark' colors (such as dark green, red, navy blue, black) are reported as providing better protection than 'light' colors [,, 9, 9], possibly due to dyes absorbing radiation and modifying transmission differently. For example, due to dyes absorption spectrum overlapping with the UV (predominantly UVA) part of the spectrum [9, ], and/or due to differences in the way the dye interacts with different fiber types [] consequently modifying the physical, performance properties of the fabric. Other processing treatments may also affect transmission. For example, inclusion of bleaching processes (e.g. by removing naturally occurring pigments and lignin's which act as UV absorbers) as does introduction of optical brightening and fluorescent whitening agents [, 9,, ]. Wear effects such as wetting [,, 9,, ], extension [, 9,, ] and layering [] are also known to modify transmission however whether these effects are modified by other manufacturing choices such as fabric type, color, etc is not known. Method Four fabrics, two knitted and two woven (each available in both black and white so fabric 'sets' were matched), were evaluated (Table a). The effect on UVR, UVA, UVB and UPF of: a) fabric type, extension (nil/relaxed, x% and x%) and wetting (dry, damp, wet) was investigated using single layers of black and white fabrics, and b) the effect of fabric type and layering (, and layers) was investigated using white fabrics only (as all fabrics were highly protective and even one layer of black fabric was associated with maximum protection). Prior to characterization and testing, fabrics were washed in color batches to prevent cross-dye contamination [] and line dried three times []. Cotton fabrics were pressed using a domestic iron according to the manufacturers instructions. Fabrics were spread and rested for hours prior to cutting with fabric specimens (mm x mm; n= for each fabric and variable combination) then cut randomly from each fabric after the area within mm of the manufactured edge was discarded. Specimens were labeled with warp/wale ( ) and weft/course (9 ) yarn orientation to facilitate accurate placement during UV testing []. All specimens were conditioned at ± C, and ± % R.H., for hours prior to testing [] and tested under these conditions where possible. The order of testing was randomized. As measurement of UV transmittance and interstitial space (described below) were not carried out in controlled environments, each specimen was first conditioned, then transported in individual re-sealable bags to maintain the specimens as close to standard conditions as possible. Each specimen was removed from the bag only as required for testing. Fabric UV characteristics [], mass per unit area [], thickness [8], and percent of interstitial space were described (Table b). Percent of interstitial space was determined using an Olympus AX 'Provis' transmitted light microscope, a Spot RT real time color digital camera and a personal computer installed with image analysis software [9]. Conditions in the microscopy area were not controlled but were monitored during each measurement session. Five randomly selected areas from the technical face, and five from the technical rear of each specimen, were imaged (J-PEG quality = ). The mean interstitial space for both the technical face and technical rear were calculated and then averaged to determine the overall percent interstitial space for the fabric (Table b). Two- and three-layer specimens (technical face uppermost and orientation matched) were diagonally basted together (color matched, % polyester thread), to minimize the space between layers. Dry specimens received no treatment prior to testing while 'damp' and 'wet' specimens were wet with distilled water to an additional % and % of their dry mass per unit area respectively, then stored into individual airtight, re-sealable plastic bags under standard conditions for hours. Pre-testing showed change in weight and therefore change in moisture level was negligible prior to and during testing. UV transmission was evaluated under conditions of no fabric extension (i.e. relaxed) and when extended in the warp/wale and weft/course by x% and x%. The extension apparatus was designed to hold the extended fabrics in position for measurement while still allowing rotation of the holder thus facilitating measurement in the and 9 orientations. Each specimen was first measured in a relaxed state with no extension, then extended by x%, and then by x%. UV transmittance was determined at nm intervals using a spectrophotometer, according to the method specified in AS/NZS 99 []. A Cary diffuse reflectance accessory was used to measure transmittance over a wavelength range of 8-

3 nm, and consisted of a mm diameter integrating sphere, fitted with a Schott-UG filter (to minimize measurement error caused by fluorescence) and holder. The technical face of the fabric was positioned outward towards the UV beam source. Bubbles and/or wrinkles that were not an inherent characteristic of the fabric, were eliminated. Temperature and relative humidity of the testing environment were not controlled but were consistent with that specified by AS/NZS 99: 99 (ambient temperature and humidity ranges were ± C, ± % R.H.) []. Percent transmission of UVA, UVB and total UVR for each variable and level were calculated according to AS/NZS 99: 99 []. Data were then described (mean, standard deviation (s.d.)). To determine whether UVR transmission and UPF were affected by i) fabric type, color, extension, and wetness, and ii) fabric type and number of layers, factorial ANOVA of UVR and UPF data was undertaken []. The effect of factors on UVA and UVB was investigated using repeated measures ANOVA [, ]. Where significant differences among means were identified Tukey's multiple comparison tests were applied to identify relationships among factors []. Results and discussion Part A Effect of fabric type, color, extension and wetting single layer fabrics UVR transmission and UPF through single layers of the fabrics ranged from.9% (UPF=9) through the black, dry, relaxed piqué to a maximum of.% (UPF=9) through the white, wet, extended eyelet fabric. The black twill afforded excellent protection with no transmission detected, however, while the protection offered by this fabric is of note, missing data meant the twill fabric was excluded from further analysis. Fabric type had the greatest effect on UVR transmission (F, =., p<.) with all fabrics affecting transmission differently []. Most UVR was transmitted through the eyelet fabric (.%) with less through the plain weave (.%), and least through the piqué (.%)(Figure a). Differences were consistent with the percent of interstitial space present in each fabric and inversely related to mass per unit area (Table ). While each fabric in the current study were matched for color (i.e. black and white pairs), other processing variables differed among fabric types and were not controlled, thus it is not possible to confidently attribute differences to structure or fiber type. However, the double jersey eyelet modification structure of the eyelet fabric had the highest transmission and interstitial space, second only to that of the white piqué while the plain fabric with lowest transmission was also the thinnest. Reasons for the associations between physical properties and transmission were not however obvious and possibly reflect interactions between fiber type and structure. Fiber type is known to affect UV transmission with differences in absorption occurring among fibers, e.g. cotton transmits less than other natural fibers [] while polyester absorbs strongly in the UVB region []. Riva and Algaba [] showed transmission (UPF) through plain weave fabrics was affected by 'structural' effects in the form of variations in tex and yarns per cm with cotton and that Modal fabrics were less sensitive to variations in structural effects than Modal Sun fabrics. Extension was the second most important influence on UVR transmission (F, =9.9, p<.)(figure b) with the effect of extension varying slightly among fabrics (F, =., p<.)(figure a). Differences among fabrics is not unexpected given extension capacity is in part due to the structure of the fabric (i.e. knitted fabrics have an inherent capacity to extend while woven fabrics do not), and in part due to the fiber composition (e.g. inclusion of elastomer fibers enhance extension capacity) []. Differences among fabrics may also reflect differences in the cover offered by different structures during extension. Moon and Pailthorpe [] showed mean extension in garments made from fabrics including elastomer fibers ranged from to % ( X = %). Thus, extension levels investigated in the current study are consistent with those likely to be designed into garments during product development and that experienced during use. Findings highlight the range of extension levels likely to occur among structures and fibers and the potential for claimed protection capacity to be modified by use [, ]. Color is generally accepted as an important variable affecting UV transmission [,, 9, ]. In this current study where black and white fabrics (otherwise matched for manufacturing variables) were compared, color was confirmed as significantly influencing transmission (F, =9., p<.). Black fabrics ( X =.8%) generally transmitted % less UVR than their matched white equivalent ( X =.%; Figure c). Results suggest that further processing of the white fabrics in the form of dyeing them black may be associated with desirable changes in UV transmittance. Coloring the white fabrics black was generally associated with an increase in mass, reduced thickness and smaller percent interstitial space (Table b). However, while significant (F, =8., p<.), percent differences in transmission among the fabrics examined here were sufficiently small to suggest the main effect on UV may be due to the dye rather than due to differences in fabric properties (Table b). Findings support recommendations that manufacturers seeking to supply fabrics that are more protective should select dark colors that minimize UV transmission. Color may also be used to modify the effect of other variables. For example, color modified the effect of extension (F, =.8, p<.; Figure b) with extension having a smaller influence on UV

4 transmittance through black than white fabrics. This difference may be due to the effect of the dye on the physical properties of the yarn and thus due to changes in the performance characteristics of the yarn. Wetting fabrics has been identified as one of the principal variables modifying transmission [, 9, ]. However, over all color and fabric combinations assessed in the current study moisture level did not generally affect UVR transmission (F, =., NS; Figure d) possibly reflecting the polyester fiber content of the fabrics. However, a small but significant change in transmission was identified for some of the fabric types evaluated (F, =., p<.; Figure c) indicating wetting did have an affect which depended on the fiber/fabric type and the degree of wetting. The effect of wetting has been attributed to water present in the interstices reducing optical scattering with associated increased transmittance [,, ]. Both fiber and fabric type will affect how water is held in the structure []. In the fabrics investigated in this study transmission through the % polyester eyelet and plain weave fabrics were associated with negligible change in transmission when damp (as expected in hydrophobic fabrics which are not subject to fiber swelling). However, transmittance through the dry piqué fabric (with hydrophobic and hydrophilic faces) decreased by % when fabrics were damp while wetting the fabric resulted in only a negligible change in transmission from that when dry (.% wet;.9% dry). The two faced plated piqué fabric may have been affected by fiber swelling and associated reduction in the number and size of pathways through the fabric on the hydrophilic face i.e. decreased free water and increased scattering on the hydrophilic face when damp, and wet []. In contrast the decreased transmittance through the plain weave % polyester fabric when wet (% less than the dry value) is more likely to reflect the effect of structure and thus the size and orientations of interstitial space on how water is physically held in the fabric. Wetting of a selection of extended, mainly polyamide/elastane and cotton/elastane fabrics has previously been reported [] to decrease UPF and by implication modify UVR transmittance. In the current work where fabrics were generally polyester or polyester blend no such interaction between degree of wetness and extension was found (F, =., NS). UVA and UVB The type of fabric, color, extension and wetness affected the percent of UV transmitted in the two regions of the spectrum differently (F, =., p<.)(figure a-d). As expected UVA transmission through fabrics was consistently greater than UVB. However, color had a greater effect on UVA transmission than UVB (F, =88., p<.) reducing UVA transmission (depending on fabric type) by % to -% when the white fabrics were dyed black (UVB changed from % to only -%)(Figure d). Such an effect is consistent with differences in absorption of radiation according to the part of the dyes absorption spectrum which overlaps the UV spectral region []. The effect of color on UVA and UVB transmission also varied depending on the fabric (F, =8.8, p<.). The greatest reduction in UVA transmission occurred in the plain weave (-%) and in UVB in the piqué (-%)(Figure d). Effects attributed to fabric type may be due to variables such as fiber type, structural effects [], cover factor [, 9] and/or thickness []. Understanding the specific aspects of fabric type affecting transmittance is important if UV protective properties of fabrics are to be optimized. Extension had a greater effect on UVB than UVA transmission (F, =., p<.) with proportionally greater changes in transmission of UVB and UVA in some fabrics than in others (F, =., p<.)(figure a). While the most transmission with extension occurred in the eyelet fabric, the greatest percent change occurred when the plain fabric was extended by x% (i.e. a % increase in UVB and % increase in UVA transmission). How fabric variables affecting extension (such as structure) modify transmission requires further investigation. For example, it is apparent that the effect of extension in the UVA and UVB parts of the spectrum varied depending on the color of the fabrics (F, =., p<.). Extension increased UVA and UVB transmission similarly but with the effect being marginally greater on UVA in Black fabrics, and on UVB in white (Figure b). Wetting also increased transmission in the UVB more than in the UVA parts of the spectrum (F, =.8, p<.)(figure c). However, the effect of wetting on UVA and UVB parts of the spectrum did not vary according to the type of fabrics (F, =., NS). UPF Extension, fabric type, and color modified UPF rating. However, the order of importance of these variables differed from that identified when examining UVR transmission reflecting: i) differences in the effect of these variables on the UVA and UVB parts of the spectrum, and ii) the weighting of UVB when calculating UPF in order to reflect the erythemal action spectrum developed by Commission Internationale d' Eclairage (CIE) [, 9]. The greatest influence on UPF was extension (F, =99., p<.) with the effect of extension varying among fabrics (F, =.8, p<.)(figure ). Decreases in UPF of % with % extension have been reported by Pailthorpe and Curiskis [] and changes in UPF of stockings with increasing extension reported by Kimlin et al., [], yet to date any potential relationship between fabric structure and extension has not been clarified. Degree of fit and by implication

5 extension level has also been shown to affect level of UV transmittance during use []. Results from the current work confirm the fabric specific nature of differences. As a result of extension cover decreases and UV transmission increases [, ]. Extension by x% resulted in - to -% reductions in UPF. However, the greatest reduction in UPF occurred with the first level of extension (x%: - to -%). Transmission through the very extensible eyelet fabric did not differ between the two extension levels, possibly due to extension expanding the size of the fabrics 'eyelets'. Fabric type was the second most important influence on UPF (F, =.9, p<.). While rated as providing excellent protection when measured dry and relaxed [] the fabrics provided significantly less protection over all variables (e.g. dry, white, eyelet with maximum extension UPF = 9). Findings confirm the importance of considering how products will be finished and used. All variables influenced UPF of the fabrics differently. Generally, mean UPF of black fabrics was approximately % greater, i.e. more protective, than white fabrics (F, =., p<.), a finding consistent with that of Wang, et al., [9] who found navy blue dye was more effective than light yellow at reducing transmission. Color of the fabrics also affected UPF differently according to the fabric types (F, =.9, p<.) possibly reflecting differences in: i) how the fabric was affected by the dye e.g. physical properties of the fabrics such as thickness, mass and percent of interstitial space were modified (when fabric was dyed black)(table ), and ii) how dye and fabric variables modified transmission of UVA and UVB. Further work to clarify how dye affects fiber and fabric characteristics and thus UPF is recommended. While the change to UVR was small in the high UPF fabrics included in this study, interactions among variables and differences in the way they affected UVA and UVB transmission confirm the importance of understanding more precisely how variables and combinations of variables affect transmission. For example, extension had the greatest effect on the piqué knit and plain weave fabrics increasing UVR by % and % respectively. While total UV through these fabrics was still comparatively low (%), garment design choices and wearing conditions have the potential for reducing (or maintaining) their actual protective capacity during use. Findings support the proposal that UPF claims may not represent the protective capacity of fabric during use [] and suggests that when protective capacity is stated, consumers also need to be aware that conditions of use such as wetting and extension may decrease protection []. Part B Effect of fabric type and layering on UV transmission through white fabrics Transmission through multiple layers of fabric was investigated for white fabrics only, as addition of a second layer of matched fabric to black specimens reduced transmission to such an extent that only the default minimum transmission was recorded. The number of fabric layers and the type of fabric were the most important influences on UVR transmission (F, =., p<.; F, =., p<. respectively). As the number of layers increased, transmission decreased from a mean calculated over all fabrics of.% through one layer of fabric to a mean of.% through three layers of fabric (Figure ). Transmission decreased significantly with each additional layer (Tukey HSD []). Fabrics (i.e. mean transmission calculated over all layer combinations) formed three distinct groups within which transmission did not differ significantly. The greatest overall transmission occurred through the eyelet knit fabric (.%), lowest transmission through the piqué knit (.%) and twill weave fabrics (.%) which did not differ significantly from each other, while the twill and plain weave fabrics formed a third intermediate group (. and.9%). The effect of layering varied among fabrics (F, =., p<.). The greatest effect of layering was to reduce transmission through the piqué, twill and plain weave fabrics by -% to -%. In comparison addition of a second-layer reduced transmission through the eyelet fabric by only - % consistent with the open nature of the structure. Transmission through three layers of fabric was reduced from that through one layer by -8% to -8% with little difference attributed to the type of fabric. UPF of the fabrics was, as expected, affected by (in order of importance), i) the number of layers, and ii) the type of fabric being layered (F, =8.8, p<.; F, =9., p<. respectively). The effect of layering varied among fabric types (F, =.9, p<.; Figure ). Lower UPF values for the various fabrics and layers generally reflected the pattern of UVR transmission through the fabrics, i.e. higher UVR associated with lower UPF values. The highest UPF values were for the plain weave followed by the piqué and eyelet knit fabrics and the lowest UPF for the twill weave fabric. The twill fabric (which exhibited a UVR transmission value intermediate between the piqué and plain fabrics) was associated with the lowest UPF value over all layers. The differences in UPF reflect differences in the way the fabrics modified UVA and UVB transmission (F, =., p<.)(figure )[]. Differences in UVA and UVB transmission occurred as a result of layering, with differences being fabric specific (F, =9., p<.)(figures ). Both the eyelet and twill fabrics exhibited comparatively higher UVB transmission rates, and thus lower UPF values. Layering proved to be a more effective barrier to UVB than UVA (transmission between and layers was reduced by 8% to 8% for UVB, and -% to -% for UVA)(F, =., p<.). Thus layering proved to be an effective means of increasing protection.

6 Conclusions Fabric specific properties modify UV transmission. When the relative importance of variables such as fabric type, extension, wetting and color are examined concurrently, fabric type was identified as the most important variable affecting transmission. Fabric type is likely to modify UV as a result of structural and fiber type differences with interactions between fabric structure and fiber content likely. Extension, color and layering also affected transmission with their effect commonly varying among fabric types. Transmission was also affected by interactions between other variables. For example, the effect of extension varied between colors. Further work is required to understand the mechanism affecting UV transmission with results suggesting it may ultimately be possible to optimize protection by selecting specific structure, fiber and finishing combinations which maximize protection for selected conditions of wear. Differences in protection as a result of layering and coloration also illustrate the importance of understanding the relationship between processing/product development and protection. For example, manipulation of order and type of finishing and/or developing designs that utilize layering may prove to be effective means of optimizing protection. Extension and layering also modified protection illustrating the importance of considering the effects of fit and design both when developing and selecting clothing. Variables modified transmission in the UVA and UVB parts of the spectrum differently. For example, the main effect of color was on the UVA part of the spectrum while wetting, extension and layering had the greatest effect on UVB transmission. Such differences may have implications in terms of claimed protection from UVR as expressed by the calculated UPF value. UPF is weighted to reflect the erythemal action spectrum developed by CIE, and so may not accurately reflect changes in UVA transmission. As a consequence, when evaluating changes in protective capability resulting from manipulation of fabric manufacturing specifications UVA and UVB transmittance should be measured. If UV exposure of the body is to be minimized the importance of design and wear decisions (fit, color, layers) should be promoted in addition to promoting the need for appropriate selection fabric types and colors. Acknowledgements The support of the following is gratefully acknowledged: The Chemistry Department, University of Otago, for access to the Cary spectrophotometer; Dr J. Webster for preliminary review of literature and sourcing of fabrics; Dr D. J. Carr, for her assistance with identification of selected fabric characteristics.

7 Table Description of fabric structure, fiber content and selected physical characteristics (new dry fabrics) Variable Eyelet Piqué Twill Plain a) Structure and fiber content Structure [] Double jersey eyelet knit modification Double jersey piqué knit modification / S twist twill weave x plain weave Fiber content (%) * % polyester % polyester (face) % tactel (back) 9% cotton % spandex % polyester b) Characteristics Mean s.d. Mean s.d. Mean s.d. Mean s.d. Mass/unit area (g/m ) [] Black White Thickness (mm) [8] Black White Interstitial space (%) Black White Total UVR transmission ** [] Black White UPF ** [] Black White UPF rating ** [] Black White *Manufacturer specified **single layer, dry, non-extended - transmission/interstitial space not detected

8 a b c Eyelet Piqué Plain Fabric type d x x x Extension Black Color White Dry % % Wetness U V Figure Effect of fabric type, extension, color and wetness on mean UVR, UVA and UVB transmission (mean for each variable calculated over all other variables)

9 a 8 x% x% x% Mean UVR Eyelet Piqué Plain Mean UVA Eyelet Piqué Plain Mean UVB UVR, UVA and UVB transmission according to fabric type Eyelet Piqué Plain b c d Mean UVR Mean UVR x x x Mean x x x Mean x x x UVA UVB UVR, UVA and UVB transmission according to extension level Eyelet Piqué Plain Mean Eyelet Piqué Plain Mean Eyelet Piqué Plain UVA UVB UVR, UVA and UVB transmission according to fabric type Bla Dry Black White Mean UVR Eyelet Piqué Plain Mean UVA Eyelet Piqué Plain Mean UVB UVR, UVA and UVB transmission according to fabric type Eyelet Piqué Plain Figure Mean UV transmission (and s.d. bars) through single layers of selected fabric according to a) fabric type and extension level, b) extension level and color, c) fabric type and wetness, d) fabric type and color (mean calculated over all other factor levels)

10 8 UPF Mean Eyelet Piqué Plain Fabric type x% x% x% Figure Mean UPF (with s.d bars) of single layers of selected fabric according to fabric type and extension level 8 Layer Layer Layer Mean UVR Eyelet Piqué Plain Twill Mean UVA Eyelet Piqué Plain Twill Mean UVB Fabric type Eyelet Piqué Plain Twill Figure Effect of layering selected white fabrics on mean UVR, UVA and UVB transmission (with s.d. bars)

11 8 UPF Mean Eyelet Piqué Plain Twill Fabric type Layer Layer Layer Figure Effect of layering on mean UPF over all fabrics (mean) and selected (Eyelet, Piqué, Plain and Twill) fabric types (with s.d. bars)

12 References. Stanford, D G, Georgouras, K E and Pailthorpe, M, Sun Protection by a Summer-Weight Garment: The Effect of Washing and Wearing, Med. J. Aust. (8), - (99).. Wilson, C A and Parisi, A V, Protection from Solar Erythemal Ultraviolet Radiation Simulated Wear and Laboratory Testing, Text. Res. J. (), - ().. Gies, P H, Roy, C R, McLennan, A and Toomey, S, Clothing and Protection against Solar UVR, J. HEIA (), - (99).. Pailthorpe, M, Sun Protective Clothing, Text. Horiz. (), - (99).. Palacin, F, Textile Finish Protects against UV Radiation, Melliand Textilber , E-E (99).. Cox Crews, P and Kachman, S, Influences on UVR Transmission of Undyed Woven Fabrics, Text. Chem. Color. (), - (999).. Robson, J and Diffey, B L, Textiles and Sun Protection, Photodermatol. Photoimmunol. Photomed. - (99). 8. Gies, H.P., Roy, C.R., Elliott, G. and Zongli, W., Ultraviolet Radiation Protection Factors for Clothing, Health Phys. (), -9 (99). 9. Curiskis, J I, Postle, R and Norton, A H, "Fabric Engineering - Present Status and Future Potential." In Objective Evaluation of Apparel Fabrics, The Textile Machinery Society of Japan, Osaka, 98, 9-.. Moon, R. and Pailthorpe, M., Effect of Stretch and Wetting on the UPF of Elastane Fabrics, Australasian Text. (), 9,- (99).. Pailthorpe, M T and Curiskis, J I, "Sun Protection and Apparel Textiles." In Proceedings of the rd Asian Textile Conference Textile Research and Development in the Pacific Rim, The Federation of Asian Professional Textile Associations, The Hong Kong Institution of Textiles and Apparel, Hong Kong, 99,. Pailthorpe, M T, Textile and Sun Protection: The Current Situation, Australasian Text. (),,,9,-,, (99).. Gambichler, T, Hatch, K L, Avermaete, A, Altmeyer, P and Hoffman, K, Influence of Wetness on the Ultraviolet Protection Factor (UPF) of Textiles: In Vitro and in Vivo Measurements, Photodermatol. Photoimmunol. Photomed. 8 (), 9- ().. Zhou, Y and Crews, P C, Effect of OBAs and Repeated Launderings on UVR Transmission through Fabric, Text. Chem. Color. (), 9- (998).. Riva, A and Algaba, I, Ultraviolet Protection Provided by Woven Fabrics Made with Cellulose Fibres: Study of the Influence of Fibre Type and Structural Characteristics of the Fabric, J. Text. Inst. 9 (), 9- ().. Taylor, M A, "Technology of Textile Properties", Revised rd, Forbes Publications, London, 99.. Davis, S, Clothing as Protection from Ultraviolet Radiation: Which Fabric Is Most Effective, Int. J. Dermatol. (), -9 (99). 8. Böhringer, B, Schindling, G, Schön, U, Hanke, D, Hoffman, K, Altmeyer, P and Klotz, M L, UV Protection by Textiles, Melliand Textilber. -8 -, E-E8 (99). 9. Wang, S Q, Kopf, A W, Marx, J, Bogdan, A, Polsky, D and Bart, R S, Reduction of Ultraviolet Transmission through Cotton T-Shirt Fabrics with Low Ultraviolet Protection by Various Laundering Methods and Dyeing: Clinical Implications, J. Am. Acad. Dermatol. (), - ().. Reinert, G, Fuso, F, Hilfiker, R and Schmidt, E, UV-Protecting Properties of Textile Fabrics and Their Improvement, Text. Chem. Color. 9 (), - (99).. Bajaj, P, Kothari, V K and Gosh, S B, Review Article: Some Innovations in UV Protective Clothing, Indian J. Fibre Text. Res. (), -9 ().. Gorensek, M and Sluga, F, Modifying the UV Blocking Effect of Polyester Fabric, Text. Res. J. (), 9- ().. International Organization for Standardization, EN ISO : Textiles - Domestic Washing and Drying Procedures for Textile Testing, Geneva, International Organization for Standardization,.. British Standards Institution, BS EN ISO : Textiles - Domestic Washing and Drying Procedures for Textile Testing, London, British Standards Institution,.. British Standards Institution, BS EN 9:99; ISO 9:9. Textiles - Standard Atmospheres for Conditioning and Testing, London, British Standards Institution, 99.. Standards Australia/New Zealand Standard, AS/NZS 99:99, Sun Protective Clothing- Evaluation and Classification, Homebush NSW/Wellington, Standards Australia/Standards New Zealand, 99.. British Standards Institution, BS EN :998. Determination of Mass Per Unit Area Using Small Samples, London, British Standards Institution, 998.

13 8. British Standards Institution, BS : British Standard Methods for Determination of Thickness of Textile Materials, London, British Standards Institution, Rasbund, W, "ImageJ, Version.". National Institute of Health, U.S.A. Program, ().. SPSS Inc, Statistical Package for Social Sciences, Version.., Chicago, SPSS Inc, 99.. Harraway, J, "Introductory Statistical Methods and the Analysis of Variance", University of Otago, Dunedin, 99.. Fössel, M, Gassan, U, Köksel, B, Schuierer, M and Terrier, B, Practical Experience with Solartex Products in Finishing of Sun Protection Fabrics, Melliand Textilber. -8 -, E-E (99).. Srinivasan, M and Gatewood, B M, Relationship of Dye Characteristics to UV Protection Provided by Cotton Fabric, Text. Chem. Color. & Am. Dyestuff Reporter (), - ().. Kimlin, M G, Parisi, A V and Meldrum, L R, Effect of Stretch on the Ultraviolet Spectral Transmission of One Type of Commonly Used Clothing, Photodermatol. Photoimmunol. Photomed. (999).