UV protective clothing–A new evaluation approach

Purpose

To develop a comprehensive index that can quantify the capability of sun-protective clothing and take into account both the BSA coverage achieved by the design of the garment and the UPF of the fabric itself.

Approach

A mannequin model was fixed to an optical bench and marked with horizontal lines at 1cm intervals. An algorithm (the Garment Protector Factor; GPF) was developed and BSA coverage was determined based on the number of lines visible on a clothed versus an unclothed mannequin.

The GPF can be determined using Equation 1, by including two linear variables for the UPF and relative BSA that is covered, and it can define if a protective clothing can meet or will exceed minimum international standards for sun-protective clothing.

Equation 1    

Where P is the number of surface contours protected/covered by a particular garment when the mannequin model is clothed, U is the maximum number of body contours defined in the BSA quotient for clothing of the relevant size and the number of body contours that must be covered by a garment to meet the minimum BSA standard is µ. The algorithm takes into account the age and size of the person and upper, lower or full body garment elements as well.

Three-year-old mannequin marked with horizontal lines at 1cm intervals. Practical clothing limits are marked at the neck and ankle with the hip-line separating the upper and lower body. The maximum possible sleeve length corresponds with the wrist. Contours used for minimum standard lengths are highlighted in green (upper body) and yellow (lower body).

Results

The GPF was designed to be consistent with the current Australian, New Zealand, European and US standards that evaluate and classify sun-protective clothing. According to the revised Australiana and New Zealand standard, the upper-body, lower-body and all-in-one garments are already categorised to either ‘meet’ the standard (minimum UPF 15), provide ‘good’ protection (minimum UPF 30) or ‘excellent’ fabric protection (UPF 50 or 50+). The new presented method combined BSA and UPF in a single equation for incorporation into future revisions of this and other standards, so that manufacturers of garments striving to incorporate higher UPF-rated textiles and designing garments covering more than the minimum specified BSA can achieve a higher categorical score.

In the results of this research, three categorical scores were adopted to be consistent with AS/NZS 4399:2017. These three categories are: ‘minimum standard’ (0 ≤ GPF < 3); ‘good protection’ (3 ≤ GPF < 6); and ‘excellent protection’ (GPF ≥ 6) for garments that just meet the minimum BSA requirement but have progressively higher UPF ratings. The categories introduced here can also reward sun-protective garment designers by the application of Equation 1, whereby the gradient of GPF vs UPF increases as the protected BSA increases.

Impact

This designed sun-protective clothing index (GPF) could potentially be implemented universally in industry standards and could form a new rating system that has the potential to encourage fashion designers and manufacturers to design better sun-protective clothing that can be assessed (quantitatively) by taking into account both the UPF and the total protected BSA. This labelling system can also provide more information to the costumers about the benefits of garments that they are buying as to what extent they can protect the skin surface physically and practically.