This study explored the application of shape memory alloy (SMA) springs in a multilayer protective fabric assembly for intelligent insulation that responded to thermal environment changes. Once the SMA spring was actuated, clothing layers were separated, creating an adjustable air gap between the adjacent fabric layers. The impacts of six different SMA arrangement modes and two different spring sizes on thermal protection against either a radiant heat exposure (12 kW/m²) or a hot surface exposure (400 °C) were investigated. The findings showed that the incorporation of SMA springs into the fabric assembly improved the thermal protection, but the extent to which the springs provided thermal protection was dependent on the arrangement mode and spring size. The effectiveness of reinforcing the protective performance using SMA springs depended on the ability of clothing layers to expand an air layer. The regression models were established to quantitatively assess the relationship between the air gap formed by SMA spring and the thermal protective performance of clothing. This study demonstrated the potential of SMA spring as a suitable material for the development of intelligent garments to provide additional thermal protection and thus reduce the number of clothing layers for transitional thermal protective clothing.

The development of environmental responsive and self-adjustable structure is very important for improving protective performance of protective clothing, and thus decreases burn injury chance of firefighters and emergency rescuers. Shape memory material (SMM) can be incorporated into clothing system to provide necessary thermal protection when threaten occurs. It will produce stable air gap when SMM is actuated, therefore reduces heat transfer to human body. Under normal conditions, the SMM is flat that doesn’t affect wearer’s motion ability and wearing appearance. This article overviewed and summarized the international state-of-the-art research status on the application of SMM in both thermal and cold protective clothing. The key issues in this area were discussed. Based on the above analysis, the specific direction for the application of SMM in protective clothing in the future was highlighted in terms of air gap size, heat exposure, protective clothing factors, quantity and distribution of SMM, etc. And the development trend in protective clothing incorporated with SMM was proposed from the perspective of human-clothing-environment system.

To improve thermal protection of protective clothing, temperature-responsive protective fabrics incorporated with shape memory alloy (SMA) springs varying on four different deformation heights and five types arrangement modes were designed. The thermal protection was investigated under radiant heat exposure of 0.39 cal/cm² s. The results indicated that the air gap between fabric layers produced by SMA springs effectively improved protective performance. The thermal protection of fabrics with different SAM arrangement modes and sizes showed different trends, and the interaction effects of arrangement mode and size were analyzed. Moreover, the optimized arrangement and size of SMA springs were suggested. The regression models were established to assess the relationship between the air gap and thermal protection. This study demonstrated that the combination of flame-resistant fabric with SMA was feasible to develop temperature-responsive protective clothing because it could improve thermal insulating property by producing intelligent air gaps that responded to environment change.

Except for providing thermal protection, thermal protective clothing (TPC) may also impose thermal hazards on human skin due to the discharge of energy storage. The dual thermal protective/thermal hazardous performance of TPC is rather complicated when TPC gets wet from internal and external sources and especially when it is exposed to conditions of pressurized hot steam. In this study, several indices were used to quantitatively investigate the influences of moisture location, moisture content within TPC, and their combined effect on the energy storage caused dual performance of TPC under exposure to steam. Results showed that both the increasing of external and internal moisture could decrease heat absorption of the skin and increase burn injury time under steam exposure through heat storage, but the positive effect of the external moisture amount was more obvious. The external moisture amount had no significant effect on heat discharge from TPC to the skin, whereas the internal moisture amount increased heat discharge. Empirical models were successfully established to predict the energy absorption of human skin and the burn injury time. Research outcomes of this study will contribute to thoroughly understanding the impact of moisture on dual performance under steam exposure and provide new insights into the development of functional textile materials.