Study On The Effect Of Wearing Methods On Clothing Thermal Resistance

The clothing hind the heat transfer between the human body and the environment called the clothing insulation performance,and the traditional characterization is thermal resistance(clo).In the definition of clo value,clothing is considered as a single state of wearing and the thermal resistance of the clothing is unique and fixed.In fact,when the state of wearing changes,the coverage area of the clothing on the human body and clothing openings will change at the same time,which will cause the performance changing of clothing insulation.Obviously,different wearing ways of clothing will have different thermal resistance values.The relations between the elements of the wearing ways and the clothing thermal resistance will be studied to inquiry the"variability" of thermal resistance to complement the concept of clothing thermal resistance.Three main thermal resistance impact factors included in the change of wearing methods were summed up based on the theory of clothing insulation performance:the area coverage of clothing on human body,the clothing openings and the fabric raphe on partial position of human body.The appropriate characterization indicators and measurement methods were determined respectively:the area of coverage(BSAC)was calculated by 3D body scanning data;the ventilation index(VI)was calculated by the air exchange rate and the volume of the air layer under clothing;and the "partial thickness index" was defined by measuring the partial thickness of clothing combined with the cold feel of the different parts of the body.An adjustable experimental garment was designed combined the influenced factors of thermal resistance included in the above wearing methods,and from the point of clothing to be"wearable" and to meet the requirements of ergonomics perspective.The design and optimization process of the lab coat can provide the reference in development of functional apparel products,especially changes in ways of wearing design methods.Firstly,it was determined that the experimental wear fabrics need to include the two variable thickness and permeability by the preliminary experiments.Then the style and structure of lab coat were designed.The major design optimization details including:① The two typical placket zipper pulling positions were determined as the anterior cervical points down 11cm and 36cm.②The best fixed position of the body and clothing after the sleeves opened was determined through action research method.③The most suitable height of the sleeves rolling up was elbow down 7.167cm.The experimental results of the clothing insulation performance under the changes of wearing ways were analyzed from two aspect:single-factor and multi-factor interactions affect.Correlation analysis of single factor with clothing thermal resistance showed that:①BSAC and garment thermal resistance showed a significant positive correlation,VI and clothing thermal insulation showed a significant negative correlation.And there was no significant correlation between PTI and garment thermal resistance;②In the effect of clothing thermal resistance,BSAC and VI promoted each other,an d the PTI would weaken the regulation function of BSAC and VI;③1n the process of wearing way changed,the regulation function of BSAC,VI and PTI were:BSAC>VI>PTI.The thermal resistance measurement results of different wearing methods showed that the rate of change of the effective thermal resistance of clothing was up to 44%.This fully showed that the values of the thermal resistance of a garment were the changeable range.Simulate calculate of the clothing Rated temperature forecast also showed that:The rated temperature range of this set of clothing was 11.03～16.06 ℃.And the calculated nominal temperature value was 11.896 ℃.Compared to the single temperature,the temperature range were more practical.In summary,the study on the wearing methods changes impacting the clothing insulation showed that:The wearing methods influenced the clothing insulation performance through the Body Surface Area Coverage,Ventilation Index and Partial Thickness Index to make the thermal resistant of one garment "variability".This is an effective complement to the traditional thermal resistance theory which a piece of clothing has only one fixed thermal resistance.