Thermal stress assessment in severe cold work environments: redesign of the IREQ index calculator according to age and gender

This paper presents an updated version of the required thermal insulation index (IREQ) calculator based on ISO 11079:2007. The structural change required the revision of parameters, the use of Java and Visual Studio for code changes, and a testing phase. The redesigned version indirectly calculates metabolic rate, using operator information (i.e., age, gender, height, weight, mean heart rate, and heart rate at rest) rather than requiring this value input for IREQ calculation. Thus, the "analysis" approach of the UNI EN ISO 8996:2021 standard for calculating the metabolic rate value is more precise than its random determination. Furthermore, the new calculator simplifies entering the insulation and air permeability values of clothing by introducing a list of possibilities according to UNI EN ISO 9920:2009 and UNI EN ISO 9237:1997 standards. The IREQ software redesign aims to simplify the input of complex values and make a risk assessment in cold environments more accurate.