Modelling the Effectiveness of Techniques for Reducing Heat Strain in Royal Navy Nuclear, Biological and Chemical Cleansing Stations' Teams

Abstract

High temperatures, combined with wearing nuclear biological chemical (NBC) individual protective equipment (IPE), produce significant heat strain in personnel working in ships' NBC cleansing stations (CS) and limit the ability of ships to operate in a contaminated environment. This report reviews the potential solutions to this problem and concludes that only a method of actively cooling personnel will reduce heat strain and increase the number of people that can be processed through ships' NBC CS. Amongst the wide range of cooling equipment that might offer a benefit, only hand immersion in cold water and ice-vests are practically useful for use in NBC CS. To assess how effective these techniques are likely to be INM has modelled the thermal effects under environmental conditions expected in the CS when operating in a hot climate. The model predicted that hand immersion in cold water (10 degrees C) would be the most effective cooling method, providing that personnel were able to take regular rest periods to immerse the hands. If it is preferred that personnel in the CS be able to work continuously, then ice-vests would be effective. The safe total work time that can be achieved in a three hour period without a cooling intervention is approximately 72 minutes, regular rest periods must be taken throughout the three hour work period, to total of 108 minutes. Safe work times can be increased to 99 minutes by using an ice-vest and 117 minutes by using hand immersion in 10 degrees C water, with required rest times reduced accordingly, thereby increasing capacity of CS teams to decontaminate personnel.