Bringing down heat stress
Bringing down heat stress
Issue number 5090
At Interschutz, DuPont Personal Protection presented an improved concept for the development of heat-stress reducing, flame-resistant clothing. DuPont started investigating heat stress as a performance-reducing risk factor some years ago. Now, the DuPont™ SAM (Sweating Articulated Mannequin) and thermographic analysis have provided two evaluation methods, with which DuPont aims to bring down heat stress through flame and heat-protective clothing.
It is not just European Fire & Rescue Services that are beginning to pay more attention to heat stress ; recent statistics indicate that people in the USA are becoming increasingly aware of the risks of heat and physical stress. Physical stress was involved in a quarter of the 88,000 accidents in fire-brigade call-outs registered between 1995 and 2000 (statistics from the National Fire Protection Association) and it was also responsible for death in 46% of fatal accidents (according to the US Fire Administration). In addition to the physical condition of fire officers, increasing attention is being paid to the design of protective clothing. Instead of the old, heavy fire-proof suits, American fire officers are tending to use lighter clothing of the type that is worn in Europe.
SAM sweating for the fire brigade
In order to work on the minimisation of heat stress on a scientifically sound and verifiable basis, DuPont, in conjunction with the EMPA Swiss Research Institute for Material Sciences and Technology, is initiating a new test. Here a holistic approach is taken, integrating all the factors contributing to the occurrence of heat stress such as sweating, heat flow and the design of protective clothing. SAM, the mobile Sweating Articulated Mannequin, is a test dummy with sensors to measure moisture and temperature. Several factors such as the level of sweating, room temperature, relative humidity, running speed and wind speed can be set as required. The aim of this computer-assisted evaluation program is to discover how moisture is transported through all layers of clothing and how radiated heat affects the moist layers.
Thermographic analysis for tests under real conditions
With thermographic analysis, DuPont investigates protective clothing concepts under real conditions of use. It involves subjecting a test person (e.g. a fireman) to active physical stress and recording the heat distribution and transport of perspiration on body and clothing by means of a thermographic camera. In this way invaluable findings can be made regarding the clothing design, weak points can be localised and the effectiveness of complete protective equipment can be assessed. Thermographic analysis is particularly suitable for investigating multi-layered systems, aiming to minimise heat and perspiration and, finally, the risk of vapour burns.
Ideal balance between protection and comfort
The new analytical processes will be carried out in future by DuPont in addition to the flame tests on Thermo-Man®, in order to find the ideal balance between protection and wearability. Tests using SAM and thermographic analysis give us valuable additional information far exceeding that on the protective effect of workwear, explains Nicole Peschke from the DuPont Personal Protection Team. We are giving designers and end users the chance to find out more about the way their protective clothing concepts work and to make improvements in terms of heat stress on the basis of this knowledge.
In a world in which safety is treated with increasing importance, DuPont Personal Protection, specialist in personal protection from chemicals, heat, cuts and abrasion, constantly strives via its Research & Development Department to come up with new solutions for the comfort and safety of people at work. For more information on DuPont Personal Protection, please visit www.dpp-europe.com, contact Carolyn Buss at The McOnie Agency on tel 01483 237230 or email : Carolyn@mconieagency.com.