High-Intensity Thermal Testing of Protective Fabrics with a CO_2 Laser

摘要

A laboratory method has been developed to evaluate the thermal barrier performance of protective fabrics with a carbon dioxide (CO_2) laser. This experiment can apply high-intensity heat flux (up to 50 cal/cm~2s) to a fabric test specimen for a short duration (on the order of 100 ms) over a surface area of approximately 6 cm2. With these intensity and duration levels, results from the CO_2 laser test can be compared to those from ASTM F1959, which evaluates and rates the thermal protection performance of fabrics exposed to the controlled discharge of an electric arc. The CO_2 laser test uses the same analysis technique as that of ASTM F1959 to rate materials for thermal barrier performance. Data from both test methods are presented for several flame-resistant and protective fabrics. An advantage of the CO_2 laser test is the precision of thermal input to the test specimen. Differences in the contact between the test specimen and the calorimeter surface greatly affect the results of the CO_2 laser test. Developing a simple and repeatable technique to control this contact was achieved with two different configurations. Certain fabrics tended to deform when heated, which changed this contact and affected the test results. The closest correlation between the CO_2 laser test and arc rating test was achieved with an air gap spacer between the test specimen and calorimeter.