This paper reports two experimental studies wherein the combustion process of flame resistant (FR) thermal protective textiles is characterized in terms of thermal decomposition and heat release parameters before and after contamination and in terms of heat release parameters after contamination and decontamination. Aramid and FR cotton/nylon decomposed at higher and aramid/FR viscose at lower temperature in the presence of oil. Oil interferes with thermally induced interactions between aramid and FR viscose, altering the thermal decomposition rates and formation of char, and thereby increasing the effectiveness of the flame retardant present in the viscose. It is apparent that oily contaminants present in FR fabrics affect the initiation of the thermal degradation and formation of char. All contaminated FR fabrics showed significantly higher peak heat release rate (PHRR), total heat release (THR) and effective heat of combustion (EHC) compared to uncontaminated ones. Oily specimens laundered with no detergent or prewash product had higher PHRR, THR and EHC compared to other treatments regardless of the fabric type or number of contamination/decontamination cycles. Heat release increased with increased number of contamination/decontamination cycles for most laundry treatments for all FR fabrics. FR cotton/nylon had the highest and aramid had the lowest PHRR and THR whether specimens were uncontaminated, contaminated or decontaminated. In this study heat release from FR fabrics increased with increased oily contamination.

This paper reports an experimental study wherein the quantity and distribution of oily contaminants present in flame-resistant fabrics (FR) after contamination and decontamination was determined using radiotracer analysis and scanning electron microscopy. The experimental variables were fabric type, laundry treatment, and number of contamination/decontamination cycles. Laundry treatments involving a pre-wash product were the most effective in removing oil from all FR fabrics regardless of the number of contamination/ decontamination cycles. Accumulation of oily contaminants was noted after five contamination/ decontamination cycles regardless of the fabric type or laundry treatment. FR cotton/nylon retained the most residual oil for all laundry treatments. No oil remained in the interior of the aramid, viscose, and nylon fibers, but rather remained on the surface so that it was removed easily during decontamination. A significant quantity of oil was located in the interior of the cotton fibers, making it difficult to remove during decontamination.

This paper reports an experimental study wherein flame resistance and limiting oxygen index of protective fabrics were determined before and after contamination with oil and after decontamination. Experimental variables were presence of contamination, laundry treatment, number of contamination/decontamination cycles, and fabric type. Although laundering with pre‐wash products alone was the most effective in removing oil, some product residues may have contributed to the increased flammability of some fabrics. Thus, use of that product was truly effective only if combined with detergent. For two fabrics higher flammability was noted after five contamination/decontamination cycles than after one. Of the three fabrics studied, aramid specimens retained the least oil, and although they had the highest flammability both before and after contamination, it increased the least with contamination. The FR cotton/nylon fabric retained the most oil after decontamination, but had better flame resistance than aramid. Much of the oil remained in the interior of cotton fibres making it difficult to remove but also less accessible for vaporization and combustion. For the aramid/FR viscose, energy from combustion of residual oil activated the FR additive, thereby reducing apparent fabric flammability, but this FR transference effect occurred only up to an optimum quantity of oil. Copyright © 2010 John Wiley & Sons, Ltd.