Fire and Heat Protective Textiles

Fire and Heat Protective Textiles

The late twentieth century saw an unprecedented increase in emphasis on protection of the human form. Health and safety at work requires protective textiles for certain jobs and the threat of biological and chemical terrorist attacks is currently a topical issue. The range of hazards and the means of combating them continue to grow and become ever more complex. A consequence of this is the development and exploitation of new textile fibres, structures and clothing systems whose purpose is to provide improved protection, whilst maintaining comfort, efficiency and well being.

Protective materials are divided into impermeable, permeable, permeable absorptive and engineered permeable materials.

Impermeable materials prevent permeation of aerosols, liquids, and vapors. This applies to exterior contaminated air as well as to moisture and vapor produced by the user, creating uncomfortable environments when used for personal protective items. Butyl-rubber and polyethylene (PE) film are typical examples. Butyl-rubber and PE protective suits have better inherent to barrier protection, but do not ventilate. The Literatures document that wearing the gas-tight suits results in significant heat stress and seriously enhance the physiological heat load of the wearer.

Permeable materials are traditional textiles that allow vapours and liquids to pass through. These materials, when used in combination with suitable barrier compartments and finishes, have enhanced protective capabilities. Examples of treatment include altery the surface tension technology, wicking rate, and electrostatic surface treatments.

Permeable absorptive materials provide protection from vapour-phase contaminants by trapping vapours as they pass through the fabric. However, these materials do not protect as well against aerosols and liquids. Permeable absorptive materials are subdivided into activated carbon and zeolites, etc. Activated carbon, or activated charcoal, has been used historically for protection against chemical agents, but it has limited performance, especially in humid environments.

Engineered permeable materials have been specifically designed to restrict the penetration of toxic contaminants through the material but still allow water vapor transmission for evaporative cooling and personal comfort. Semi-permeable membranes, such as an expanded poly(tetrafluoroethylene) (PTFE) membrane is a typical example of engineered permeable technology.

Depending on individual applications, careful choice of suitable textiles and appropriate material is crucial for optimized protective properties of the garment.

Choice of fibre, weave and finish play an important role. Particularly in case of multi-layer apparel concepts and constructions,