nonbreathable

Nonbreathable is an adjective used to describe materials, fabrics, or coverings that restrict or prevent the passage of air or water vapor. In technical contexts, nonbreathable implies very low moisture vapor transmission rate (MVTR) and often high impermeability to liquid water. By contrast, breathable materials allow some air or moisture to pass through, reducing condensation and heat buildup.

In apparel and textiles, nonbreathable fabrics or coatings include rubber, vinyl, polyurethane, or laminated films. They may be used for rainwear, chemical protection garments, or industrial upholstery. While they provide water resistance or waterproofing, they tend to trap perspiration, leading to moisture buildup, increased heat, and potential discomfort or skin irritation with prolonged wear. Performance is often described in terms of MVTR and hydrostatic head (water pressure resistance) ratings.

In construction and industry, nonbreathable barriers can function as vapor barriers or waterproof membranes. They protect structures or processes from liquid ingress but can also trap moisture within walls or equipment if not properly vented or drained. This moisture trapping can contribute to mold growth, material degradation, or corrosion when ventilation and drainage are inadequate. Designers balance waterproofing with appropriate ventilation or the use of more sophisticated materials that block liquid water while allowing vapor to pass.

Overall, nonbreathable fabrics and barriers emphasize liquid impermeability at the potential cost of reduced comfort or moisture management in wearable or built environments.