Overview
ISO 11092:2014 - Textiles - Physiological effects - Measurement of thermal and water‑vapour resistance under steady‑state conditions (sweating guarded‑hotplate test) specifies a laboratory method to quantify how textile materials resist heat and evaporative moisture transfer. Known as the sweating guarded‑hotplate (skin model), the standard measures thermal resistance (Rct) and water‑vapour resistance (Ret) for fabrics, films, coatings, foams, leather and multilayer assemblies used in clothing, quilts, sleeping bags, upholstery and similar products. The standard defines steady‑state test conditions and apparatus limits (for minimum equipment specs, e.g. ~2 m2·K/W thermal resistance and ~700 m2·Pa/W water‑vapour resistance).
Key topics and technical requirements
- Principle: A heated plate simulates skin; heat flux and evaporation through a specimen are measured under steady‑state air and humidity conditions to determine Rct and Ret.
- Measured quantities:
- Thermal resistance (Rct) - m2·K/W
- Water‑vapour resistance (Ret) - m2·Pa/W
- Water‑vapour permeability index (imt) - dimensionless ratio relating Rct and Ret
- Measuring unit and controls:
- Porous metal plate (~3 mm thick) fixed to a heated block; minimum measuring area ~0.04 m2 (e.g. 200 mm square).
- Plate emissivity > 0.35 (8–14 µm at 20 °C).
- Temperature control of the measuring unit to ±0.1 K; heating power measurable to ±2 %.
- Water dosing to the porous plate with preheated feed for evaporation; membrane prevents liquid water contacting specimen.
- Thermal guard: High‑conductivity guard to reduce lateral heat losses; minimum width ~15 mm and gap to plate ≤1.5 mm.
- Test procedure & reporting: Includes apparatus calibration, specimen mounting (with annexes covering uneven or loose‑filled materials), measurement steps for Rct and Ret, and precision statements on repeatability and reproducibility.
Applications
- Material selection and product development for apparel, outdoor gear, bedding and upholstery where heat and moisture transfer affect comfort.
- Comparative performance testing and quality control in textile R&D and testing laboratories.
- Research into fabric comfort, breathable membranes and multilayer assemblies.
- Input for comfort modelling and performance labeling (note: ISO 11092 does not prescribe specific comfort thresholds).
Who uses this standard
- Textile and garment manufacturers, outdoor and sleep product designers
- Independent test laboratories and certification bodies
- R&D teams studying thermal/moisture transport in textiles
- Standards committees and regulatory labs engaged in comfort testing
Related standards and notes
- ISO 11092:2014 is the second edition, revising ISO 11092:1993 (incorporating Amendment 1:2012). It is part of a broader suite of standards addressing textile physiological effects and comfort testing.
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