ISO 18640-1:2018

Overview - ISO 18640-1:2018 (Protective clothing for firefighters, sweating torso)

ISO 18640-1:2018 specifies a laboratory test method to evaluate the thermo-physiological impact of fabrics and clothing assemblies used in firefighter protective clothing. Using a controlled sweating torso apparatus and a climatic chamber, the standard measures coupled heat and moisture transfer during a series of simulated activity phases. The method characterizes essential fabric/ensemble properties-dry thermal insulation, cooling properties during typical metabolic activity, moisture management (dry and wet heat transfer) and drying behaviour-to support material selection and garment optimization.

Key topics and technical requirements

• Apparatus and setup
  • Sweating torso (heated cylinder with temperature control, thermal guard sections, simulated perspiration and wicking layer)
  • Climatic chamber, fan system, sweat water supply, control computer and data acquisition
• Measured properties
  • Dry thermal insulation (Rct)
  • Cooling under simulated metabolic loads
  • Coupled dry and wet heat transfer and drying behaviour
• Specimens and configurations
  • Default testing on fabric samples representing a garment or ensemble
  • Optional testing on more complex configurations (underwear, air layers, certain design features) and readymade garments
  • Note: added air or underwear layers change insulation; direct numeric comparison between configurations is not always possible (Empa validation referenced)
• Procedure and quality control
  • Defined conditioning, dressing of torso, wind speed and ambient control
  • Data acquisition, calculated outputs and reporting requirements
  • Calibration, maintenance and validation procedures (annexes include calibration guidance and example data processing)
• Limitations
  • Intended to describe thermo-physiological impact under laboratory conditions - not a direct measure of heat-stress risk in real fire incidents. Results can be used as input to broader risk assessments.

Applications and who uses it

• Firefighter PPE designers and manufacturers use ISO 18640-1 to:
  • Compare fabric assemblies and optimize material selection
  • Validate design choices regarding moisture management and thermal comfort
• Test laboratories and research institutes use the standard to run reproducible sweating-torso evaluations
• Occupational safety specialists and procurement teams use results as part of risk assessment and specification development for firefighter protective ensembles
• Standards committees and certification bodies refer to these measurements when developing performance criteria for firefighter garments

Related standards

• ISO 18640 series - Part 1 pairs with ISO 18640-2 and other parts of the ISO 18640 family for a comprehensive thermo-physiological assessment of firefighter protective clothing and ensembles.

Keywords: ISO 18640-1, protective clothing for firefighters, sweating torso, heat and moisture transfer, thermo-physiological assessment, firefighter PPE, fabric assemblies.