Overview
ISO 14505-2:2026 is an international standard developed by ISO, focusing on ergonomics of the thermal environment with a specific emphasis on evaluating thermal environments in vehicles. This standard outlines requirements and recommendations for assessing the thermal conditions inside a vehicle compartment, but it is also applicable to other confined spaces characterized by asymmetric climatic conditions. The guidance is particularly relevant when deviations from thermal neutrality are relatively small.
A major part of the standard is the determination of equivalent temperature, a scientifically-based measure that integrates the effects of convection, radiation, and, where relevant, conduction and evaporation, to describe the thermal stress experienced by occupants.
Key Topics
- Equivalent Temperature (teq): This is a unified metric that integrates convective and radiative effects, representing the temperature of a homogeneous environment where a person would experience the same heat exchange as in the measured space.
- Whole Body Equivalent Temperature: Assesses the net heat exchange affecting the entire body, typically measured using thermal manikins with multiple zones that simulate human thermoregulation.
- Segmental Equivalent Temperature: Focuses on specific body parts or segments, such as the hands, head, or thighs, providing localized thermal assessment.
- Directional and Omnidirectional Equivalent Temperature: Employs specialized sensors to capture both targeted and averaged heat exchange over a defined area or direction, useful for detailed climate mapping inside compartments.
- Equivalent Contact Temperature: Introduced in this edition, this concept addresses the impact of direct body contact with surfaces (like seats), accounting for heat conduction and local moisture effects.
- Measurement and Calibration: The standard includes comprehensive recommendations for selecting and calibrating measurement instruments, such as thermal manikins and various sensors, to ensure consistent and valid results.
Applications
ISO 14505-2:2026 is a critical resource for:
- Vehicle manufacturers: Ensuring occupant comfort and optimizing HVAC performance during vehicle development and testing.
- Automotive HVAC engineers: Evaluating and comparing different heating, ventilation, and air conditioning systems using a standardized thermal measurement methodology.
- Ergonomics and Human Factors specialists: Assessing human thermal comfort and local discomfort in vehicle cabins and designing environments for enhanced wellbeing and safety.
- Testing Laboratories and Certification Bodies: Providing a benchmark method and terminology for validating climate conditions within vehicles or similar confined spaces.
- Researchers and Designers: Studying the effect of non-uniform climates and direct surface contact on human thermal sensation, especially in complex environments like modern vehicles.
Related Standards
To understand and apply ISO 14505-2:2026 effectively, it is recommended to consult these related standards:
- ISO 13731: Ergonomics of the thermal environment - Vocabulary and symbols
- ISO 14505-1: Ergonomics of the thermal environment - Evaluation of thermal environments in vehicles - Part 1: Principles and methods for assessment of thermal stress
- ISO 14505-3: Ergonomics of the thermal environment - Evaluation of thermal environments in vehicles - Part 3: Evaluation of thermal comfort using human subjects
- ISO 14505-4: Guidance for use of equivalent temperature models with thermal manikins
- SAE J2234: Standard practice for measuring and reporting directional heat exchange in vehicle environments
Practical Value
By adopting ISO 14505-2:2026, organizations can:
- Standardize the evaluation of thermal comfort, enhancing occupant satisfaction and product quality.
- Objectively compare different HVAC technologies or vehicle designs.
- Meet regulatory and customer requirements for indoor climate control in transportation.
- Gain reliable, repeatable data for product development, quality assurance, and research.
- Ensure global compatibility and consistency in thermal environment assessment for vehicles and other confined spaces.
Keywords: ISO 14505-2:2026, vehicle thermal environment, equivalent temperature, thermal comfort assessment, automotive HVAC, ergonomic standards, thermal manikins, confined space climate, thermal environment evaluation.