ISO/TR 23672:2026 PDF

Overview

ISO/TR 23672:2026, Ergonomics of the thermal environment: Adaptive methods for achieving thermal comfort, is an ISO Technical Report focused on defining adaptive thermal comfort and its mechanisms. The standard presents current approaches for predicting adaptive thermal comfort in indoor built environments, with emphasis on seasonal adaptation processes. It is applicable to the design of new indoor spaces or the assessment of existing ones, targeting healthy individuals in environments where thermal comfort is desirable but may experience moderate deviations.

Adaptive methods help to improve occupant comfort by accounting for how people naturally adjust to their environment over time. This document is vital for architects, building engineers, HVAC designers, facility managers, and ergonomics professionals aiming to optimize thermal comfort and energy performance in buildings.

Key Topics

• Adaptive Thermal Comfort Definition and Mechanisms: The standard addresses physiological, behavioural, and psychological adaptation processes that influence human thermal comfort. These include changes in metabolic response, clothing adjustments, and psychological perception of the environment.

• Thermal Comfort Models:

  • Regression-Based Adaptive Models: These use statistical relationships between outdoor air temperatures and indoor neutral operative temperatures derived from field studies.
  • Adaptive PMV (aPMV) Model: Expands on the classic Predicted Mean Vote (PMV) index by integrating coefficients that reflect occupants’ adaptive feedback loops.
  • Adaptive Thermal Heat Balance (ATHB) Model: This comprehensive approach combines traditional heat balance calculations with explicit mechanisms for all three adaptation types.

• Assessment Parameters: The report covers essential variables such as mean outdoor air temperature, running mean outdoor temperature, clothing insulation levels, metabolic rates, and thermal sensation votes.

• Implementation in Standards: Discussion of how these adaptive models are applied in both national and international building standards, such as ISO 17772-1 and Chinese National Standard GB/T 50785-2012.

Applications

ISO/TR 23672:2026 delivers practical value in the following contexts:

• Indoor Environmental Quality Design: Use adaptive models to guide the design of heating, ventilation, and air conditioning (HVAC) systems that optimize comfort while enhancing energy efficiency in both new and retrofitted buildings.

• Occupant-Centric Assessments: Evaluate and improve thermal comfort by accounting for occupants’ actual adaptation behaviors, habits, and local climate influences in offices, schools, healthcare facilities, and residential buildings.

• Seasonal and Climate-Zone Adaptation: Recognize and accommodate differences in thermal comfort expectations and adaptation processes across various seasons and geographical locations.

• Compliance and Performance Evaluation: Support compliance with building performance and indoor environmental quality standards by using adaptive thermal comfort models that reflect real occupant experiences.

• Inclusion of Adaptive Feedback: Aligns building design and operation with evidence-based human responses to their environment, supporting both productivity and well-being.

Related Standards

Many other ISO standards are referenced and complement the application of ISO/TR 23672:2026, including:

• ISO 7726: Instruments for measuring physical quantities in the thermal environment.
• ISO 7730: Analytical determination and interpretation of thermal comfort using the PMV and PPD indices.
• ISO 8996: Determination of metabolic rate.
• ISO 9920: Estimation of thermal insulation and water vapor resistance of clothing.
• ISO 13731: Vocabulary and symbols for the thermal environment.
• ISO 17772-1/2: Energy performance of buildings-Indoor environmental input parameters and performance assessment.

These standards help form a cohesive framework for designing, assessing, and improving thermal environments in buildings according to global best practices.

By applying the guidelines in ISO/TR 23672:2026, stakeholders can deliver indoor spaces that respond dynamically to user needs, advances in ergonomics, and regional climatic variations, ensuring both comfort and operational efficiency.