GB/T 40261.2-2021 in English

Analysis of the core content of the standard

This standard establishes a systematic method for evaluating the thermal environment inside a vehicle through subject experiments, focusing on solving the problem of quantifying thermal comfort in dynamic and complex environments. Its technical framework includes three major evaluation dimensions:

Evaluation dimensions	Measurement indicators	Implementation points
Subjective method	Thermal sensation/discomfort/stickiness score	Use a 7-point scale to collect data every 10 minutes
Objective method	Skin temperature/heart rate changes	Must comply with ISO9886 standards
Behavioral method	Posture adjustment/seat selection	Need to exclude non-temperature interference factors

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Key technical implementation points

1. Experimental design specifications

The standard requires at least 8 representative subjects to participate in the experiment, and a Latin square design is used to eliminate the order effect. The test duration must be ≥30 minutes and is carried out under the stable operation of the HVAC system.

2. Application of subjective scales

Three types of standardized scales are used as the core:

• Thermal sensation scale (7 levels: -3 cold ~ +3 hot)
• Discomfort scale (4 levels: 0 no discomfort ~ 3 extreme discomfort)
• Thermal expectation scale (7 levels: -3 cooler ~ +3 hotter)

Appendix B provides a standardized questionnaire template, and it is recommended to use a single-page design to reduce interference.

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Industry application value

Standard Evolution Analysis

Compared with the 2006 version of the ISO standard, GB/T40261.2-2021 has the following major enhancements:

• Added local assessment requirements for seats/windows, etc.
• Refines the control of extreme weather test conditions
• Supplements data statistical processing specifications

Reflects my country's technological progress in the field of dynamic thermal environment assessment.