Foreword

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This document was prepared by Technical Committee ISO/TC 159, Ergonomics, Subcommittee SC 5, Ergonomics of the physical environment, in collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC 122, Ergonomics, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement).

This second edition cancels and replaces the first edition (ISO 14505-2:2006/Cor 1:2007), which has been technically revised.

The main change is as follows:

addition of an evaluation method for the contact areas (equivalent contact temperature).

A list of all parts in the ISO 14505 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A complete listing of these bodies can be found at www.iso.org/members.html.

Introduction

The interaction of convective, radiative and conductive heat exchange in a vehicle compartment is very complex. External thermal loads in combination with the internal heating and ventilation system of the vehicle create a local climate that can vary considerably in space and time. Asymmetric thermal conditions arise, and these are often the main cause of complaints of thermal discomfort. In vehicles without or with poor heating, ventilating and air-conditioning system (HVAC-system), thermal stress is determined largely by the impact of the ambient climatic conditions on the vehicle compartment.

Subjective evaluation is integrative, as the individual combines into one reaction the combined effect of several thermal stimuli. However, it is not sufficiently detailed or accurate for repeated use. Technical measurements provide detailed and accurate information but must be integrated in order to predict the thermal effects on humans. Since several climatic factors play a role for the final heat exchange of a person, these factors must be integrated to a measure, representing their relative importance.

This document includes the equivalent temperature models t_eq for the assessment of the thermal conditions. For special consideration of the seat, the equivalent contact temperature t_eq,cont can be applied for body compartments in contact to surfaces. Methods for the calculation of t_eq using thermal factors are described in ISO 14505-4. The methodology described in this document can also be used in specific performance standards for testing of HVAC-systems for vehicles and similar confined spaces.

1 Scope

This document specifies requirements and recommendations for the assessment of the thermal conditions inside a vehicle compartment. It can also be applied to other confined spaces with asymmetric climatic conditions.

It applies to the assessment of thermal conditions, when deviations from thermal neutrality are relatively small.

2 Normative references

3 Terms and definitions

4 Assessment principles

4.1 General

4.2 General description of equivalent temperature

4.3 General determination principle of equivalent temperature

5 Specific equivalent temperatures

5.1 General

5.2 Whole body equivalent temperature

5.3 Segmental equivalent temperature

5.4 Directional equivalent temperature

5.5 Omnidirectional equivalent temperature

6 Measuring instruments

7 Assessment

7.1 General

7.2 Determination of whole body equivalent temperature

7.3 Determination of local equivalent temperature

8 Equivalent contact temperature

8.1 General

8.2 Calculation methodology

Bibliography