2007, Piran, Slovenia

Thermal comfort
DEVELOPMENT OF AN INTERNATIONAL STANDARD FOR THE
ASSESSEMENT OF INTEGRATED ENVIRONMENTS.
Simon Hodder, Ken Parsons
Department of Human Sciences, Loughborough University, Loughborough, UK
Contact person: k.c.parsons@lboro.ac.uk
INTRODUCTION
Practising ergonomists are often required to evaluate a total working environment (Thermal,
Lighting, Noise, Vibration and Air Quality), but there are few formalised systems that allow
the non specialist to achieve this completely. The use of monitoring equipment can restrict the
ergonomist from determining if there are environmental issues within the workplace. A new
International Standard (ISO 28802) is currently being developed to bring together evaluation
methods for the general ergonomist. This paper describes the principles and the structure of
the Standard which is currently out for International vote. The aim of the Standard is to
provide an environmental survey method for assessing the comfort and well being of indoor
and outdoor environments. It is not restricted to any particular environment, but provides the
general principles that allow assessment and evaluation.
METHODS
The Standard utilises a number of methods to assess an integrated environment; Objective,
Subjective and Behavioural. It will provide advice on how to set up the environmental survey.
It will include where, when and what to measure as well as general advice on how to conduct
the survey. Sampling methods will be presented for objective and subjective measurements.
Objective methods: Objective methods quantify the physical or mental condition of a person
by the use of instrumentation or measures of an output such as performance measures. The
principle of the method is that the measure can be interpreted in terms of the human condition
of interest (e.g. comfort). An example would be the measurement of mean skin temperature of
the body that would vary with the thermoregulatory response to heat and cold (providing a
rationale for the method) that has been shown to correlate with subjective responses. Another
example would be skin wetness. Disadvantages of objective methods would be that they
might interfere with what they are attempting to measure, the correlation between the measure
and comfort is not perfect, and that comfort is a psychological phenomenon, a condition of
mind. An advantage of objective measures is that they are often independent of, and can be
used to complement, the results of other methods such as subjective measures.
Subjective methods: Subjective methods quantify the responses of people to an environment
using subjective scales. Such scales are based upon psychological continua (or constructs)
that are relevant to the psychological phenomenon of interest. It is important to know the
properties of the scales to correctly interpret the results. Scales of sensation (e.g. hot or cold),
preference, comfort, annoyance smell and stickiness are often used in comfort assessment.
Advantages of subjective methods are that they are simple to administer and are directly
related to the psychological phenomenon. ISO 10551 provides guidance on the construction
of subjective scales. Five types of scales are identified: perceptual (How do you feel now? e.g.
hot); affective (How do you find it? e.g. comfortable); preference (How would you prefer to
be? e.g. cooler); acceptance (acceptable/unacceptable); tolerance (Is the environment
tolerable?). From these dimensions, subjective scales can be developed.
Behavioural methods: Behavioural methods quantify or represent human behaviour in
response to an environment. The particular aspect of human behaviour observed is related to
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