2007, Piran, Slovenia

Environmental Ergonomics XII
Igor B. Mekjavic, Stelios N. Kounalakis & Nigel A.S. Taylor (Eds.), © BIOMED, Ljubljana 2007
SENSITIVITY OF RESPONSES USING PERCEPTION SCALES THAT
ASSESS TORSO AND OVERALL THERMAL PERCEPTIONS IN
WARM STABLE AND DYNAMIC ASYMMETRIC ENVIRONMENTS
Mark Newton, Tara Reilly, Sarah Davey, Michael Tipton
University of Portsmouth, Portsmouth, UK
Contact person: mnewton@wlgore.com
INTRODUCTION
An assessment of thermal comfort has been measured in human experimentation using a wide
range of scales, the most popular being a Likert type scale with 4-7 points for characterizing
thermal comfort, temperature sensitivity, and skin wettedness. Many researchers have
investigated the perceived effect of microclimate temperature and relative humidity (RH) as
measured by these scales (Fanger, 1970, Gagge 1986, Havenith, 2002). More recently visual
analog scales (VAS) have become popular. Comfort studies have demonstrated the superior
resolution of this type of scale for individual subject partial body assessments, and comfort in
dynamic environments (Zhang, 2003).
The present study was designed to utilize a VAS scale to determine subject responses to static
and dynamic warm thermal asymmetric (non-uniform) environments. These environments
were created around the torso using an air perfused vest (APV) connected to a purpose built
air conditioner. Several studies have modified microclimate temperature through a variety of
methods. However, changing the microclimate RH at a controlled rate and observing the
effect on user perception has not been undertaken before to the authors’ knowledge. It was
hypothesised that modifying the microclimate RH would influence both the subjects’ skin
temperature as well as their thermal perception and further that changes in both the
temperature and perception would be dependant upon rate of change of RH in that
microclimate.
METHODS
The protocol was approved by the University of Portsmouth Ethics Committee and written
consent was obtained from all subjects. Eight active males aged (mean ±SE) 22.5 ± 3.5 y.,
mass 74.78 ± 8.10kg, completed two trials where perceptual measurements of their
temperature sensation (TS), torso temperature sensation (TTS), thermal comfort (TC), torso
thermal comfort (TTC), skin wettedness (SW), and torso skin wettedness (TSW) were
assessed, either as directed or
every 4 minutes while walking
on a treadmill (5km.h -1 , 1%
incline) in a warm environment
(33 o C, 50% RH) for between
106-114 minutes. Physiological
measurements included 12 skin
temperatures (chest, shoulder,
upper back, lower back,
abdomen, forehead, forearm,
hand, foot, upper thigh, calf,
lower leg) 6 microclimate RH
sites (vest inlet, vest lower
right, abdomen, chest, upper
back, lower back); core
temperature was monitored using a rectal thermistor inserted 15cm beyond the anal sphincter,
356
% Relative Humidity
90
80
70
60
50
40
30
20
10
0
Figure 1: Profiles of Input Relative Humidity Ramps for Vest
15%/min 4%/min
7%/min 2%/min
0 20 40 60 80 100 120
Test Time Minutes