AN IMPROVED MOUNTING FOR THERMOCOUPLES FOR THE MEASUREMENT 
OF THE SURFACE TEMPERATURE OF THE BODY* 
by 
Edirard D, Palmes, 1st It., SnC and 
Charles R. Park, Capt., MC 
from 
Medical Department Field Research Laboratory 
Fort Knox, Kentucky, 18 March 19U7 
♦Sub-Project under Studies of Body Reaction and Requirements under 
Varied Environmental and Climatic Conditions. (M.D.F.RoL*-955. Approved 
by CG, ASF, 31 May 19U6. Project No. 55 
MEDEA 
18 March 1947 
ABSTRACT 
AN IMPROVED MOUNTING FOR THERMOCOUPLES FOR THE MEASUREMENT OF THE 
SURFACE TEMPERATURE OF THE BODY 
OBJECT 
The development of thermocouples to measure accurately the 
surface temperature of the body. 
RESULTS 
Thermocouples mounted on copper window screen gave skin temperature 
readings comparable to those obtained by a radiometer. 
CONCLUSIONS 
The surface temperature of the body can be measured easily and 
with accuracy with these thermocouple assemblies. 
RECOMMENDATIONS • 
These thermocouple assemblies are recommended except where the 
greatest precision is necessary. 
Submitted by5 
Edward D. Palmes, 1st Lt., SnC 
Charles R. Park, Capt., MC 
APPROVED^ 
RAyGyTAQGS (1 fl 
of Research 
rtf'* * e^C/ 
APPROVED 
FREDE3I • KNOBLAUCH 
Lt. Colonel, MC 
Comma nding AN IMPROVED MOUNTING FOR THERMOCOUPLES FOR THE MEASUREMENT OF THE 
SURFACE TEMPERATURE OF THE BODY 
I. INTRODUCTION 
The intensity of radiation from the skin, measured by a radiometer, 
provides the best index of the temperature of the outermost surface of 
the body. The radiometer is an accurate instrument but is technically 
difficult to employ; it requires daily calibration, the conversion of 
electrical potentials to temperature is laborious, and an observer or 
trained subject must hold the instrument in position for each reading. 
Thermocouples, on the other hand, are technically easy to use, but are 
often inaccurate for the measurement of surface temperature because of 
the mountings usually employed. If a naked thermal junction is used, 
readings are affected by the temperature of the ambient air, and firm 
contact between the junction and the skin is difficult to maintain. 
When the thermocouple is protected from the air by a covering, heat 
loss from the skin is impeded and the readings are too high. The 
deviation in surface temperature measurements by thermocouple and 
radiometer is generally 1 degree C. to 3 degrees C, (i) „ 
II. EXPERIMENTAL 
A. Apparatus 
It proved possible to develop a thermocouple mounting which 
allowed surface temperature to be determined with much greater accuracy 
than by those previously employed. This mounting (Figure l) was made 
on a 1x3 in. rectangle of copper window screen (l6 mesh, wire diameter 
0.01 in.). Copper-constantan thermocouple leads were used, and kinking 
was prevented by plastic spaghetti. Double cloth insulation was re- 
tained to the point where the wires passed under the screen and single 
cloth and lacquer insulation were continued up to the junction itself. 
The insulated portion of the wire was lashed to the screen with thread. 
The naked leads were twisted together and the junction, one-half inch 
in length, was soldered to the under side of the screen as indicated. 
The screen remained quite flexible except for the ends, which were 
dipped in soft solder to provide firm connections for metal buttons. 
Adjustable bands of elastic cloth were snapped to these buttons and 
held the mounting firmly against the skin. 
B. Results 
Surface temperature measurements using these assemblies were 
compared with readings obtained by radiometer in four different environ- 
ments. .Thermocouples were fastened to the belly, chest, and thighs of 
nude subjects and temperatures on adjacent skin areas were determined 
simultaneously by both methods. The results are shown in Figure 2. 
The broken lines on each side of the central diagonal show the limits FIGURE 1 
THE THERMOCOUPLE ASSEMBLY FIGURE 2 
COMPARISON OF SIMULTANEOUS THERMOCOUPLE AND RADIOMETER 
MEASUREMENTS OF SURFACE TEMPERATURES of variations of ll degree C between the readings and enclose ’ 
of all measurements. Thermocouple and radiometric determinations in 
each environment were then averaged separately and the values compared 
(Table l). 
TABLE 1 
Comparison of Thermocouple and Radiometer Readings 
Room Temp. 
°G 
Number of 
Values 
Avg. Surface 
Temp. °C 
Difference 
°C 
Thermocouple 
Radiometer 
29 
16 
3lt-9 
35.0 
-Ool 
32 
23 
3U.2 
3 It. 2 
0.0 
38 
2k 
35.it 
35.0 
fO.li 
hi 
28 
37.1 
36.5 
' +0.6' 
III. DISCUSSION 
It was apparent that the room temperature still had some effect 
on the thermocouple readings since these were higher than radiometric 
measurements in hot environments. 
IV. CONCLUSIONS 
These assemblies proved satisfactory in many studies of long 
duration. They were easily constructed and quite Strong* A l$rge 
number of mountings could be attached to a subject rapidly and easily, 
and they always remained firmly in place despite heavy sweating and 
muscular movement. 
V. RECOMMENDATIONS 
These thermocouple assemblies are recommended except where the 
greatest precision is necessary. 
VI. BIBLIOGRAPHY 
1. Hardy, J, D,: J. Clin. Investigation 13:609, 193U