Review and Evaluation of Thermal Sensors for Use in Testing Firefighters Protective Clothing. Annual Report.
Review and Evaluation of Thermal Sensors for Use in
Testing Firefighters Protective Clothing. Annual
Report.
(9614 K)
Barker, R. L.; Hamouda, H.; Shalev, I.; Johnson, J.
NIST GCR 99-773; Annual Report; 72 p. March 1999.
Sponsor:
National Institute of Standards and Technology,
Gaithersburg, MD
Available from:
National Technical Information Service
(NTIS), Technology Administration, U.S. Department of
Commerce, Springfield, VA 22161.
Telephone:
1-800-553-6847 or 703-605-6000;
Fax: 703-605-6900.
Website: http://www.ntis.gov
Order number: PB99-140527
Keywords:
fire fighters; protective clothing; sensors; turnout
coats; heat flux; heat sinks; measuring instruments
Abstract:
The Center for Research on Textile Protection and
Comfort (T-PACC) at North Carolina State University
conducted a project which had, as its primary objective,
the selection and evaluation of sensors that can be used
to measure heat transferred through firefighter
protective clothing materials, with the ultimate goal of
applying this knowledge base to the development of
rugged, and dependable laboratory benchtop and fire
scene specific sensor technology. The purpose of this
final report is to summarize the findings of this
project and to recommend future directions in protection
measuring heat flux sensor development. Non-cooled
sensor technology was initially investigated for this
application. A review of state-of-the-art surface heat
flux measuring devices confirmed the existence of a
variety of sensor options, including devices that
utilize buried thermocouple transducers, slug or heat
capacitance calorimeters, thin foil or Gordon
transducers, wafer type thermocouple transducers and
suspended disk thermocouple transducers. Based on stated
applications and instrumental needs, four different
thermal sensors were selected for comparative testing
and evaluation by this program. A fifth sensor called
"Pyrocal", built at NCSU, was included in this project
in order to address the disadvantages encountered in the
available sensors. The Pyrocal sensor is smaller and
far less bulky than the TPP calorimeter having less heat
loss and more rapid response times. Pyrocal has the
additional advantage of possessing a small mass in
comparison to the TPP calorimeter (1.3 grams vs. 17.9
grams). This is an important consideration, since the
smaller mass of the Pyrocal sensor significantly reduced
heat sink effects associated with the use of the TPP
calorimeter. This contributed to improve the accuracy of
the bench top TPP tests when used in sample mounting
configurations that require intimate contact between the
thermal sensor and the test fabric. Although other
existing non-cooled sensors that utilize surface mounted
thermocouples (ThermoMan(r) and Alberta type) performed
comparatively well in our thermal tests, they lacked the
durability in use that can be expected from the Pyrocal
device. Most significantly, the Pyrocal sensor overcomes
a significant drawback associated with existing sensors.
It does not require an inverse heat transfer calculation
to estimate heat flux. This avoids errors associated
with thermocouple location, and the mathematics of the
heat transfer calculations. Direct heat flux
measurements, using the Pyrocal sensor, circumvent these
errors and provide a more accurate direct reading.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899