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Ventilation Design Handbook on Animal Research Facilities Using Static Microisolators 
Thermocouple Calibration 
During all of the results sets, the cage housed the same six T-type thermocouples. The 
thermocouples were calibrated at five temperatures using a water bath. Water bath temperatures 
were determined using a SAM A thermometer. Regressions were formed by comparing 
thermocouple readings to the thermometer readings. The thermocouples were connected to a 
Campbell 2 lx data logger when readings were taken. The regression equations were used to 
obtain predicted temperature readings. The standard error of the predicted readings vs. the 
thermometer readings was computed for each thermocouple. No standard error reading exceeded 
9.0e-2 °C (1.6e-l °F ). Calibration results are presented in appendix I: section 2.1.1. 
Cage Anemometer Calibration 
BESS Lab thermal anemometer probes surrounded the cage for each result set. The sensors were 
calibrated using a TSI model 8390 Bench Top Wind Tunnel with a TSI model 8910 pressure 
transducer. Because of the relationship between anemometer performance and temperature, the 
calibration air was recycled in a closed loop to prevent temperature fluctuations. This was done 
by having the intake air of the calibrator come from an 2.44 m (8') x 1.22m (4') x 1.22 m (4') x 
5.08e-2m (2") thick insulated box and directing the exhaust air back into the box (see figure 
4.17). The insulated box was cooled for at least ten minutes using air from a chiller to about 
20.0 °C (68.0 °F) at that time the box was sealed and the calibration started. The temperature was 
allowed to rise by conduction until a temperature near room temperature was reached. At this 
time a low power electric heater was turned on to obtain temperatures greater than room 
temperature. Each probe was subjected to velocities of 15, 20, 30, 40 and 50 fpm (0.076, 0.10, 
0.15, 0.20, 0.25 m/s) and temperatures ranged from 20.0 °C to 29.3 °C (68.0 to 84.7 °F). 
Velocities within the calibrator were precisely calculated by the manufacturer and presented in a 
table that relates pressure differences to chamber velocities. Temperature and velocity sensor 
output voltage were taken every second and averaged over one minute using a Campbell 2 lx 
Data Logger. 
Temperature and voltage data were analyzed to form trend lines for each velocity. The trend 
lines were used to generate predicted voltage values. The velocity data, temperature data, and 
predicted voltage values were then combined and plotted to form a contour map that had axes of 
velocity, temperature, and contours of voltage. The map was made using a third order 
polynomial regression. A third order polynomial regression was chosen because it provided an 
equation that could easily be used to determine velocity values within a spreadsheet and because 
it displayed contour lines that closely followed those lines displayed by other curve-fit methods. 
The contour map was made as a visual means of finding if values were not outside the 
calibration range, i.e. greater than 0.25 m/s (50 fpm) or less than 0.10 m/s (20 fpm). Calibration 
results are presented in appendix I: section 2.1.2. 
