Product Manual

22
FDFM – Fine Dead Fuel Moisture, also known as 1 Hr
Moisture Content, is an estimate of the moisture content of
dead fuel between 0-1/4” in diameter.
HEAT INDEX – Heat Index is a calculated value of the
perceived temperature based on temperature and relative
humidity.
GLOBE TEMP – Globe Temperature is dened as the
temperature measured inside a 6-inch copper globe
painted black. On the Kestrel HST, the temperature inside
the 1-inch|25 mm globe is converted to the equivalent
temperature for a standard globe. The closest equivalence
will be obtained with airow greater than 2.2 mph|1 m/s.
NWB TEMP – Natural Wet Bulb Temperature is a measure
of evaporative cooling in an environment with unforced,
naturally occurring air ow.
WBGT – Wet Bulb Globe Temperature is a measure of human
heat stress resulting from the combination of eects due
to temperature, humidity, wind speed (wind chill), and
visible and radiant heat. Outdoor WBGT is calculated from
a weighted sum of Natural Wet Bulb Temperature, Globe
Temperature and dry bulb Temperature.
TWL – Thermal Work Limit is a measure of the heat
energy a person can dissipate from their surface area in
Watts per square meter (w/m2). For more information
on TWL see http://www.tandfonline.com/doi/
abs/10.1080/104732202753438261.
DEW POINT – Dew Point is the temperature at which
water vapor will begin to condense out of the air.
WET BULB – Wet Bulb is the lowest temperature that
can be reached in the existing environment by cooling
through evaporation. Wet Bulb is always equal to or
lower than ambient temperature.
BARO – Barometric Pressure is the local station (or
absolute) pressure with the pressure dierential
associated with the locations altitude above sea level
subtracted. An accurate reading depends on an
accurate initial altitude input and unchanging altitude
while measuring.
ALTITUDE – Altitude is the change in vertical distance
associated with a change in atmospheric pressure.
An accurate reading depends on an accurate initial
barometric pressure input and stable barometric
pressure while measuring.
STATION – Station Pressure (Absolute Pressure) is the
pressure exerted by the earth’s atmosphere at any
given point.
DENS ALT – Density Altitude is the altitude at which
the density of the theoretical standard atmospheric
conditions (ISA) would match the actual local air
density.