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Kestrel 3500FW Fire Weather Meter 0835FWORA

Original price $323.99
Original price $323.99 - Original price $323.99
Original price $323.99
Current price $299.00
$299.00 - $299.00
Current price $299.00

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Kestrel 3500FW Fire Weather Meter Quick look

  • Rugged, simple and accurate wind speed, temperature, humidity, and pressure meter.
  • Calculates relative humidity, temperature, average wind speed, altitude, pressure trends and more.
  • Data hold feature, clock and backlit display for night time use.
  • Includes a waterproof PIG/FDFM reference card. Perfect for taking fire weather observations.

Kestrel 3500FW Fire Weather Meter Overview

When fighting wild fires, protecting lives, houses, and property while ensuring safety for everyone involved demands accurate fire behavior predictions based upon good weather observations. Kestrel weather meters have been relied upon by fire fighters for decades to provide fast, accurate measurement of wind speed, temperature and humidity. The Kestrel 3500 Fire Weather Meter has been updated specifically for fire fighting, adding barometric pressure, altitude and wet bulb readings and an easy-to-read Probability of Ignition (PIG) and Fine Dead Fuel Moisture (FDFM) reference card – everything required for a complete weather observation.  This one rugged, handheld instrument easily replaces all of the items included in your Belt Weather Kit, providing consistently accurate measurements without prepping a sling psychrometer or risking the possibility of human error.

IP67 waterproof and Mil-SPEC-810G drop tested, Kestrels are built for the abuse that work on a fire line can dish out. The Kestrel 3500 Fire Weather Meter includes a hard, rubberized slip-on cover that protects the display and impeller, even when tossed in your pack. Kestrel Weather & Environmental Meters are designed & manufactured in the U.S.A and are backed by our 5-year warranty. Each Kestrel 3500 is factory calibrated and comes with a certificate of conformity and may be factory or field recalibrated.

Environmental Measures

  • Altitude (Barometric)
  • Barometric Pressure
  • Dew Point Temperature
  • Heat Stress Index
  • Relative Humidity
  • Temperature
  • Wet Bulb Temperature (Psychrometric)
  • Wind Chill
  • Wind Speed/Air Speed

Features

  • 3-Button Control
  • Backlight blue white
  • Data Hold Function
  • Date & Time
  • Drop-Tested to MIL-STD-810G
  • Field Humidity Calibration/Correction Routine
  • Hard Slip-On Protective Cover
  • High Contrast, Sunlight Readable Monochrome LCD Display
  • Minimum/Maximum/Average Reading
  • Pressure Sensor
  • Relative Humidity Sensor
  • Temperature Sensor (Patented External Isolated)
  • Waterproof to IP67 (3'/1M for 30 minutes)

Includes

  • Battery - 1 x CR2032
  • Certificate Of Conformity (Spec Sheet)
  • Instructions
  • Lanyard
  • PIG Reference Card (Waterproof)
Specifications
SENSORS
SENSORS 1
0
0
0
2
0
0
0
2
5
0
0
3
0
0
0
3
5
0
0
3
5
0
0
D
T
ACCURACY
(+/-)*
RESOLUTION SPEC. RANGE OP. RANGE NOTES
Wind Speed | Air Flow Larger of 3% of reading, least significant digit or 20 ft/min 0.1 m/s
1 ft/min
0.1 km/h
0.1 mph
0.1 knots
1 B*
0.1 F/S*
0.6 to 40.0 m/s
118 to 7,874 ft/min
2.2 to 144.0 km/h
1.3 to 89.5 mph
1.2 to 77.8 knots
0 to 12 B*
2-131.2 F/S*
0.6 to 60.0 m/s
118 to 11,811 ft/min
2.2 to 216.0 km/h
1.3 to 134.2 mph
1.2 to 116.6 knots
0 to 12 B*
2-196.9 F/S*
1 inch|25 mm diameter impeller with precision axle and low-friction Zytel® bearings. Startup speed stated as lower limit, readings may be taken down to 0.4 m/s | 79 ft/min | 1.5 km/h | .9 mph | .8 kt after impeller startup. Off-axis accuracy -1% @ 5º off-axis; -2% @ 10º; -3% @ 15º. Calibration drift < 1% after 100 hours use at 16 MPH | 7 m/s. Replacement impeller (NK PN-0801) field installs without tools (US Patent 5,783,753). Wind speed calibration and testing should be done with triangle on impeller located at the top front face of the Kestrel. *F/S only in Ballistics units. Beaufort not available in Ballistics units.
Ambient Temperature 0.9 °F
0.5 °C
0.1 °F
0.1 °C
-20.0 to 158.0 °F
-29.0 to 70.0 °C
14.0.0 to 131.0 °F
-10.0 to 55.0 °C
Hermetically sealed, precision thermistor mounted externally and thermally isolated (US Patent 5,939,645) for rapid response. Airflow of 2.2 mph|1 m/s or greater provides fastest response and reduction of insolation effect. Calibration drift negligible. Thermistor may also be used to measure temperature of water or snow by submerging thermistor portion into material -- remove impeller prior to taking submerged measurements and ensure humidity sensor membrane is free of liquid water prior to taking humidity-based measurements after submersion.
Relative Humidity 3.0 %RH 0.1 %RH 5 to 95%
non-condensing
0 to 100% Polymer capacitive humidity sensor mounted in thin-walled chamber external to case for rapid, accurate response (US Patent 6,257,074). To achieve stated accuracy, unit must be permitted to equilibrate to external temperature when exposed to large, rapid temperature changes and be kept out of direct sunlight. Calibration drift +/- 2% over 24 months. Humidity sensor may be recalibrated at factory or in field using Kestrel Humidity Calibration Kit (NK PN-0802).
Pressure 1.5hPa|mbar
0.044 inHg
0.022 PSI
0.1 hPa|mbar
0.01 inHg
0.01 PSI
25°C/ 77°F
750-1100 hPa|mbar
22.15-32.48 inHg
10.88-15.95 PS
0.30 to 48.87 inHg
10.0 to 1654.7
hPa|mbar
0.14 to 24.00 PSI
and
14.0 to 131.0 °F
-10.0 to 55.0 °C
Monolithic silicon piezoresistive pressure sensor with second-order temperature correction. Pressure sensor may be recalibrated at factory or in field. Adjustable reference altitude allows display of station pressure or barometric pressure corrected to MSL. Kestrel 4200 displays station pressure on a dedicated screen. Kestrel 2500 and 3500 display continuously updating three-hour barometric pressure trend indicator: rising rapidly, rising, steady, falling, falling rapidly. Kestrel 4000 series displays pressure trend through graphing function. PSI display on Kestrel 4000 series only.
Compass
1/16th Cardinal
Scale
0 to 360° 0 to 360° 2-axis solid-state magnetoresistive sensor mounted perpendicular to unit plane. Accuracy of sensor dependent upon unit's vertical position. Self-calibration routine eliminates magnetic error from batteries or unit and must be run after every full power-down (battery removal or change). Readout indicates direction to which the back of the unit is pointed when held in a vertical orientation. Declination/variation adjustable for True North readout.


CALCULATED MEASUREMENTS
MEASUREMENT 1
0
0
0
2
0
0
0
2
5
0
0
3
0
0
0
3
5
0
0
3
5
0
0
D
T
ACCURACY
(+/-)*
RESOLUTION SPEC. RANGE SENSORS EMPLOYED NOTES
Altitude typical:
23.6ft/7.2m
max:
48.2ft/14.7m
1ft
1m
typical:
750 to 1100 mBar
max:
300 to 750 mBar
Pressure User Input (Reference Pressure) Height above Mean Sea Level ("MSL"). Temperature compensated pressure (barometric) altimeter requires accurate reference barometric pressure to produce maximum absolute accuracy. Both accuracy specs corresponds to a reference pressure anywhere from 850 to 1100 mBar.
Barometric Pressure 0.07 inHg
2.4 hPa|mbar
0.03 PSI
0.01 inHg
0.1 hPa|mbar
0.01 PSI
Refer to Ranges for Sensors Employed Pressure User Input (Reference Altitude) Air pressure that would be present in identical conditions at MSL. Station pressure compensated for local elevation provided by reference altitude. Requires accurate reference altitude to produce maximum absolute accuracy
Delta T 3.2 °F
1.8 °C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Temperature
Relative Humidity
Pressure
Difference between dry bulb temperature and wet bulb temperature. When spraying, indicates evaporation rate and droplet lifetime. Safe range for pesticide spraying is 4 to 16 °F / 2 to 9 °C.
Dew Point 3.4 °F
1.9 °C
0.1 °F
0.1 °C
15 to 95 % RH
Refer to Range for Temperature Sensor
Temperature Relative Humidity Temperature that a volume of air must be cooled to at constant pressure for the water vapor present to condense into dew and form on a solid surface. Can also be considered to be the water-to-air saturation temperature.
Heat Index 7.1°F
4.0°C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Temperature Relative Humidity Perceived temperature resulting from the combined effect of temperature and relative humidity. Calculated based on NWS Heat Index (HI) tables. Measurement range limited by extent of published tables
Wet Bulb Temperature - Psychrometric 1.6 °F
0.9 °C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Temperature
Relative Humidity
Pressure
Temperature indicated by a sling psychrometer. Due to nature of the psychrometric ratio for a water-air system, this approximates the thermodynamic wet-bulb temperature. The thermodynamic wet-bulb temperature is the temperature a parcel of air would have if cooled adiabatically to saturation temperature via water evaporating into it.
Wind Chill 1.6 °F
0.9 °C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Wind Speed
Temperature
Perceived temperature resulting from combined effect of wind speed and temperature. Calculated based on the NWS Wind Chill Temperature (WCT) Index, revised 2001, with wind speed adjusted by a factor of 1.5 to yield equivalent results to wind speed measured at 10m above ground. Measurement range limited by extent of published tables.


ADDITIONAL SPECIFICATIONS
MEASUREMENT 1
0
0
0
2
0
0
0
2
5
0
0
3
0
0
0
3
5
0
0
3
5
0
0
D
T
NOTES
Display & Backlight Reflective 3 1/2 digit LCD. Digit height 0.36 in / 9 mm. Aviation green electroluminescent backlight. Manual activation with auto-off
Reflective 5 digit LCD. Digit height 0.36 in / 9 mm. Choice of aviation green or visible red (NV models only) electroluminescent backlight. Manual activation with auto-off.
Response Time & Display Update All measurements except those based on relative humidity respond accurately within 1 second. Relative humidity and all measurements which include RH in their calculation may require as long as 1 minute to fully equilibrate to a large change in the measurement environment. Display updates every 1 second.
Max/Avg Wind One-button clear and restart of Max Wind Gust and Average Wind measurement.
Data Upload & Bluetooth® Data Connect Option Requires optional PC interface (USB or RS-232) or Bluetooth data transfer option and provided software.
Bluetooth Data Transfer Option: Adjustable power consumption and radio range from up to 30 ft | 9 meters. Individual unit ID and 4-digit PIN code preprogrammed for easy identification and data security when pairing and transmitting. Employs Bluetooth Serial Port Protocol for data transmission.
Clock / Calendar Real-time hours:minutes clock.
Auto Shutdown After 45 minutes of no key presses.
Languages English
Certifications CE certified, RoHS and WEEE compliant. Individually tested to NIST-traceable standards (written certificate of tests available at additional charge).
Origin Designed and manufactured in the USA from US and imported components. Complies with Regional Value Content and Tariff Code Transformation requirements for NAFTA Preference Criterion B.
Battery Life CR2032, one, included. Average life, 300 hours. Battery life reduced by backlight use in 2000 to 3500 models.
Shock Resistance MIL-STD-810g, Transit Shock, Method 516.6 Procedure IV; unit only; impact may damage replaceable impeller.
Sealing Waterproof (IP67 and NEMA-6).
Operational Temperature Limits 14° F to 131° F | -10 °C to 55 °C Measurements may be taken beyond the limits of the operational temperature range of the display and batteries by maintaining the unit within the operational range and exposing it to the more extreme environment for the minimum time necessary to take reading.
Storage Temperature -22.0 °F to 140.0 °F | -30.0 °C to 60.0 °C.
Size & Weight 4.8 x 1.9 x 1.1 in / 12.2 x 4.8 x 2.8 cm, 3.6 oz / 102 g (including slip-on cover).

* NOTE: Accuracy calculated as uncertainty of the measurement derived from statistical analysis considering the combined effects from primary sensor specifications, circuit conversions, and all other sources of error using a coverage factor of k=2, or two standard deviations (2Σ).

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Kestrel 3500FW Fire Weather Meter Quick look

  • Rugged, simple and accurate wind speed, temperature, humidity, and pressure meter.
  • Calculates relative humidity, temperature, average wind speed, altitude, pressure trends and more.
  • Data hold feature, clock and backlit display for night time use.
  • Includes a waterproof PIG/FDFM reference card. Perfect for taking fire weather observations.

Kestrel 3500FW Fire Weather Meter Overview

When fighting wild fires, protecting lives, houses, and property while ensuring safety for everyone involved demands accurate fire behavior predictions based upon good weather observations. Kestrel weather meters have been relied upon by fire fighters for decades to provide fast, accurate measurement of wind speed, temperature and humidity. The Kestrel 3500 Fire Weather Meter has been updated specifically for fire fighting, adding barometric pressure, altitude and wet bulb readings and an easy-to-read Probability of Ignition (PIG) and Fine Dead Fuel Moisture (FDFM) reference card – everything required for a complete weather observation.  This one rugged, handheld instrument easily replaces all of the items included in your Belt Weather Kit, providing consistently accurate measurements without prepping a sling psychrometer or risking the possibility of human error.

IP67 waterproof and Mil-SPEC-810G drop tested, Kestrels are built for the abuse that work on a fire line can dish out. The Kestrel 3500 Fire Weather Meter includes a hard, rubberized slip-on cover that protects the display and impeller, even when tossed in your pack. Kestrel Weather & Environmental Meters are designed & manufactured in the U.S.A and are backed by our 5-year warranty. Each Kestrel 3500 is factory calibrated and comes with a certificate of conformity and may be factory or field recalibrated.

Environmental Measures

  • Altitude (Barometric)
  • Barometric Pressure
  • Dew Point Temperature
  • Heat Stress Index
  • Relative Humidity
  • Temperature
  • Wet Bulb Temperature (Psychrometric)
  • Wind Chill
  • Wind Speed/Air Speed

Features

  • 3-Button Control
  • Backlight blue white
  • Data Hold Function
  • Date & Time
  • Drop-Tested to MIL-STD-810G
  • Field Humidity Calibration/Correction Routine
  • Hard Slip-On Protective Cover
  • High Contrast, Sunlight Readable Monochrome LCD Display
  • Minimum/Maximum/Average Reading
  • Pressure Sensor
  • Relative Humidity Sensor
  • Temperature Sensor (Patented External Isolated)
  • Waterproof to IP67 (3'/1M for 30 minutes)

Includes

  • Battery - 1 x CR2032
  • Certificate Of Conformity (Spec Sheet)
  • Instructions
  • Lanyard
  • PIG Reference Card (Waterproof)
SENSORS
SENSORS 1
0
0
0
2
0
0
0
2
5
0
0
3
0
0
0
3
5
0
0
3
5
0
0
D
T
ACCURACY
(+/-)*
RESOLUTION SPEC. RANGE OP. RANGE NOTES
Wind Speed | Air Flow Larger of 3% of reading, least significant digit or 20 ft/min 0.1 m/s
1 ft/min
0.1 km/h
0.1 mph
0.1 knots
1 B*
0.1 F/S*
0.6 to 40.0 m/s
118 to 7,874 ft/min
2.2 to 144.0 km/h
1.3 to 89.5 mph
1.2 to 77.8 knots
0 to 12 B*
2-131.2 F/S*
0.6 to 60.0 m/s
118 to 11,811 ft/min
2.2 to 216.0 km/h
1.3 to 134.2 mph
1.2 to 116.6 knots
0 to 12 B*
2-196.9 F/S*
1 inch|25 mm diameter impeller with precision axle and low-friction Zytel® bearings. Startup speed stated as lower limit, readings may be taken down to 0.4 m/s | 79 ft/min | 1.5 km/h | .9 mph | .8 kt after impeller startup. Off-axis accuracy -1% @ 5º off-axis; -2% @ 10º; -3% @ 15º. Calibration drift < 1% after 100 hours use at 16 MPH | 7 m/s. Replacement impeller (NK PN-0801) field installs without tools (US Patent 5,783,753). Wind speed calibration and testing should be done with triangle on impeller located at the top front face of the Kestrel. *F/S only in Ballistics units. Beaufort not available in Ballistics units.
Ambient Temperature 0.9 °F
0.5 °C
0.1 °F
0.1 °C
-20.0 to 158.0 °F
-29.0 to 70.0 °C
14.0.0 to 131.0 °F
-10.0 to 55.0 °C
Hermetically sealed, precision thermistor mounted externally and thermally isolated (US Patent 5,939,645) for rapid response. Airflow of 2.2 mph|1 m/s or greater provides fastest response and reduction of insolation effect. Calibration drift negligible. Thermistor may also be used to measure temperature of water or snow by submerging thermistor portion into material -- remove impeller prior to taking submerged measurements and ensure humidity sensor membrane is free of liquid water prior to taking humidity-based measurements after submersion.
Relative Humidity 3.0 %RH 0.1 %RH 5 to 95%
non-condensing
0 to 100% Polymer capacitive humidity sensor mounted in thin-walled chamber external to case for rapid, accurate response (US Patent 6,257,074). To achieve stated accuracy, unit must be permitted to equilibrate to external temperature when exposed to large, rapid temperature changes and be kept out of direct sunlight. Calibration drift +/- 2% over 24 months. Humidity sensor may be recalibrated at factory or in field using Kestrel Humidity Calibration Kit (NK PN-0802).
Pressure 1.5hPa|mbar
0.044 inHg
0.022 PSI
0.1 hPa|mbar
0.01 inHg
0.01 PSI
25°C/ 77°F
750-1100 hPa|mbar
22.15-32.48 inHg
10.88-15.95 PS
0.30 to 48.87 inHg
10.0 to 1654.7
hPa|mbar
0.14 to 24.00 PSI
and
14.0 to 131.0 °F
-10.0 to 55.0 °C
Monolithic silicon piezoresistive pressure sensor with second-order temperature correction. Pressure sensor may be recalibrated at factory or in field. Adjustable reference altitude allows display of station pressure or barometric pressure corrected to MSL. Kestrel 4200 displays station pressure on a dedicated screen. Kestrel 2500 and 3500 display continuously updating three-hour barometric pressure trend indicator: rising rapidly, rising, steady, falling, falling rapidly. Kestrel 4000 series displays pressure trend through graphing function. PSI display on Kestrel 4000 series only.
Compass
1/16th Cardinal
Scale
0 to 360° 0 to 360° 2-axis solid-state magnetoresistive sensor mounted perpendicular to unit plane. Accuracy of sensor dependent upon unit's vertical position. Self-calibration routine eliminates magnetic error from batteries or unit and must be run after every full power-down (battery removal or change). Readout indicates direction to which the back of the unit is pointed when held in a vertical orientation. Declination/variation adjustable for True North readout.


CALCULATED MEASUREMENTS
MEASUREMENT 1
0
0
0
2
0
0
0
2
5
0
0
3
0
0
0
3
5
0
0
3
5
0
0
D
T
ACCURACY
(+/-)*
RESOLUTION SPEC. RANGE SENSORS EMPLOYED NOTES
Altitude typical:
23.6ft/7.2m
max:
48.2ft/14.7m
1ft
1m
typical:
750 to 1100 mBar
max:
300 to 750 mBar
Pressure User Input (Reference Pressure) Height above Mean Sea Level ("MSL"). Temperature compensated pressure (barometric) altimeter requires accurate reference barometric pressure to produce maximum absolute accuracy. Both accuracy specs corresponds to a reference pressure anywhere from 850 to 1100 mBar.
Barometric Pressure 0.07 inHg
2.4 hPa|mbar
0.03 PSI
0.01 inHg
0.1 hPa|mbar
0.01 PSI
Refer to Ranges for Sensors Employed Pressure User Input (Reference Altitude) Air pressure that would be present in identical conditions at MSL. Station pressure compensated for local elevation provided by reference altitude. Requires accurate reference altitude to produce maximum absolute accuracy
Delta T 3.2 °F
1.8 °C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Temperature
Relative Humidity
Pressure
Difference between dry bulb temperature and wet bulb temperature. When spraying, indicates evaporation rate and droplet lifetime. Safe range for pesticide spraying is 4 to 16 °F / 2 to 9 °C.
Dew Point 3.4 °F
1.9 °C
0.1 °F
0.1 °C
15 to 95 % RH
Refer to Range for Temperature Sensor
Temperature Relative Humidity Temperature that a volume of air must be cooled to at constant pressure for the water vapor present to condense into dew and form on a solid surface. Can also be considered to be the water-to-air saturation temperature.
Heat Index 7.1°F
4.0°C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Temperature Relative Humidity Perceived temperature resulting from the combined effect of temperature and relative humidity. Calculated based on NWS Heat Index (HI) tables. Measurement range limited by extent of published tables
Wet Bulb Temperature - Psychrometric 1.6 °F
0.9 °C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Temperature
Relative Humidity
Pressure
Temperature indicated by a sling psychrometer. Due to nature of the psychrometric ratio for a water-air system, this approximates the thermodynamic wet-bulb temperature. The thermodynamic wet-bulb temperature is the temperature a parcel of air would have if cooled adiabatically to saturation temperature via water evaporating into it.
Wind Chill 1.6 °F
0.9 °C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Wind Speed
Temperature
Perceived temperature resulting from combined effect of wind speed and temperature. Calculated based on the NWS Wind Chill Temperature (WCT) Index, revised 2001, with wind speed adjusted by a factor of 1.5 to yield equivalent results to wind speed measured at 10m above ground. Measurement range limited by extent of published tables.


ADDITIONAL SPECIFICATIONS
MEASUREMENT 1
0
0
0
2
0
0
0
2
5
0
0
3
0
0
0
3
5
0
0
3
5
0
0
D
T
NOTES
Display & Backlight Reflective 3 1/2 digit LCD. Digit height 0.36 in / 9 mm. Aviation green electroluminescent backlight. Manual activation with auto-off
Reflective 5 digit LCD. Digit height 0.36 in / 9 mm. Choice of aviation green or visible red (NV models only) electroluminescent backlight. Manual activation with auto-off.
Response Time & Display Update All measurements except those based on relative humidity respond accurately within 1 second. Relative humidity and all measurements which include RH in their calculation may require as long as 1 minute to fully equilibrate to a large change in the measurement environment. Display updates every 1 second.
Max/Avg Wind One-button clear and restart of Max Wind Gust and Average Wind measurement.
Data Upload & Bluetooth® Data Connect Option Requires optional PC interface (USB or RS-232) or Bluetooth data transfer option and provided software.
Bluetooth Data Transfer Option: Adjustable power consumption and radio range from up to 30 ft | 9 meters. Individual unit ID and 4-digit PIN code preprogrammed for easy identification and data security when pairing and transmitting. Employs Bluetooth Serial Port Protocol for data transmission.
Clock / Calendar Real-time hours:minutes clock.
Auto Shutdown After 45 minutes of no key presses.
Languages English
Certifications CE certified, RoHS and WEEE compliant. Individually tested to NIST-traceable standards (written certificate of tests available at additional charge).
Origin Designed and manufactured in the USA from US and imported components. Complies with Regional Value Content and Tariff Code Transformation requirements for NAFTA Preference Criterion B.
Battery Life CR2032, one, included. Average life, 300 hours. Battery life reduced by backlight use in 2000 to 3500 models.
Shock Resistance MIL-STD-810g, Transit Shock, Method 516.6 Procedure IV; unit only; impact may damage replaceable impeller.
Sealing Waterproof (IP67 and NEMA-6).
Operational Temperature Limits 14° F to 131° F | -10 °C to 55 °C Measurements may be taken beyond the limits of the operational temperature range of the display and batteries by maintaining the unit within the operational range and exposing it to the more extreme environment for the minimum time necessary to take reading.
Storage Temperature -22.0 °F to 140.0 °F | -30.0 °C to 60.0 °C.
Size & Weight 4.8 x 1.9 x 1.1 in / 12.2 x 4.8 x 2.8 cm, 3.6 oz / 102 g (including slip-on cover).

* NOTE: Accuracy calculated as uncertainty of the measurement derived from statistical analysis considering the combined effects from primary sensor specifications, circuit conversions, and all other sources of error using a coverage factor of k=2, or two standard deviations (2Σ).

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Kestrel 3500FW Fire Weather Meter Quick look

  • Rugged, simple and accurate wind speed, temperature, humidity, and pressure meter.
  • Calculates relative humidity, temperature, average wind speed, altitude, pressure trends and more.
  • Data hold feature, clock and backlit display for night time use.
  • Includes a waterproof PIG/FDFM reference card. Perfect for taking fire weather observations.

Kestrel 3500FW Fire Weather Meter Overview

When fighting wild fires, protecting lives, houses, and property while ensuring safety for everyone involved demands accurate fire behavior predictions based upon good weather observations. Kestrel weather meters have been relied upon by fire fighters for decades to provide fast, accurate measurement of wind speed, temperature and humidity. The Kestrel 3500 Fire Weather Meter has been updated specifically for fire fighting, adding barometric pressure, altitude and wet bulb readings and an easy-to-read Probability of Ignition (PIG) and Fine Dead Fuel Moisture (FDFM) reference card – everything required for a complete weather observation.  This one rugged, handheld instrument easily replaces all of the items included in your Belt Weather Kit, providing consistently accurate measurements without prepping a sling psychrometer or risking the possibility of human error.

IP67 waterproof and Mil-SPEC-810G drop tested, Kestrels are built for the abuse that work on a fire line can dish out. The Kestrel 3500 Fire Weather Meter includes a hard, rubberized slip-on cover that protects the display and impeller, even when tossed in your pack. Kestrel Weather & Environmental Meters are designed & manufactured in the U.S.A and are backed by our 5-year warranty. Each Kestrel 3500 is factory calibrated and comes with a certificate of conformity and may be factory or field recalibrated.

Environmental Measures

  • Altitude (Barometric)
  • Barometric Pressure
  • Dew Point Temperature
  • Heat Stress Index
  • Relative Humidity
  • Temperature
  • Wet Bulb Temperature (Psychrometric)
  • Wind Chill
  • Wind Speed/Air Speed

Features

  • 3-Button Control
  • Backlight blue white
  • Data Hold Function
  • Date & Time
  • Drop-Tested to MIL-STD-810G
  • Field Humidity Calibration/Correction Routine
  • Hard Slip-On Protective Cover
  • High Contrast, Sunlight Readable Monochrome LCD Display
  • Minimum/Maximum/Average Reading
  • Pressure Sensor
  • Relative Humidity Sensor
  • Temperature Sensor (Patented External Isolated)
  • Waterproof to IP67 (3'/1M for 30 minutes)

Includes

  • Battery - 1 x CR2032
  • Certificate Of Conformity (Spec Sheet)
  • Instructions
  • Lanyard
  • PIG Reference Card (Waterproof)
SENSORS
SENSORS 1
0
0
0
2
0
0
0
2
5
0
0
3
0
0
0
3
5
0
0
3
5
0
0
D
T
ACCURACY
(+/-)*
RESOLUTION SPEC. RANGE OP. RANGE NOTES
Wind Speed | Air Flow Larger of 3% of reading, least significant digit or 20 ft/min 0.1 m/s
1 ft/min
0.1 km/h
0.1 mph
0.1 knots
1 B*
0.1 F/S*
0.6 to 40.0 m/s
118 to 7,874 ft/min
2.2 to 144.0 km/h
1.3 to 89.5 mph
1.2 to 77.8 knots
0 to 12 B*
2-131.2 F/S*
0.6 to 60.0 m/s
118 to 11,811 ft/min
2.2 to 216.0 km/h
1.3 to 134.2 mph
1.2 to 116.6 knots
0 to 12 B*
2-196.9 F/S*
1 inch|25 mm diameter impeller with precision axle and low-friction Zytel® bearings. Startup speed stated as lower limit, readings may be taken down to 0.4 m/s | 79 ft/min | 1.5 km/h | .9 mph | .8 kt after impeller startup. Off-axis accuracy -1% @ 5º off-axis; -2% @ 10º; -3% @ 15º. Calibration drift < 1% after 100 hours use at 16 MPH | 7 m/s. Replacement impeller (NK PN-0801) field installs without tools (US Patent 5,783,753). Wind speed calibration and testing should be done with triangle on impeller located at the top front face of the Kestrel. *F/S only in Ballistics units. Beaufort not available in Ballistics units.
Ambient Temperature 0.9 °F
0.5 °C
0.1 °F
0.1 °C
-20.0 to 158.0 °F
-29.0 to 70.0 °C
14.0.0 to 131.0 °F
-10.0 to 55.0 °C
Hermetically sealed, precision thermistor mounted externally and thermally isolated (US Patent 5,939,645) for rapid response. Airflow of 2.2 mph|1 m/s or greater provides fastest response and reduction of insolation effect. Calibration drift negligible. Thermistor may also be used to measure temperature of water or snow by submerging thermistor portion into material -- remove impeller prior to taking submerged measurements and ensure humidity sensor membrane is free of liquid water prior to taking humidity-based measurements after submersion.
Relative Humidity 3.0 %RH 0.1 %RH 5 to 95%
non-condensing
0 to 100% Polymer capacitive humidity sensor mounted in thin-walled chamber external to case for rapid, accurate response (US Patent 6,257,074). To achieve stated accuracy, unit must be permitted to equilibrate to external temperature when exposed to large, rapid temperature changes and be kept out of direct sunlight. Calibration drift +/- 2% over 24 months. Humidity sensor may be recalibrated at factory or in field using Kestrel Humidity Calibration Kit (NK PN-0802).
Pressure 1.5hPa|mbar
0.044 inHg
0.022 PSI
0.1 hPa|mbar
0.01 inHg
0.01 PSI
25°C/ 77°F
750-1100 hPa|mbar
22.15-32.48 inHg
10.88-15.95 PS
0.30 to 48.87 inHg
10.0 to 1654.7
hPa|mbar
0.14 to 24.00 PSI
and
14.0 to 131.0 °F
-10.0 to 55.0 °C
Monolithic silicon piezoresistive pressure sensor with second-order temperature correction. Pressure sensor may be recalibrated at factory or in field. Adjustable reference altitude allows display of station pressure or barometric pressure corrected to MSL. Kestrel 4200 displays station pressure on a dedicated screen. Kestrel 2500 and 3500 display continuously updating three-hour barometric pressure trend indicator: rising rapidly, rising, steady, falling, falling rapidly. Kestrel 4000 series displays pressure trend through graphing function. PSI display on Kestrel 4000 series only.
Compass
1/16th Cardinal
Scale
0 to 360° 0 to 360° 2-axis solid-state magnetoresistive sensor mounted perpendicular to unit plane. Accuracy of sensor dependent upon unit's vertical position. Self-calibration routine eliminates magnetic error from batteries or unit and must be run after every full power-down (battery removal or change). Readout indicates direction to which the back of the unit is pointed when held in a vertical orientation. Declination/variation adjustable for True North readout.


CALCULATED MEASUREMENTS
MEASUREMENT 1
0
0
0
2
0
0
0
2
5
0
0
3
0
0
0
3
5
0
0
3
5
0
0
D
T
ACCURACY
(+/-)*
RESOLUTION SPEC. RANGE SENSORS EMPLOYED NOTES
Altitude typical:
23.6ft/7.2m
max:
48.2ft/14.7m
1ft
1m
typical:
750 to 1100 mBar
max:
300 to 750 mBar
Pressure User Input (Reference Pressure) Height above Mean Sea Level ("MSL"). Temperature compensated pressure (barometric) altimeter requires accurate reference barometric pressure to produce maximum absolute accuracy. Both accuracy specs corresponds to a reference pressure anywhere from 850 to 1100 mBar.
Barometric Pressure 0.07 inHg
2.4 hPa|mbar
0.03 PSI
0.01 inHg
0.1 hPa|mbar
0.01 PSI
Refer to Ranges for Sensors Employed Pressure User Input (Reference Altitude) Air pressure that would be present in identical conditions at MSL. Station pressure compensated for local elevation provided by reference altitude. Requires accurate reference altitude to produce maximum absolute accuracy
Delta T 3.2 °F
1.8 °C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Temperature
Relative Humidity
Pressure
Difference between dry bulb temperature and wet bulb temperature. When spraying, indicates evaporation rate and droplet lifetime. Safe range for pesticide spraying is 4 to 16 °F / 2 to 9 °C.
Dew Point 3.4 °F
1.9 °C
0.1 °F
0.1 °C
15 to 95 % RH
Refer to Range for Temperature Sensor
Temperature Relative Humidity Temperature that a volume of air must be cooled to at constant pressure for the water vapor present to condense into dew and form on a solid surface. Can also be considered to be the water-to-air saturation temperature.
Heat Index 7.1°F
4.0°C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Temperature Relative Humidity Perceived temperature resulting from the combined effect of temperature and relative humidity. Calculated based on NWS Heat Index (HI) tables. Measurement range limited by extent of published tables
Wet Bulb Temperature - Psychrometric 1.6 °F
0.9 °C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Temperature
Relative Humidity
Pressure
Temperature indicated by a sling psychrometer. Due to nature of the psychrometric ratio for a water-air system, this approximates the thermodynamic wet-bulb temperature. The thermodynamic wet-bulb temperature is the temperature a parcel of air would have if cooled adiabatically to saturation temperature via water evaporating into it.
Wind Chill 1.6 °F
0.9 °C
0.1 °F
0.1 °C
Refer to Ranges for Sensors Employed Wind Speed
Temperature
Perceived temperature resulting from combined effect of wind speed and temperature. Calculated based on the NWS Wind Chill Temperature (WCT) Index, revised 2001, with wind speed adjusted by a factor of 1.5 to yield equivalent results to wind speed measured at 10m above ground. Measurement range limited by extent of published tables.


ADDITIONAL SPECIFICATIONS
MEASUREMENT 1
0
0
0
2
0
0
0
2
5
0
0
3
0
0
0
3
5
0
0
3
5
0
0
D
T
NOTES
Display & Backlight Reflective 3 1/2 digit LCD. Digit height 0.36 in / 9 mm. Aviation green electroluminescent backlight. Manual activation with auto-off
Reflective 5 digit LCD. Digit height 0.36 in / 9 mm. Choice of aviation green or visible red (NV models only) electroluminescent backlight. Manual activation with auto-off.
Response Time & Display Update All measurements except those based on relative humidity respond accurately within 1 second. Relative humidity and all measurements which include RH in their calculation may require as long as 1 minute to fully equilibrate to a large change in the measurement environment. Display updates every 1 second.
Max/Avg Wind One-button clear and restart of Max Wind Gust and Average Wind measurement.
Data Upload & Bluetooth® Data Connect Option Requires optional PC interface (USB or RS-232) or Bluetooth data transfer option and provided software.
Bluetooth Data Transfer Option: Adjustable power consumption and radio range from up to 30 ft | 9 meters. Individual unit ID and 4-digit PIN code preprogrammed for easy identification and data security when pairing and transmitting. Employs Bluetooth Serial Port Protocol for data transmission.
Clock / Calendar Real-time hours:minutes clock.
Auto Shutdown After 45 minutes of no key presses.
Languages English
Certifications CE certified, RoHS and WEEE compliant. Individually tested to NIST-traceable standards (written certificate of tests available at additional charge).
Origin Designed and manufactured in the USA from US and imported components. Complies with Regional Value Content and Tariff Code Transformation requirements for NAFTA Preference Criterion B.
Battery Life CR2032, one, included. Average life, 300 hours. Battery life reduced by backlight use in 2000 to 3500 models.
Shock Resistance MIL-STD-810g, Transit Shock, Method 516.6 Procedure IV; unit only; impact may damage replaceable impeller.
Sealing Waterproof (IP67 and NEMA-6).
Operational Temperature Limits 14° F to 131° F | -10 °C to 55 °C Measurements may be taken beyond the limits of the operational temperature range of the display and batteries by maintaining the unit within the operational range and exposing it to the more extreme environment for the minimum time necessary to take reading.
Storage Temperature -22.0 °F to 140.0 °F | -30.0 °C to 60.0 °C.
Size & Weight 4.8 x 1.9 x 1.1 in / 12.2 x 4.8 x 2.8 cm, 3.6 oz / 102 g (including slip-on cover).

* NOTE: Accuracy calculated as uncertainty of the measurement derived from statistical analysis considering the combined effects from primary sensor specifications, circuit conversions, and all other sources of error using a coverage factor of k=2, or two standard deviations (2Σ).

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