Fluke 971 Temperature and Humidity Meter

Handheld air temperature and relative humidity meter with dew point and wet-bulb temperature calculation, for assessing environmental conditions in technical rooms and passenger compartments. A protected capacitive sensor responds rapidly to changing conditions.

Unlike wall-mounted thermohygrometers, it has reading memory and minimum/maximum/average modes, enabling documentation of conditions in a container or cabinet throughout an inspection.

In railway signalling containers, dispatch rooms and tunnels, the meter detects moisture conditions that could cause condensation on electronics; in passenger coaches, it helps verify air conditioning and ventilation performance against comfort requirements. An on-site dew point reading indicates whether an enclosure is likely to collect condensation after opening.

Specifications (Fluke 971, from the datasheet):

• Temperature - –20 °C to +60 °C, accuracy ±0.5 °C (0–45 °C), 0.1 °C resolution, NTC sensor
• Relative humidity - 5% to 95%, accuracy ±2.5% (10–90% at 23 °C), 0.1% resolution
• Humidity response time - 60 s to 90% of range at 1 m/s airflow
• Functions - dew point, wet-bulb temperature, min/max/average
• Memory - 99 readings
• Electromagnetic compatibility - EN 61326-1
• Power - 4 AAA batteries, 200 h operation
• Weight - 190 g; dimensions 194 × 60 × 34 mm