Vaisala HMK15 Humidity Calibrator


  • Easy and reliable calibration of humidity probes and transmitters.
  • Based on saturated salt solutions.
  • Fast temperature equilibration.
  • No external power is required.
  • Suitable for laboratory use and on-site checks.
  • Chambers and transit covers make HMK15 easy to transport.
  • Pre-measured certified salts available.
  • Vaisala Service Centers offer accredited calibrations for humidity, temperature, and barometric pressure.

Dpstar is a leading supplier of environmental measurement sensors for temperature, relative humidity, pressure, dew point, CO2, and other environmental condition monitoring for industrial process application and research. Since the ’90s, we earned a reputation as a trusted partner to our clients through our commitment and dedication. We are an authorized distributor and supplier of measuring sensors solutions from renowned manufacturers Vaisala. Vaisala is a global leader in environmental and industrial measurement. Building on 80 years of experience, Vaisala provides observations for a better world. Vaisala is a reliable partner for customers around the world, offering a comprehensive range of innovative observation and measurement products and services.

Vaisala HMK15 simplifies calibration and spot checking of humidity probes and transmitters. However, for critical applications, we recommend calibration at a Vaisala Service Center for the best results.

Key Benefits

  • Easy and reliable calibration of humidity probes and transmitters
  • Suitable for laboratory use and on-site checks
  • No external power required

Method used by leading laboratories

The operating principle of HMK15 is based on the fact that a saturated salt solution generates a certain relative humidity in the air above it. Humidity probes or transmitters can then be calibrated based on these readings. This method is widely used and trusted by leading laboratories for calibrating humidity instruments. Typically, two or three different salt solutions are used, selected based on the specific application.

Certified salts

Vaisala HMK15 can be ordered with certified and pre-measured salts. A sample calibration is made from each batch in Vaisala’s Measurement Standards Laboratory (MSL).

FINAS accredited measurement standards laboratory

Vaisala’s Measurement Standards Laboratory is a FINAS accredited calibration laboratory. FINAS is a member of the EA (the European Cooperation for Accreditation).


Operating Environment
Operating temperature range +0 … +50 °C (+32 … +122 °F)
Mechanical Specifications
Dimensions (H × W × L) 90 × 230 × 200 mm
(3.54 × 9.06 × 7.87 in)
Weight 1 kg (2.20 lb) without salt solutions
Material Anodized aluminum
Standard contents of HMK15 Calibrator
Base plate
Two salt chambers, chamber covers, and transit covers
Measurement cup and mixing spoon
Optional items
See table Spare parts and accessories
Spare Parts &Amp; Accessories
Rubber plug set 19746HM
Salt chamber 19766HM
Ion exchanged water 19767HM
Adapter fitting for 12 mm probes 211302SP
Thermometer with red capillary liquid 25130HM
Transit bag HM27032
Cover set for DMT132/HMP110 with filter 230914
HMK15 chamber lid for 4 × HMP110 with filter 253277SP
Adapter for HMP42 probe HM37067
Certified and ready dosed salts 1)
Ready-dosed LiCl salt package (LiCl salt 11 %RH, total uncertainty ±1.3 %RH) 2) 19729HM
Ready-dosed MgCl2 salt package (MgCl2 salt 33 %RH, total uncertainty ±1.2 %RH) 2) 19730HM
Ready-dosed NaCl salt package (NaCl salt 75 %RH, total uncertainty ±1.5 %RH) 2) 19731HM
Ready-dosed KCl salt package (KCl salt 85 %RH, total uncertainty ±2.0 %RH) 2) 251377HM
Ready-dosed K2SO4 salt package (K2SO4 salt 97 %RH, total uncertainty ±2.0 %RH) 2) 19732HM
1) Calibration certificate included with each salt package.
2) Uncertainties given at +20 °C (+68 °C).


Vaisala HMK15 Series Humidity Calibrator_DpstarGroup