Vaisala HMK15 - Manual (Page 14)

User's Guide ________________________________________________________
12 _____________________________________________________M210185EN-C
- At the bottom of the salt chamber there must not be more
than 1 cm of undissolved salt and liquid. Otherwise, the
sensor to be calibrated can be immersed into the solution.
If necessary, verify the amount for example with the
measurement spoon.
- Various standards (ASTM E104-85, DIN 50008, JIS
Z8806) include recommendations and instructions on
how to prepare and store salt solutions.
Preparing the Solutions
Lithium chloride generates a reference humidity of
approximately 11 %RH. It is normally used as the dry end
(offset) reference.
NOTE Never add water to dry LiCl salt; the salt may heat up so
rapidly that it splashes out of the chamber.
NOTE LiCl is harmful when swallowed; the solution is also
corrosive.
NOTE If the LiCl solution is used or stored in temperatures below
+18°C, its equilibrium humidity changes permanently.
Magnesium chloride generates a reference humidity of
approximately 33 %RH. It is often used as a check point if
calibration is performed at more than two points.
Sodium chloride generates a reference humidity of
approximately 75 %RH. It is used as the wet end reference
(gain) for probes measuring in applications with normal
humidities.