Humidity calibrators – find manufacturers and suppliers

Humidity calibrators are devices or systems that provide a known, traceable humidity or dew point/relative humidity reference in order to test, adjust or calibrate humidity sensors, hygrometers and humidity measuring chains.

The aim is to accurately determine and document the measurement error under defined conditions so that measuring devices provide reliable measurement results.

Below you will find the functionality, types, measured variables and output forms of humidity calibrators, their areas of application and their advantages:

How humidity calibrators work:

Humidity calibrators generate controlled humidity conditions according to one of two basic principles:

1. Dynamic (flow) generators:
   A known volume of a dry carrier gas (usually air or nitrogen) is mixed with a precisely metered amount of water vapor from humidifiers or steam injectors,.
   Precise flow control allows the concentration of the water vapor and thus the relative humidity to be set exactly.
   Dynamic systems provide good reproducibility and fast changeover times.
2. Static (equilibrium) methods:
   Here, defined humidity conditions are generated via hygroscopic salts, saturated salt solutions at a known temperature, or via controlled temperature/humidity chambers.
   The sample is left in a container until moisture equilibrium is reached.
   This method is simple and inexpensive, but has longer start-up and equilibration times.

Other physical principles used in calibrators or reference devices are dew point generation by precisely determinable water vapor partial pressures and chilled mirror technique, dew point detection by looking at the condensation point on a cooled surface, as a highly accurate reference method.

Types of humidity calibrators:

Different calibrators are available depending on the location and the required accuracy:

1. Portable field calibrators / handheld devices:
   Compact, battery-operated devices for on-site testing (e.g. measuring points in air conditioning and process plants).
   Typical features of these devices are moderate accuracy, fast operation and small size.
2. Table/laboratory calibrators:
   Larger, temperature-stabilized devices with higher accuracy and documentation functions for testing laboratories.
   Often with adjustable temperature and controlled air flow.
3. Saturation/salt calibrators:
   Simple static systems with saturated salt solutions for fixed, known RH values, e.g. 33 %, 75 %.
   Good for reference tests and long-term stability tests.
4. Dynamic generators:
   Precise industrial calibrators that control flow ratios very finely and cover wide RH and temperature ranges.
5. Dewpoint / dew point generators:
   Generate defined dewpoints via controlled water vapor partial pressures.
   Suitable for lower humidities and as a high-precision reference.
6. Combined temperature/humidity calibrators (climate chambers):
   Allow simultaneous control of temperature and humidity; important because relative humidity is highly temperature dependent.
7. Chilled mirror reference devices:
   Are often used as a "primary reference" in laboratories because they directly measure the dew point and provide very stable reference values.

Measured variables and output forms of humidity calibrators:

1. Relative humidity (RH, %): Standard specification for most sensors.
2. Absolute humidity / water vapor partial pressure (g/m³, Pa): More relevant for certain applications (process technology).
3. Dew point (°C): Particularly preferred for low humidity and gaseous systems.

Calibrators often provide digital outputs, test reports and calibration certificates with measurement uncertainty.

Applications of humidity calibrators:

1. Laboratories and calibration facilities:
Traceable calibration according to standards, creation of calibration certificates.

2. Field calibration of installations:
In HVAC systems, clean rooms, pharmaceutical processes, food production, warehouses, e.g. refrigerated logistics.

3. Production and quality assurance:
Inline/end-of-line testing of sensors and devices.

4. Research and environmental monitoring networks:
Meteorological stations, climate research.

5. Validation of measurement chains:
Z. E.g. for environmental data loggers, process controls.

Advantages of using humidity calibrators:

• Improved measurement accuracy and reliability: Direct determination and correction of measurement errors.
• Traceability: Calibrations can be traced back to national/international standards (e.g. PTB, NIST).
• Documentation & compliance: Calibration certificates support ISO/IEC 17025 accreditation, quality management and regulatory requirements.
• Cost savings through preventive maintenance: Early detection of drifting sensors reduces downtime and quality losses.
• Flexibility: Field and laboratory solutions allow calibration without expensive device shipping.
• Estimation of measurement uncertainty: Professional calibrations provide quantified uncertainties that can be incorporated into process decisions.

Moisture calibrators are indispensable tools for calibrating moisture analyzers precisely, traceably and in accordance with standards. By choosing the right type of calibrator - from simple salt solutions to high-precision dew point generators - measurement errors can be minimized, regulatory requirements met and long-term quality, reliability and cost control ensured in all moisture-dependent processes.

Here are the most important aspects to look out for when purchasing humidity calibrators:

Humidity calibrators are key tools for companies that require precise and traceable measurements of humidity values - for example in laboratories, production processes, clean rooms, the food industry or meteorological applications. As humidity calibrators usually represent an investment with a service life of several years, it is important to carefully check whether the device meets the technical, normative and organizational requirements before purchasing. Careful selection not only ensures measurement quality, but also efficiency and long-term cost savings.

• The first step when purchasing is to determine the measuring range and the measured variables for which the calibrator is to be used.
• The calibrator should cover the relevant range of relative humidity, dew point and, if applicable, temperature for your application.
• Check whether it can generate or measure several measured variables simultaneously.
• The specified accuracy must be significantly better than the required accuracy of your sensors.
• Make sure that the measurement uncertainty is specified in full, including temperature stability and pressure conditions, to ensure traceability.
• Ask whether the device is supplied with a traceable calibration certificate, e.g. DAkkS, PTB or NIST.
• A manufacturer who offers regular recalibrations makes it easier to comply with ISO or GMP guidelines later on.
• The generated humidity conditions should remain stable over time and under changing environmental conditions. This is particularly important if several sensors are to be calibrated in parallel.
• As relative humidity is temperature-dependent, the calibrator must have precise temperature control or be able to be integrated into a climate chamber.
• Consider whether you need a device for laboratory applications, field calibrations or both. Portable devices offer mobility, stationary systems usually offer higher accuracy and more automation.
• For mobile use, the device should be compact, shockproof and climate-resistant. For laboratory applications, precision and stability are more important.
• Professional calibrators should offer automatic test sequences, digital data interfaces such as USB, Ethernet, RS-485 and software for logging. This reduces manual work steps and minimizes sources of error.
• Make sure that several sensors can be calibrated at the same time. If the test throughput is high, a system with several connections and fast switchover time between humidity points is worthwhile.
• In addition to the purchase price, the running costs of consumables such as water or salt solutions, maintenance intervals and spare parts are decisive factors.
• Also check whether operation is possible without highly specialized personnel.
• Good manufacturer or dealer support, e.g. hotline, training, calibration and repair service, saves time and money in the event of a problem.
• Check the delivery times for spare parts and accessories.
• Depending on the industry, pharmaceutical, food or environmental technology, specific standards may apply, e.g. ISO 17025, GMP, FDA. The calibrator should be able to document tests that meet these standards.

Purchasing humidity calibrators requires more than just looking at price and basic function. The decisive factors are measuring range, accuracy, traceability, stability, automation and service - in other words, all factors that ensure long-term measurement reliability and operational efficiency. If you clearly define your requirements in advance, carefully compare manufacturers' offers and pay attention to certification and support, you are investing in a device that will not only work reliably and in compliance with standards today, but for many years to come.

Humidity calibrators can be purchased from various suppliers. Comprehensive information about manufacturers and suppliers of Humidity calibrators from all over the world can be found on Exportpages.