Relative Humidity (RH) Calibration

Did you know?

• Leonardo da Vinci built a crude hygrometer in the 1400s, his work was continued in 1664 by Francesco Folli who invented a more practical model.
  
  
• There are serveral types of hygrometers, the psychometer uses two thermometers in tandem, one with a wetted base and the other with a dry base. The mechanical hygrometer is based on the idea that organic substances contract and expand in response to humidity. Electrical hygrometers have been devised to use semiconductors that measure resistance.

Relative humidity is significant in many aspects of everyday life. It is measured as part of health and safety requirements as well as for the technical requirements of safe machine and vehicle operation.

Humidity affects how comfortable we feel in an environment. When the air has a higher humidity our bodies are less effective at perspiring. Humans perceive heat based on the rate of heat transfer from perspiration and as a result we may feel much warmer in humid spaces than arid ones of the same temperature.

In order to control the climate within buildings, HVAC systems are used to measure and control relative humidity. If the temperature of an environment is high and the relative humidity is low then water evaporation is rapid. This would cause water to be drawn from soil, fabric, wood or skin. When relative humidity approaches 100% in an environment, condensation occurs on surfaces. Over long periods of time this can cause problems with mold, decay and corrosion.

In vehicles where the environment is often sealed, condensation can become much more important to safety with problems such as misting of windshields or electrical malfunctions.

Measuring Relative Humidity (RH)

A hygrometer is an instrument used to measure relative humidity. Relative humidity is a measure of how much water the air is holding, relative to the maximum amount of water the air could possibly hold at a given temperature.

Because of the delicate design of hygrometers, it is easy for them to become innacurate (e.g. with shipping or just over time). A calibration of your hygrometer will help ensure you are measuring the relative humidity as accurately as possible. Hygrometers should be calibrated yearly.

Hygrometers are available in both digital and dial models, and both should be checked for calibration. Some dial types will have a small screw or adjusment on the back so they can be adjusted during calibration. If there is no way to adjust them, make a note of the calibration result, and then you can simply add or subtract from the actual reading to get a more accurate humidity level.

Calibration of Hygrometers

To compliment our existing UKAS calibration of temperature equipment, including mercury-in-glass thermometers, and PRT sensors, and being the only company in England to offer UKAS calibration of hydrometers with a range of 500 kg/ m3 to 2000 kg/m3, Charnwood Instrumentation are now able to carry out UKAS certification, in house, to meet your RH calibration requirements.

This enables us to offer the same excellent service and delivery times which our customers have come to expect from our temperature and density calibration laboratories.

Hygrometer Manufacturers

As distributors for Digitron and Testo, we are also able to supply your needs for new hygrometers, RH Transmitters, as well as specification thermometers and hydrometers.

Relative Humidity Instruments from Charnwood Instruments

The 2000R Range of hand-hand relative humidity instruments has been designed for the effective and reliable measurement of controlled environments. The two models 2020R and 2080R offer excellent accuracy at a budget price. Their ergonomic case design with advanced technology sensors combine to give instruments with excellent performance and long life.

The more advanced instrument 2080R includes functions such as - Dewpoint calculation, separate thermocouple input and logging and can measure humidity to 1.5% RH accuracy.

The DRT 880 is low cost,desk/wall mounted instrument with a clear digital display of humidity and temperature.

Call 01530 510615 for more information

We are happy to assist you selecting the instrument you require and have many other products available not listed here. For further help email us.

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