Basic rules: how to use a hygrometer, read readings and make adjustments?

Anyone working with concrete needs to know how to use a hygrometer correctly because it helps track the material’s moisture content. To guarantee that the concrete sets properly and keeps its strength and durability over time, proper moisture control is essential. We’ll go over how to use a hygrometer, how to interpret its readings, and how to make any necessary adjustments in this article.

Let’s start by discussing how to set up your hygrometer. It’s crucial to position the device so that it can detect moisture levels accurately. Its readings may be distorted if you place it in an area with strong air movement or close to direct heat sources. After being properly positioned, give the hygrometer a few hours to adjust to the surroundings before taking any readings.

Hygrometer reading is simple, but it needs close attention to detail. The humidity level is displayed as a percentage on the dial or digital display of the majority of hygrometers. The ideal relative humidity range for concrete is usually between 40% and 60%. To keep track of any changes in moisture levels over time, carefully read the display and take regular notes on the readings.

Adjustments must be made if the readings show that the humidity is either too high or too low. If the humidity is high, you might want to use dehumidifiers or increase ventilation to get rid of the extra moisture in the air. If the humidity is low, you may need to use humidifiers or lightly mist the area with water to increase the moisture content. Maintaining the recommended range of humidity is essential to ensure proper curing of the concrete.

You can make sure that your concrete projects take advantage of ideal moisture conditions by adhering to these fundamental guidelines. Utilizing a hygrometer for routine monitoring will assist you in preserving the ideal conditions for your concrete to function at its peak. Remain alert and make necessary corrections to ensure the longevity and quality of your work.

Step	Description
1. Place the Hygrometer	Put the hygrometer in the area where you want to measure humidity. Ensure it"s away from walls and direct sunlight.
2. Wait for Stabilization	Allow the hygrometer to adjust to the environment for at least 15-30 minutes before taking a reading.
3. Read the Measurement	Check the display to see the humidity level, usually given in percentage (%).
4. Make Adjustments	If the humidity is too high, use a dehumidifier. If it"s too low, use a humidifier. Aim for a comfortable level, typically between 30% and 50%.

General principles of operation

With the help of an LCD display, modern hygrometers measure atmospheric humidity indicators automatically. Usually, the user just flips them on without giving the equipment’s working principle a second thought.

In addition, the following principles, technical processes, and physical phenomena form the basis of the metrological equipment’s operating algorithm:

• The hygrometer is based on thin glass planes, onto which a thin beam of light is directed.
• The surface of the mirror cools, and a certain amount of condensation accumulates on it.
• Depending on the amount of light and the air temperature in the room or outside, both water droplets and crystallized pieces of ice can form on the smooth surface of the mirror.
• The amount of moisture on the surface of the mirrors is measured by a special scanner, after which the readings are transmitted to the actuator.
• In the electronic unit, the program converts data on the amount of moisture into a relative indicator as a percentage, after which this value is displayed on the device screen, or, in the case of mechanical equipment, the arrow indicates the corresponding division on the scale.

Modern hygrometers with an electronic unit and LCD display are advised by experts to be purchased because they can display relative humidity values with an accuracy of 0.1% or 0.01%. This removes even the smallest measurement error, which is particularly important for facilities like warehouses, hospitals, and other establishments that have particular needs when it comes to humidity and temperature.

How to properly calibrate and verify?

Hygrometers, like any other metrological equipment, need to be periodically verified, calibrated, and adjusted. You must always follow these steps in order to perform these metrological operations.

Reference device

1. It is necessary to stock up on similar metrological equipment in advance, which shows a 100% accurate result of measuring air humidity.
2. The reference gigrometer is installed in the working position, and, upon completion of the level of water vapor in it, these indicators are recorded as the basis for verification.
3. The device under test is installed in the same place as the reference hygrometer.
4. Certain readings are displayed on the screen or on the scale of the hygrometer.
5. The values ​​of the two hygrometers are compared with each other, on the basis of which a decision is made on the need to calibrate the questionable device.

High humidity

• This method only involves identifying the faulty device, or checking its normal functionality.
• The device is wrapped in a cotton rag soaked in water and wrung out for at least 1 – 2 hours.
• The values ​​on the hygrometer should increase until 96% humidity is reached.
• When the arrow or the digital value on the screen reaches this indicator, the device stops measuring humidity.
• If the metrological equipment gives a lower value, this means that it needs to be calibrated with a reference device.

Salt

• This method allows you to reliably determine with an accuracy of 0.1% the correctness of the device readings, as well as the need for its calibration.
• Hot water is poured into a vessel with a volume of 3 or more liters, to which at least 15 – 20% of the mass fraction of table or sea salt is added.
• The liquid is thoroughly mixed until the salt is completely dissolved.
• The resulting solution is poured into another container through gauze or a sieve to filter out the remaining salt deposits.
• A simple mount for the hygrometer is constructed above the surface of the solution, directly in the container.
• The metrological device is fixed on the stand in the working position, strictly above the bath with the saline solution.
• The finished structure is covered with a bucket or other high container to ensure complete tightness of the vessel with the solution and the hygrometer itself.
• Exactly one day later, the lid over the structure is removed, after which the readings are recorded from the hygrometer screen.
• The screen or scale of the device should display readings of 75% relative humidity.
• If these values ​​are more or less than 75%, this indicates the need for calibration.

Mechanical device

1. These devices have rotary handles.
2. When the handle is pressed, the hygrometer arrow is released from the moisture analyzer drive.
3. When the handle is turned, the arrow is set in motion in either direction.
4. The hygrometer arrow is carefully set to the desired position, according to the control values ​​of the reference device.
5. Upon completion of the work, the hygrometer is re-verified, according to any of the algorithms listed above.

Electronic

• Such devices often have an automatic calibration key, pressing which leads to automatic alignment of the metrological equipment indicators to the reference values.
• In cases where automatic calibration is not provided on the device, it is usually equipped with a forced adjustment key on the front or back side.
• When pressing and blocking the key, on the control panel of the hygrometer, buttons with arrows are pressed, which regulate the indications for 1 division price in a larger or lesser side.
• When the required readings are displayed on the screen, the lock key is removed, which allows you to start the hygrometer with the already calibrated values ​​on the screen.
• After calibration, it is recommended to re-verify the device to ensure its normal operation over the next few months.

Professional hygrometers are verified and calibrated in the authorized dealers’ service centers because, upon completion of this process, an official verification certificate is granted, permitting you to use this metrological equipment for business purposes and to prepare reports that you may submit to the relevant regulatory bodies upon request.

Here are more specifics on setup and calibration.

Table of device readings

By measuring the difference between the readings of two thermometers—one dry and the other wet—classical mechanical thermometers can calculate the air’s absolute humidity. The psychometric table, which is provided below, shows all values:

Dry thermometer values, o C	Numerical difference between the values ​​of dry and wet thermometers
	0	1	2	3	4	5	6	7	8	9	10
	Values ​​of the desired parameter – relative humidity, %
12.0	100	89	78	68	57	48	38	29	20	11	—
13.0	100	89	79	69	59	49	40	31	23	14	6
14.0	100	89	79	70	60	51	42	34	25	17	9
15.0	100	90	80	71	61	52	44	36	27	20	12
16.0	100	90	81	71	62	54	46	37	30	32	15
17.0	100	90	81	72	64	55	47	39	32	24	17
18.0	100	91	82	73	65	56	49	41	34	37	20
19.0	100	91	82	74	65	58	50	43	35	29	22
20.0	100	91	83	74	66	59	51	44	37	30	24
21.0	100	91	83	75	67	60	52	46	39	32	26
22.0	100	92	83	76	68	61	54	47	40	34	28
23.0	100	92	84	76	69	61	55	48	42	36	30
24.0	100	92	84	77	69	62	56	49	43	37	31
25.0	100	92	84	77	70	63	57	50	44	38	33

These values ​​are GOST and are indicated as reference, which allows the consumer to accurately determine the relative humidity, provided that there is no modern electronic device with automatic output of ready-made indicators in the room.

Such hygrometers with a psychrometric table, as a rule, are used today only in laboratory conditions or for educational purposes.

Norms of humidity indicators

Norms of readings are reference values for relative humidity that satisfy GOST R 8.758-2011 requirements and are calculated with a hygrometer.

These indicators are recorded in a special journal and can be computed using a verified and calibrated metrological device. The results of the room survey are the basis for their calculation.

The wet and dry thermometer readings, the difference between each thermometer’s scale value, and the relative humidity in percentage are all recorded in the journal that the lab assistant put together.

The device’s serviceability and the need to modify the humidity and temperature in the room under survey are both determined by comparing the log’s values with those from the psychrometric table and the GOST standards.

Step-by-step instructions for use

Certain contemporary hygrometers can be operated without the need for specialized knowledge because the necessary indicators are automatically measured.

Professional intervention is necessary for high-precision professional and laboratory devices due to their unique characteristics and the need for strict adherence to guidelines in order to achieve precise measurement outcomes.

The comprehensive process maps for the proper operation of every class of mechanical and electronic hygrometer on the market are provided below.

Volosyanoy

1. Synthetic hair is stretched between the upper support of the device tripod and the spring of the rotary arrow.
2. The stopper is removed from the metrology equipment, which ensures free movement of the arrow.
3. As the relative humidity level in the room changes, the hair changes its length – it lengthens or shortens.
4. The spring mechanism is set in motion, and the hygrometer arrow deflects.
5. As the arrow deflects, it begins to point to the desired division on the scale located along the trajectory of the part.
6. Depending on the actual humidity in the room or outside, the hygrometer arrow points to values ​​in the range from 30% to 80%, which are subsequently recorded in the log.

Regarding the functionality of the gadget in the video:

Film

• The operating principle of such a hygrometer is similar to the previous version.
• The ultra-thin film membrane reacts to the slightest changes in humidity in the operating space, which causes the arrow of the device to also deviate from the vertical position and be fixed opposite the graduated scale.
• The film is stretched between 2 or 3 flat clamps located on the frame, after which the device is installed in the center of the room.
• The hygrometer should be left in the resting position for 2 to 6 hours.
• As the film is stretched, the arrow will deflect until it takes the final position corresponding to the actual relative humidity of the air, after which these indicators can be read and officially recorded.
• Considering that the operating principle of such a device is based on a physical change in the properties of matter, it is recommended to wait at least a day until the arrow of the metrological equipment stops completely.

Condensation, or weighing

• Condensation forms on the mirror inside the device, which reacts to the temperature indicators in the room.
• To reset the device, you need to use a rubber bulb, which cleans droplets of moisture on the mirror, ensuring that the arrow deviates to the vertical starting position.
• When installing a calibrated and zeroed hygrometer indoors, as the temperature between the mirror surface and the environment changes, condensate drops or ice crystals begin to form on the surface of the silvered mirror.
• Based on the amount of condensate formation, the device analyzes their quantity, after which the arrow begins to deviate towards a certain value, which indicates the actual relative humidity of the air.
• As in previous cases, the readings are recorded in a log, after which they are analyzed with the previous ones, which allows you to determine the need to adjust the values.

Psychrometric

1. This type of metrological equipment is described in detail above.
2. The user installs the device on the surface of the table, approximately in the center of the room, at a sufficient distance from the window.
3. The wet thermometer must be immersed in a humid environment, after filling a special flask with water at room temperature.
4. Over the course of 1–2 hours, temperature readings are established on the dry and wet thermometers.
5. As a rule, psychrometric hygrometers are manufactured in such a way that a graduated psychrometric scale is depicted on the back plate.
6. The user calculates the difference between the dry and wet thermometer readings, after which he compares this difference with the reference values ​​on the psychrometric table.
7. The obtained data are recorded in the report of the established laboratory sheet.

Electronic, or digital

• This device does not require special knowledge during its use.
• The hygrometer, which is most often manufactured in a single housing with a room thermometer, is installed on the flat surface closest to the partition next to the window.
• If necessary, a cable with an external sensor for determining the air temperature outside the window is clamped by the glass unit sash.
• The batteries are installed in the hygrometer, after which it is turned on.
• The device is saturated with air moisture for 1-2 hours, and the readings on its screen are aligned to real values.
• Some electronic/digital hygrometers have a button for recording current values ​​for the purpose of their subsequent comparison to change the climatic parameters of the air in the room.

Experts advise against buying any other type of metrological equipment for home use other than electronic metrological devices coupled with thermometers because these hygrometers don’t need complicated calculations and only need to be calibrated every three to five years because there aren’t any extremely high or low temperatures or humidity levels.

How to read the readings?

Since some hygrometer models only provide intermediate indicators of the percentage of water vapor in the room, they necessitate detailed calculations of relative humidity. Psychrometric moisture meters are one type of such gadget that shows just two thermometer readings: wet and dry.

The following straightforward formula is used to determine the relative humidity final result:

_drywet

This value is more than enough to replace it in the psychrometric table, which shows complete conformance with the determined and measured indicators of the room’s relative humidity.

How to interpret the values:

• in the left column of the table, the user can find the value of interest on the dry thermometer scale;
• in the top line – the difference between the values ​​of the dry and wet thermometers;
• at the intersection of 2 guides from the corresponding values, the desired value of relative humidity is located.

A basic interpolation between two or four values must be performed if the value falls between the indicators shown in the psychrometric table.

To do this, take the larger value and subtract the smaller one from it. Then, divide the result by the number of decimal places that separate the integers, and multiply the result by the actual figure that the thermometer displays based on the measurement results.

Difficulties and errors in measurements

The following are the most frequent mistakes and issues that novices and inexperienced users can always run into when utilizing hygrometers of various categories on their own:

1. Lack of verification or calibration of any of the devices presented on the market, regardless of its category and design – the hygrometer will give false readings that cannot be used in the future.
2. Lack of a wet bath for a psychrometric hygrometer – the device will give incorrect temperature results for a wet thermometer, which will not allow you to correctly calculate the relative humidity.
3. Physical wear of a nylon thread or polymer membrane for a hair or film hygrometer – also, the readings will not be able to reach the desired humidity level.
4. Lack of charged batteries for the electronic hygrometer – the programmable unit will return an error based on the measurement results.
5. Dust, grease deposits or other deposits on the condensation hygrometer mirror – these deposits lead to settings failure, the need for maintenance and calibration of the device.
6. Errors in calculations when determining relative humidity – before starting operation, it is recommended to write out formulas in advance to avoid the risk of using incorrect values.

Before using the hygrometer, carefully read the instructions for correct use and reading the indicators. You should also familiarize yourself with several lessons and master classes that experts frequently share with other Internet users in the public domain in order to avoid making the mistakes listed above.

The accuracy and longevity of concrete depend on the proper use of a hygrometer. Place the hygrometer in the center of the concrete surface and wait for it to stabilize in order to obtain accurate readings. To keep an eye on the moisture levels, check the readings frequently. To maintain ideal conditions for the concrete to set properly, modify your curing process if the readings are too high or too low. This easy-to-follow but essential procedure ensures that your concrete project has the strength and longevity you want by preventing problems like improper hardening or cracking.

Recommendations for long service life

Any type of hygrometer is a fairly basic metrological device that needs to be maintained on a regular basis to extend its useful life without sacrificing its ability to measure humidity parameters.

Premature physical wear and tear and early hygrometer failure can be prevented by following several crucial guidelines:

• Hygrometers must be in good working order.
• Before using the hygrometer, it is recommended to make sure that it is set up correctly.
• It is recommended to check and calibrate the equipment every 12–36 months.
• For condensation hygrometers, it is necessary to monitor the quality of the mirror surface.
• For psychrometric equipment, it is necessary to periodically fill the wet thermometer bath with water.
• Nylon thread or polymer film for hair or film hygrometers are subject to replacement when plastic deformations and sagging are achieved.
• The device should be installed only in those rooms where the air humidity exactly matches the capabilities of the equipment and the boundary conditions for measuring the percentage of water vapor, according to the quality passport of the commodity unit.

It should be remembered that the hygrometer’s construction quality plays a significant role in ensuring a long and trouble-free operational life.

In order to completely eliminate physical wear and tear, it is also advised to consider the manufacturer when making a purchase and whether a particular product of the brand has a significant number of positive reviews from happy customers posted on independent online forums.

Knowing how to use a hygrometer correctly is crucial to keeping concrete curing conditions at their ideal. You can make sure that your concrete maintains the proper moisture level, which is essential for its strength and durability, by adhering to the fundamental guidelines. Problems like cracking or incorrect curing can be avoided by routinely monitoring the hygrometer readings and making the required adjustments.

Keep in mind to properly calibrate your hygrometer and position it so that it can provide you with the most accurate readings. Steer clear of places with strong sunlight or extremely cold temperatures as these can distort your findings. Maintaining a record of your readings and modifications will enable you to identify patterns and make wise choices for upcoming tasks.

By using these techniques on a regular basis, you can improve the caliber of your concrete work and make it more durable. Learning how to use a hygrometer effectively will greatly increase the success of your concrete projects, regardless of your level of experience or interest in do-it-yourself projects. If you remain watchful and continue to learn, your concrete will be successful.

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