A device showing air humidity. A hygrometer is a device for measuring air humidity. Absolute and relative humidity

(from Greek words hygros – wet and metreo – measuring).

As the temperature decreases, the relative humidity increases. At a certain temperature, called the dew point, water vapor becomes saturated. This means that there is as much water vapor as possible in the air. Relative air humidity is 100%. A further decrease in temperature leads to the fact that the resulting excess water vapor begins to condense in the form of droplets of dew or fog.

To determine relative air humidity, you can artificially lower the air temperature in a limited area to the dew point. Absolute humidity and, accordingly, the water vapor pressure will remain unchanged. By comparing the water vapor pressure at the dew point with the saturated vapor pressure that could be at the temperature we are interested in, we will thereby find the relative humidity of the air.

Rapid cooling can be achieved by intense evaporation of some volatile liquid.

A condensation hygrometer consists of a metal box with two holes. Ether is poured into the box. Using a rubber bulb, air is pumped through the box. The ether evaporates very quickly, the temperature of the box and the air near it decreases, and the relative humidity increases. At a certain temperature, which is measured by a thermometer inserted into the hole of the device, the surface of the box is covered with tiny droplets of dew. In order to more accurately record the moment when dew appears on the surface of the dew box, this surface is polished to a mirror finish, and a polished metal ring is placed next to the box for control.

Values ​​of pressure and density of saturated steam at different temperatures can be found in reference books. Below is a fragment of the corresponding table.

Table 1. Pressure and density of saturated steam at different temperatures

Let, for example, measurements be carried out at an ambient temperature of 20 °C.

The pressure of saturated water vapor at this temperature is 2.33 kPa.

Box condensation hygrometer covered with dew drops at a temperature of 5 ° C.

This temperature corresponds to a saturated water vapor pressure of 0.88 kPa.

Relative humidity

Psychrometer (from the Greek words: psychros - cold and metreo - measure) - a device for determining air humidity and temperature.

A psychrometer consists of two identical thermometers. A can of liquid from one of the thermometers is wrapped in a cloth, the end of which is dipped into a cup of water. Thanks to this, the cloth always remains damp. As the water evaporates, the cloth and the canister cool, causing the wet-bulb readings to be lower than the dry-bulb readings. Knowing the difference between thermometer readings and dry thermometer readings, you can use special psychrometric tables to determine the relative humidity of the air. If the air is extremely saturated with water vapor and its relative humidity is 100%, thermometers will give the same readings.

For example, let the dry thermometer show a temperature of 24 °C, and the wet thermometer show 21 °C. The difference between the dry and wet thermometer readings is 3 °C. At the intersection of the corresponding row and column, we find that the relative humidity is 77%.

Hair hygrometer.

Action hair hygrometer based on the property of defatted human hair and some organic films to change their length depending on the relative humidity of the air. If a hair or film is connected through a transmission mechanism to a movable pointer mounted on an axis and the scale is calibrated, then using such a device you can directly measure the relative humidity of the air.

Important indicators that determine the microclimate of an apartment, house or any other room include temperature and moisture content in the air. And if the temperature can be approximately guessed by sensations, then for the second parameter you will need a special device to determine air humidity.

If there is too much vapor in the air or, conversely, not enough, this greatly affects the immune system. To avoid health problems, special devices are used to measure humidity.

In this video you will learn what a psychrometer is

There are two types of humidity:

1. Absolute. Shows the amount of water in g/mᶟ.
2. Relative. To calculate its value, you need to divide the current humidity by the maximum possible, then multiply the resulting value by 100. Relative humidity is measured as a percentage. To obtain exact value, you need a device to determine the relative humidity of the air.

Lack and excess of moisture

For people, animals, plants and even some materials, excess moisture is just as destructive as its lack. If there is a lot of moisture in the room, then the first thing you can notice is on the glass of the window, which begins to sweat a lot. From such excess moisture, the air and things acquire a damp smell, and mold forms on the walls. It provokes various allergic reactions that reduce the body's immune defense.

Lack of moisture can lead to dehydration, as sweating increases indoors. In addition, the amount of dust in the air sharply increases, and this can cause allergies.

Measuring instruments

The accuracy of the readings depends on which device is used to determine air humidity. Exist different types devices:

1. Hygrometer. You can most often find a hygrometer on store shelves. electronic type, it is ideal for simple monitoring and is inexpensive. But there is a significant drawback - low accuracy of readings; on average, its error can reach 20%. It is considered more accurate mechanical device, but it will cost several times more. You can find hair and film hygrometers. The peculiarity of these two varieties is that both will give accurate readings only when low temperatures, and in the hot season you shouldn’t expect accuracy from them.
2. Psychrometer. According to experts, this particular device is considered accurate. The operating principle of the device is as follows: the psychrometer has two thermometers and a special table. On one of the thermometers there is a can of liquid, which should be wrapped in a rag. One end of the rag should always be in a cup of water. To obtain the result, the difference between these thermometers is taken for calculation and the relative humidity is determined using a psychrometric table. The psychrometer is very convenient to use, as it allows you to monitor two indicators in a room at the same time.

A thermometer can measure air humidity

Of the two types, each person must choose for himself which device is right for him. Perhaps someone will choose a more accurate one, while others will choose a device that is more convenient to use.

To make a room comfortable, it needs optimal microclimate. A device for measuring air humidity will help maintain the desired level. This is very important for creating normal conditions in the living space, since this indicator affects the health and well-being of people.

Lack of humidity in the home can be hazardous to health

Humidity and well-being

The level of humidity is determined by the content of water vapor in the air. It can be absolute and relative. Our body is almost 70% water. For supporting normal condition everyone's life important processes The body must consume at least 2 liters of clean water daily.

When a person is for a long time in a room with dry air, this negatively affects the condition of the skin, it ages quickly. During breathing, the lungs release air whose humidity is 100%. When you swallow dried food, it is moistened by fluids inside the body.

You will see how to determine air humidity at home in this video:

A long period in a room with dry air leads to drying of the mucous membranes. For this reason, people often experience the following symptoms:

• dry mouth and dry lips;
• nasal congestion;
• sniffling;
• slight cough;
• snoring at night.

Excess moisture also has a detrimental effect on living organisms. Almost all objects in the living space become covered with drops and acquire an unpleasant damp smell. Such clothes and bed linen It's always unpleasant to use. Food also spoils due to excessive moisture, after which it is dangerous to consume it. All structures are gradually covered with mold, the spores of which spread everywhere. This often causes allergies and weakens immunity. There are other more dangerous diseases if living conditions do not improve.

Excess moisture also has a detrimental effect on human health, causing the appearance of mold and mildew.

Measuring devices

Today, many different devices have been invented that can measure air humidity levels. Such devices can be special or improvised. They help determine these important indicators. At home they are used very simple methods measuring the degree of moisture. An ordinary thermometer or a glass of water or other items are suitable for this purpose.

I use various instruments to measure the humidity level in a room.

The most common meters are called hygrometers and psychrometers. They perform the same function, but differ in operating principle.

The hygrometer is not able to show accurate data, since changes in water vapor parameters are insignificant. However, such a device is quite suitable for home use. If you want to have more accurate measurements in your apartment, then it is better to check with a psychrometer.

Application of a hygrometer

This device records changes in the decrease or increase in moisture vapor in the air. These are quite complex devices. They come in several types:

• hair;
• condensation;
• electrolytic;
• weight;
• ceramic.

A striking example is the hair device. It uses natural, oil-free human hair to measure air humidity. It changes its length as the percentage of moisture changes and allows you to obtain data in the range from 30 to 100%. However, it has significant drawback- large measurement error. The advantages include fast reaction to changes and a high degree of sensitivity.

Such a device for measuring relative air humidity is often used in residential rooms. Externally, it is a beautiful device, so it sometimes serves as an interior decoration.

A film-type device is widely used. To determine the moisture level, it uses an element in the form of an organic film. Other types of hygrometer are rarely used at home because they are too expensive and difficult to use.

Now it is possible to purchase an electronic model. The digital device must be connected to an electrical outlet or use batteries. The display shows temperature and time every 10−20 seconds. The reading error is about 6%.

Psychrometric method

IN living conditions The most commonly used device is a device that determines air humidity, called a psychrometer. Unlike hygrometers, it does not allow errors in measurements. Used in the device itself simple type two sensors:

• dry;
• wet.

The evaporation of water causes the wet sensor to cool, and the dry element at this time records the temperature readings in the space. All data on changes in readings can be observed on a special microprocessor device. A psychrometer - a device for determining indoor air humidity - has its own tables.

The most commonly used device at home is a psychrometer.

To take data, you need to record the readings of the dry thermometer and then subtract the degrees of the wet thermometer from it. Using the difference, you can determine the value on the horizontal scale, which will correspond to the moisture level. Device for household needs There are several types:

• stationary;
• aspiration;
• remote.

These are simple, reliable devices that allow you to obtain the most accurate data on the level of water vapor in a residential building. However, they require constant monitoring for the presence of moisture in the wet sensor. It allows you to monitor the temperature scale of the air and the humidity of the room.

Simple ways

To determine the level of air humidity at home, it is not necessary to buy special devices. You can use improvised means that are always available. They will not give exact indicators, but with their help it will be known how humid, dry or normal it is in the living space.

The air humidity in the room can also be measured using improvised means.

One of the most simple ways- Fill a glass with water and put it in the refrigerator. The liquid must be cooled to +3 o C and then placed on the table in the room. Within 5 minutes you need to observe the condensation on the walls of the vessel. Foggy glass indicates normal levels of water vapor in the air. If the walls are dry, this is a lack of moisture, and when the drops flow down, then there is high humidity in the room.

You can also determine moisture levels in the air based on the state of the flowers. They react painfully to dryness, so the tips of the leaves begin to dry out. However, this method is only suitable for those indoor plants who love to be sprayed.

Another proven method is a lit candle. When the flame rises during combustion, the level is normal. If it rises in different directions with a crimson halo, then there is too much water vapor.

The optimal degree of relative humidity in the room should not exceed 30−60%. The exception is regions where natural humidity is higher and amounts to 75%. Being aware of the level of moisture in your living space will help you avoid many troubles related to the health of the entire family.

Air humidity is one of the main indicators favorable microclimate in the apartment. This value determined, as a percentage of the number of water molecules in a cubic meter of air at certain temperature, to their maximum quantity in saturated steam under the same conditions.

Air humidity in a living room according to GOST 30494-2011 should not fall below 30% V winter period and exceed 65% in summer.

Support the humidity level in the apartment is optimal level necessary to create favorable conditions for human life. Excessive or insufficient humidity air may reduce immunity, worsen heat exchange and lead to acute and chronic diseases. Carry out regular control relative humidity in residential areas is helped by measuring devices.

In contact with

Classmates

Measuring humidity with special instruments

When choosing a device, you should note per size, permissible temperatures, at which measurements can be made, limits permissible errors, methods of fastening or installation.

Hygrometers

According to indications "dry" thermometer and temperature difference find the value relative humidity.

Weight hygrometer- a system of u-shaped tubes with adsorbent material through which air is pumped. Based on the change in the mass of the material, the moisture content in the material is determined. known volume air in g/m3.

Hair And film A hygrometer is used to determine the relative humidity in the room. Natural hair or organic film have the property to react to changes in humidity. The arrow of the sensitive device reacts to these changes and indicates on the scale exact meaning.

Electronic home hygroscopes

Condensation The hygroscope measures the temperature of a cooled mirror when it appears on its surface. condensate, and compares it with the ambient temperature.

Electronic hygrometers are multifunctional and mobility. You can install them anywhere in the room, modern design will not damage the body general interior premises.

Important: Many models of electronic hygrometers are equipped with a memory function and can record changes in readings over a certain period of time.

Mercury thermometer

• Medical mercury thermometer;
• Thin cloth;
• Water;
• Stopwatch or watch;
• Psychrometric table (can be found on the Internet).

Measurement temperature in the room is carried out at first dry bulb thermometer, then wrap the mercury tip wet cloth and through 10 minutes they take a second measurement. Calculate difference between the readings and find the relative humidity value using the reference table.

In a vertical column the table shows dry bulb readings, and the top horizontal line the value of the temperature difference. In the cell at the intersection of the lines of two readings one finds percentage indicator of humidity in the room.

Self-measurement of air humidity

If the concentration of water vapor in the room approaches the concentration of moisture in saturated vapor, then evaporation will difficult. This sign indicates on increased moisture content in room.

To conduct an experiment (determine humidity) necessary:

• Fill a glass vessel(glass, jar, bottle) water;
• Place a container of water in the refrigerator for 2-3 hours;
• Measure the water temperature, it should be no higher than 50C;
• Place control vessel far away from heating devices;
• Time it monitoring condensate evaporation ( 5-10 minutes).

  When dry indoor air, condensation on the walls of the vessel will evaporate after a specified period of time. If the glass remains wet, then the room has an optimal level of humidity. On increased The moisture content in the room air is indicated by large drops of water that collect in streams and flow down the smooth surface vessel.

  How to increase humidity in an apartment?

  

  As you know, dry air harmful for human health. To improve microclimate in the apartment - can be set household humidifier air. Modern devices According to the method of preparing and spraying water, there are nozzles, steam and ultrasonic.

  Nozzle or traditional humidifier sprays water using a built-in fan. Its advantage is self-regulation evaporation rate.

  Steam appliance works on the principle electric kettle, the steam temperature reaches 600С. The most popular model is ultrasonic humidifier, which sprays water vapor in the form of fog. Quiet, compact and safe device suitable for any room.

  For maintaining humidity in an apartment at an optimal level it is necessary to fully ventilate all rooms, separate houseplants and water and spray them regularly, install a large aquarium.

  In winter, when the air in the rooms becomes dry, you can place vases with water on flat surfaces, and hang humidifiers in the form of small containers.

  What to do if the apartment is too humid?

  

  Excess moisture in the apartment may cause to the formation of mold and mildew on walls and furniture. The presence of spores of toxic microorganisms in the ambient air negatively affects human health.

  Therefore, it is necessary to take in time:

  • Place on window sills and sanitary premises moisture absorbers;
  • Check the draft in the exhaust ducts of the bathroom, bathroom and kitchen;
  • Increase the area of ​​heating devices;
  • Provide air conditioning in optimal mode;
  • Turn on while cooking.

  To reduce the humidity level in the apartment, you can use a household dehumidifier air. Inside the body of such a device there is a cooled plate on which moisture condenses. After heating, the air enters the room again. Performance varies among different models from 12 to 300 l/day.

  Advice: To select a dehumidifier based on performance, you need to multiply the area of ​​the room by a factor of 0.7.

  Excessive or insufficient moisture content in the air of a residential area adversely affects human well-being and health. Regular control relative air humidity using one of the types of household hygrometers allows you to maintain the microclimate in the apartment at an optimal level.

  For creating comfortable conditions It is necessary to carry out preventive and emergency measures to humidify or dehumidify the air.

  From this video You will learn how and with what to measure the humidity level in an apartment:
  

In contact with

See inaccuracies, incomplete or incorrect information? Do you know how to make an article better?

Would you like to suggest photos on the topic for publication?

Please help us make the site better! Leave a message and your contacts in the comments - we will contact you and together we will make the publication better!

The cause of relapses of allergic and respiratory diseases can be the indoor microclimate: temperature, absolute and relative humidity. Normal values these parameters are created favorable conditions for a person to live in an apartment or private house. But how is air humidity measured? The answer is simple: a hygrometer or psychrometer.

Before purchasing a device, you should learn about its advantages and disadvantages.

One of undoubted advantages The device for determining the moisture content in airspace is easy to operate.

Optimal values

Humidity in an apartment is the degree of vapor saturation in the air. It is measured as a percentage of the actual amount of moisture to the maximum possible meaning at the same temperature. Its increased parameters are easy to determine: it appears mold in the corners of the room, a person becomes aggravated chronic diseases, immunity decreases. When indoor humidity is low, wooden furniture quickly deteriorates, and family members experience unpleasant sensations of dry mucous membranes of the nose and eyes. If there is no moisture in the surrounding space, then the dust does not settle on surfaces for a long time, but remains in the air and penetrates the bronchi and lungs.

The purpose of the room determines optimal parameters humidity. The norm is expressed as a percentage:

• living room – 50-60%;
• bedroom – 45-50%;
• children's - 50-60%;
• office – 40-45%;
• kitchen and bathroom – up to 60%.

The values ​​obtained during the measurement process are influenced by many factors - time of year, power of heating radiators, region of residence.

Experts operate with two types of humidity:

• relative;
• absolute.

The last value shows how much moisture is in a cubic meter (how the air in the room is measured). At home absolute indicator practically not used.

Humidity parameters can be determined using indoor plants. If the leaves curl and turn yellow, they are often inhabited by harmful insects, then the air in the room is very dry. When flowers appear brown spots, and the roots begin to rot, this means that there is excess water content in the surrounding space.

Relative air humidity is measured using instruments that are convenient to use by a person without special skills in working with complex devices. This parameter is quite sufficient to determine the moisture content in the surrounding space.

Types of devices

At home, measure air humidity different ways, but the most objective values ​​are obtained when using special devices: hygrometer and psychrometer.

Air humidity is measured using a hygrometer, the principle of which is based on recording variables when the concentration of water molecules in the surrounding space increases or decreases. Under such conditions, changes physical parameters(density, mass, length) structure of the material used in the measurement process and actively absorbing moisture. The results obtained will characterize the degree of saturation of the surrounding space with water vapor. Before measuring air humidity using a hygrometer, keep in mind that the values ​​will be approximate.

In specialized stores, hygrometers are presented in a wide range. They are:

• hair;
• by weight;
• condensation;
• electrolytic;
• ceramic.

For household use No special precision instrument is required. It is easy to determine relative humidity with a hygrometer, but there are also performance characteristics device.

Before measuring air humidity, you need to consider the features of using a hygrometer:

• You must always ensure that the dampening material is wet and clean;
• Do not place the device near air conditioners and radiators.

The principle of operation of a hygrometer is based on comparing the readings of a thermometer in contact with wet material and a thermometer recording values ​​in a real environment. The results are determined on a conventional graduated scale. The difference in parameters is checked against the data of the psychometric table, regardless of which device the values ​​were obtained from.

To measure air humidity using a psychrometer, you need to understand the principle of its operation. When liquid evaporates, the temperature of the surrounding space decreases. The more intense the evaporation, the cooler the air becomes, which is determined by the device. This process is influenced by a complex of factors:

• water vapor concentration;
• speed of air flow in the room.

Taking into account the temperature difference between the wet material and the air, the rate of evaporation can be determined. If the device is located near a window or fan, the obtained values ​​will not be accurate due to the circulation of flows.

Relative air humidity is measured using the following types psychrometers:

• stationary;
• remote;
• aspiration.

The latter are considered the most accurate and reliable devices. It is very easy to measure air humidity using an Assmann psychrometer - the device is equipped with a protective housing. Therefore, the obtained values ​​are not affected by air flow speed.

Handy methods

One of the informative methods by which you can determine the humidity in an apartment is observing a burning candle. In a room with a normal microclimate, its flame is strong and even. When there is excessive moisture content in the surrounding space, the candle flame fluctuates from side to side, and scarlet inclusions appear on its edge. Do not forget that air humidity is measured in this way with the windows and doors closed.

You can determine the water vapor content using a regular glass of water. After placing it in the refrigerator, you should wait about an hour. During this time, the temperature of the liquid will drop to 3-4°C. Relative air humidity is determined after removing the glass and observing the evaporation processes taking place:

• the walls of the vessel remain fogged - the moisture content is within normal limits;
• the walls are dry - low humidity air;
• condensation flows down - there is a lot of water vapor in the surrounding space.

If your laundry dries quickly in your room, you should consider purchasing a humidifier. And dampening of fabric items indicates an excess amount of moisture in the room.

It is up to the owner of the premises to decide which device to use. People who care about their health and strive to maintain all microclimate parameters within normal limits equip their apartment with real home weather station. Manufacturers have launched the production of devices equipped with a barometer, hygrometer and thermometer. Of course, such a device cannot be cheap. But all costs quickly pay off - the owners of the premises save on medicines for family members, they do not need to change wallpaper damaged by fungus and upholstered furniture.