How long is the service life, and when is verification of hygrometers necessary?

Hygrometers are essential tools for assessing the moisture content of concrete, which is a critical component in defining its durability and quality. In order to preserve the strength and durability of the concrete structure, these tools assist experts in keeping an eye on and sustaining the ideal conditions for curing and setting. Hygrometers must, however, be regularly checked to guarantee their accuracy and dependability, just like any other tool.

A hygrometer’s performance may deteriorate with time, producing readings that are off. Dust buildup, mechanical wear, or calibration changes are a few possible causes of this. To keep these instruments precise and guarantee that the data they provide is accurate, regular verification is necessary. However, how frequently should this verification take place, and what indicators should be looked for?

This article will examine the average hygrometer’s service life and go over the significance of prompt verification. By knowing when and why to check your hygrometers, you can prevent future problems and make sure your concrete projects are long-lasting. Let’s get specific and discover how to maintain the best possible condition for your hygrometers.

Here is the article’s one-paragraph main thesis statement for the website "All about concrete": It is essential to comprehend the hygrometer’s service life and when to confirm its accuracy in order to maintain ideal conditions during the construction of concrete. These tools detect humidity, which has a big impact on the strength and longevity of concrete constructions. Hygrometers can become imprecise with time, producing readings that are off. As a result, frequent verification is necessary to guarantee accurate measurements, avoid expensive errors, and increase the longevity of concrete projects. This post will discuss the typical lifespan of hygrometers, warning indicators that they should be checked, and best practices for preserving their accuracy.

Period of validity and operation

Every hygrometer experiences physical wear and tear after a certain amount of use. The following time intervals represent the shelf life or service life of hygrometers, depending on the type of equipment:

• Modern electronic hygrometer – from 5 years and more, premium products – from 7 to 10 years.
• Laboratory psychrometric hygrometer – from 8 years and more, subject to constant humidification of the bath with a wet thermometer.
• Hair or film hygrometers – at least 5 years, after which the film or nylon thread must be replaced.
• Resistance, thermistor, electrolytic, ceramic hygrometers – from 10 years or more, with proper maintenance.
• Optical and condensation devices – from 12 to 15 years, subject to replacement of the LED element and cleaning of the mirror plates.

Every hygrometer that comes from a legally recognized manufacturer or brand that is sold on the market is accompanied by a quality passport that details not only the product’s primary technical specifications but also its estimated service life, the time between subsequent inspections and maintenance, and the availability of sensors, actuators, electronic modules, and other functional components.

Time for write-off

Hygrometers are susceptible to write-off when physical wear and tear occurs because major repairs will be more expensive than buying new equipment. Generally speaking, write-offs are applicable to this metal equipment under the following forced situations:

• When physical wear and tear occurs.
• In case of complete or partial destruction of the device due to mechanical or other damage.
• In case of a change in the place of operation of the equipment by moving it to a room or other environment with different temperature and humidity parameters that do not meet the boundary conditions specified in the quality passport of this hygrometer.
• When it is impossible to perform further calibration of the device, when verification always shows a deviation that differs from the reference or permissible values.
• If the repair of metrological equipment exceeds its normal or residual value.
• Upon expiration of the service life recommended by the hygrometer manufacturer – for professional laboratory equipment.
• If the lease agreement or other official document provides for the end of the device"s operation due to the need to replace it with a newer metrological device.
• If the requirements of the standards applicable to testing laboratories become more stringent, which does not allow the use of the equipment for commercial or scientific research purposes.
• In the event of other planned or emergency situations, when normal further operation of the device is no longer possible due to a number of direct or indirect objective reasons.

The user will no longer be able to obtain a guaranteed accurate result if the metrological equipment of the category in question is used after physical wear and tear and the end of the recommended service life. This will cause problems when adjusting the room’s climate or disruption of technological processes.

Reasons

Hygrometers are write-offable for the following objective reasons when they reach wear and tear or the end of their service life:

• Failure of the device settings without the possibility of their restoration.
• Equipment obsolescence.
• Harmful influence of an aggressive environment – corrosion of metal, delamination of wooden parts, bending of the supporting frame, clouding of glass, oxidation of electrical sensors and other malfunctions.
• Non-compliance of an obsolete device with current applicable standards.
• Physical wear of the hygrometer or its main functional parts.
• Failure of the device, which entails unreasonably expensive repairs.
• Mechanical damage that led to the failure of the device, or complete loss of operational properties.
• Other situations, upon the occurrence of which further operation of the metrological equipment is impossible.

If the hygrometer was previously purchased from an authorized dealer of the brand, you are under no need to discard the equipment when writing it off. In such cases, the user typically decommissions the device and gives it to the supplier at a minimum residual value. A new hygrometer is then purchased at a substantial discount.

What is it and how is it different from calibration?

Hygrometer and other metrological equipment service maintenance encompasses not only major repairs and consumable replacements but also the following concepts:

• Verification of a hygrometer is a periodic mandatory preventive operation, which consists of comparing the current results of measuring the relative humidity of the air in the operating space with the readings of a reference device. Based on the verification results, it is determined whether the equipment requires calibration, and the actual error is calculated, which is subsequently compared with the permissible factory errors specified in the quality passport.
• Calibration of the hygrometer – is assigned and carried out if the device has not passed verification, that is, the measurement error is outside the permissible values. Calibration consists of forced adjustment of the device indicator readings until reference values ​​are reached, followed by recording of these results.

Periodic verification is recommended for preventative purposes, and calibration should only be used when diagnostics and verification reveal a malfunction or failure of settings.

Purposes of the procedure

The purpose of hygrometer verification, regardless of category, is to accomplish the following useful objectives:

• Timely identification of deviations and errors in measurements that go beyond the permissible values ​​declared in the factory passport.
• Diagnostics of the device in order to determine the need for its scheduled or urgent calibration.
• Checking the correctness of the results of measurements of climatic and temperature-humidity parameters indoors or outdoors.
• Checking the compliance of the settings on the device indicator with the requirements for the operating space.
• Suspicion of a malfunction of metrological equipment after conducting a control measurement of humidity in the room.
• Repeated verification of the correctness of the hygrometer calibration after forced setting of reference settings.

The user or the testing laboratory will not be able to renew state-issued certificates if professional hygrometers are verified, which severely restricts the devices’ range of use and prevents them from producing profits from their use.

Frequency

According to the quality certificate that comes with each model, the frequency of hygrometer verification must match the inter-verification interval, or the amount of time after which control operations must be performed regardless of whether the settings are correct.

Our ability to operate equipment and carry out official reports based on expert actions’ outcomes is unrestricted thanks to these actions.

Hygrometer verification typically occurs at least during the following time frames:

• Household appliances intended for home use – once every 36 months.
• Semi-professional equipment used in specialized public spaces – medical centers, warehouses, industrial buildings – at least once every 24 months.
• Professional hygrometers installed in rooms with special requirements, or in specialized laboratories, expert organizations whose activities include detailed air analysis – at least once every 12 months.
• Regardless of the above-mentioned standard periods, in accordance with the requirements of GOST R 8.757-2011, each organization can have internal regulations and assign its own, stricter verification periods for hygrometers, for example, once every 3 or 6 months, in order to initially remove responsibility for transmitting incorrect readings.

Many authorized dealers often remove metrological equipment from warranty service in the absence of hygrometer verification and the entry of pertinent information in service books. If the device fails, the owner may incur significant expenses.

Where is it carried out?

Hygrometer verification can be done in the following locations, based on the type of device, its intended use, and other factors:

• For household appliances, verification is allowed at home, in the presence of a similar reference break, or, if possible, using folk methods.
• For semi-professional metrological equipment, verification is allowed in authorized service centers of dealers related to manufacturers, having the appropriate equipment and making a note in the service book of the owner of the device.
• For professional laboratory equipment, periodic mandatory verification is permitted only in specialized organizations and certification centers that have the authority to issue a state verification certificate.

It is advised that if the company performs professional scientific or research activities and any work operations involve the use of hygrometers, the verification of those measurements should only be done in specialized centers accredited by the state. This ensures that the measurement results will be accepted by any supervisory authorities.

How to check correctly?

Depending on how they are designed and intended to be used, different hygrometers must meet specific requirements in order to be checked. Additionally, all of the steps in the following process maps must be consistently followed:

• The hygrometer being tested must be installed strictly in the center of the premises, at least 3 m from the nearest window or door openings, ventilation outlets, at a height of 1.5 to 2.0 m above the floor.
• The easiest way to check a household hygrometer is to check the accuracy of its settings using reference equipment with similar characteristics. Both devices are installed in close proximity to each other, after which the readings on the hygrometer to be verified are determined and compared with the second device.
• The second verification method, which is suitable for condensation or psychrometric hygrometers, is to wrap it in a damp cloth. In a fully functional and adjusted device, the humidity indicator will be exactly 95%.
• To determine a more accurate error and deviations, you should prepare a bath with a warm saline solution of at least 10% concentration, followed by cooling, filtering and installing the hygrometer strictly above the liquid mirror. After covering the entire structure with an impermeable cap, after 24 hours, the scale on the indicator should show 75% humidity.
• To check laboratory equipment – electrolytic, thermistor, optical, hair or film hygrometers, you will need a special gas generator, namely, nitrogen oxide, which ensures the determination of the most accurate error.
• When testing any hygrometer in specialized certification centers, professionals use reference universal devices that provide comparison of indicators for all types of such metrological devices.
• For electrolytic or resistive hygrometers, it is also necessary to check the insulation resistance of the conductive parts, which is performed with a multimeter when the cables are energized. In case of detection of weak points or breakdowns, in addition to calibration, it will be necessary to restore the insulation, since current leakage does not allow accurate calculation of the measured values.
• When using electrolytic hygrometers, it is necessary to include a voltage stabilizer in the network so that an alternating current of 220 V with an industrial frequency of 50 Hz is provided.
• The temperature of the enclosing environment during verification should be between 18 ° C and 25 ° C.
• The atmospheric air pressure in the room where the verification is carried out should be from 85 to 105 kPa.
• Relative humidity, regardless of the category of equipment subject to verification, should be from 35% to 80%, since higher or lower values ​​will not allow obtaining an exact deviation from the standard.

Hygrometers that have had technological procedures breached during verification may not only provide inaccurate readings or measurements, but they may also malfunction quickly and become unusable in normal mode.

What comes after?

Following verification, the user receives the following kinds of documents, based on where this control procedure is located:

• In the case of self-checking household appliances, at home, the user does not receive any documents, but he can always independently keep a log of the control measurements and calibrations carried out, as well as calculate the error after checking the hygrometer readings with the quality passport of the commodity unit.
• If the hygrometer is verified in authorized serial centers belonging to the distributors of a specific brand of metrological equipment, the user receives a note in the service book about the completion of maintenance. In addition, the consumer will have an agreement on carrying out control measures in strict accordance with current regulations, as well as a payment document confirming payment for this service. In some cases, the company that carried out the verification may provide an internal certificate and an additional warranty card.
• If verification is carried out in specialized testing laboratories accredited by state supervisory authorities, then the applicant will receive an official certificate of the established form with a seal. This will indicate the possibility of using this metrological device to obtain accurate indicators that will be quoted in any government agencies.

In addition to receiving a certificate of the subsequent verification when servicing hygrometers in service centers run by official brand dealers, the customer also receives a stamp in the warranty book indicating that the metrological equipment is fully serviceable and may potentially operate normally.

Prices for services

Hygrometer verification is a required preventive procedure, but even so, it cannot be performed for free because service maintenance is frequently not covered by the equipment’s purchase price.

In this regard, the device owner must pay the following amounts for verification when contacting authorized centers of official dealers of the brand or in special testing laboratories:

• Simple verification of a psychrometric or electronic hygrometer, after the inter-verification period – from 300 to 500 rubles.
• Verification of an electrolytic resistance or thermistor hygrometer – from 700 – 800 rubles.
• Verification of professional optical or condensation hygrometers – from 800 – 1000 rubles.
• Calibration of mechanical metrology equipment – from 700 – 1000 rubles.
• Calibration of an electronic hygrometer with an LCD display – from 300 – 400 rubles.
• Minor repairs and casing of hygrometers – from 700 – 900 rubles., depending on the set of planned operations and the cost of spare parts.

The amounts mentioned above may differ slightly based on the verification location, the service center’s geographic area, whether a client visit by an expert is required, and the expert company’s or certification center’s internal marketing policies.

Why is it important to carry out on time?

Hygrometer verification is the most crucial step in their operation and is required for the following reasons:

• Ensuring normal operation of the hygrometer, correct measurements of relative humidity parameters indoors or outdoors.
• Verification is often combined with service maintenance and preventive maintenance of the main parts of the equipment, which allows to significantly extend the service life of the hygrometer.
• Timely detection of unacceptable deviations, which ensures the ability to maintain the required temperature and humidity conditions in the room or other operating space.
• The ability to obtain an official verification certificate of the state standard.
• The ability to use metrological or laboratory high-precision equipment for commercial detailing.
• Fulfillment of the requirements of regulatory documentation in force in our country.
• Ensuring the preservation of the warranty for the device, as well as free repairs, in the event of failure of the hygrometer through no fault of the user.

Even if the overall deviation is within the GOST-permissible bounds, it is still necessary to routinely calibrate the device in addition to verifying its accuracy.

The highest measurement accuracy is ensured by a calibrated device, which is crucial for use in pharmaceutical, medical, and certain industrial buildings with stricter humidity and temperature regulations.

Useful video

We advise viewing the following video on the subject of the article:

Hygrometer Type	Service Life	Verification Frequency
Mechanical Hygrometer	5-10 years	Every 1-2 years
Digital Hygrometer	5-7 years	Every 1-2 years
Hair Hygrometer	5-8 years	Every 1-2 years
Capacitive Hygrometer	5-10 years	Every 1-2 years

The quality and longevity of concrete structures can be greatly impacted by inaccurate humidity measurements, which is why it is imperative to regularly verify hygrometers. Hygrometer accuracy can decrease over time for a number of reasons, including environmental factors and sensor deterioration. You can keep your confidence in your readings and make sure your projects adhere to the required standards by regularly checking these instruments.

A hygrometer’s service life is contingent upon its kind, application, and upkeep. Even the most resilient gadgets will eventually need to be calibrated and replaced, though. Both the hygrometers and the concrete structures they assist in monitoring can have longer lifespans if you monitor the performance of your equipment and schedule routine verification.

Ultimately, timely verification and appropriate maintenance are the keys to a hygrometer that is dependable and long-lasting. You can make sure that your concrete projects are long-lasting and uphold the highest standards of quality and safety by being watchful and proactive. Keep in mind that a small investment in instrument maintenance can prevent major problems later on.

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