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How experts control air quality, check concrete frost resistance and determine whether building materials comply with fire safety requirements – in the mos.ru report.

Smash bricks to dust in a special press, spin tiles in a centrifuge with metal balls or freeze concrete. Building materials that are used in the construction of new buildings undergo such difficult tests. renovation program… Specialists Center for Expertise, Research and Testing in Construction(GBU “CEIIS”) make sure that capital contractors use only high-quality and safe materials. The testing laboratory center CEIIS includes four laboratories, in which more than three thousand tests and measurements are carried out during the year.

Earth, water and air

Moscow strictly monitors safety at construction sites. At the same time, regulatory documents not only determine the safety requirements for the construction work itself and the materials used, but also apply to everything that surrounds the new building. The air that the new settlers will breathe and the soil around the building is checked for a number of indicators. This is done by the laboratory of sanitary-epidemiological and radiation control.

Samples “from the fields” are taken by the Department of Sanitary-Ecological and Radiation Control. All samples are encrypted with a special code. The principle of maximum anonymity operates in all laboratories – no employee knows from which facility the materials for testing come from, and even who took the sample.

The task of the specialists is to identify and prevent violations at all capital projects under construction in the capital, including new buildings erected under the renovation program.

“In the laboratory of sanitary-epidemiological and radiation control, we check the quality of drinking water supplied to residential buildings, including construction under the renovation program. We control how the installed water supply system affects the water quality. The next object of control is the soil that is used for landscaping. We check it for the content of heavy metals, petroleum products and benzopyrene. We also measure the concentration of harmful substances in the air with the help of special devices – gas chromatographs, spectrometers and other high-precision devices, ”said Maxim Rivanenko, head of the testing laboratory center of the State Institution“ CEIIS ”.

All samples must comply with the sanitary and epidemiological indicators prescribed in the regulatory documents. So, even the air from the construction site of the house is checked for the presence of substances that are released during the operation of equipment: nitrogen oxides, methane, carbon dioxide, dust. When buildings are commissioned, they also examine the air inside the premises, so that there is no excess of harmful substances such as ammonia, phenol, formaldehyde (they can be released from building materials).

Mosgosstroynadzor at all stages of construction controls the compliance of buildings with radiation safety standards.

“We determine the density of radon flux from the surface of the earth – it is a natural radioactive gas, samples of which are taken around the perimeter of a house under construction. We also monitor natural radionuclides in building materials – tiles, crushed stone, sand. Nevertheless, during the four years that I have been working here, no radioactive building materials have ever been brought in, ”said Lyudmila Mikhalenko, head of the laboratory.

Test of endurance

In order for the houses to stand for a long time, building materials must be checked for strength and durability. In the laboratory for testing building materials and structures, ceramic tiles and bricks are examined every day – this is a test for tensile strength. The object is placed in a special press that measures the maximum load. For example, a building brick must withstand a load of 100 kilograms or more per square centimeter.

Facade tiles are additionally checked for wear resistance. For this, an aggressive environment is simulated in a centrifuge. Steel balls of different diameters, grinding grain, water and, of course, tiles are placed inside the device. The number of revolutions is set and the rotation begins, and then experts assess the damage caused to the facing material.

If the sample does not pass the test, then the test results are sent to Mosgosstroynadzor, Which makes a decision on bringing to administrative responsibility, issues an order to eliminate violations with ensuring control over its implementation.

The fire testing laboratory is responsible for checking building materials for compliance with fire safety indicators. Combustion is fully controlled in professional ovens, and experts closely monitor fire safety.

According to Maxim Rivanenko, all materials that have mandatory requirements related to fire safety are tested in the laboratory. If the material is to be non-combustible, but during testing it burns and sustains combustion, then it is considered combustible and is prohibited from use on site.

“Tests are carried out here in terms of flammability, combustibility, flame spread and smoke production coefficient,” said the head of the test laboratory center. “We are testing a very large list of building materials: linoleum, paint, laminate, as well as facade coating – it must also be non-combustible.”

For example, flooring samples are tested for three indicators: flammability, flame spread and smoke production coefficient.

Foundation of checks

Perhaps the main structural unit in terms of the number of types and volume of tests is the laboratory for testing building materials and structures. It is here that concrete and reinforcing steel are checked – the main building materials of every new building that is being built in Moscow.

The quality of reinforcing steel is assessed using modern equipment on a digital platform – a special tensile testing machine, which was made by the masters of the domestic plant. Its main feature is that in one cycle the press can accomplish what was previously done in the course of several tests. Moreover, the built-in sensor sends information to the computer in real time – the operator immediately sees all the indicators on the screen. During the test, the reinforcement is loaded to determine how it deforms and at what point the bar breaks.

Concrete is tested in the laboratory in much the same way as tiles or bricks – for tensile strength. In addition, it is checked for water absorption and abrasion – these main parameters determine the quality of the material.

Another important parameter of concrete, especially in our country, is frost resistance. Cold affects any material, without exaggeration, destructively. Upon freezing, the absorbed moisture becomes ice, increases in volume by 1.4 times, expansion, deformation of the material from the inside occurs. This process can be easily followed on the example of asphalt, when a small crack after winter can turn into a hole.

Rauf Yusifov, head of the laboratory for testing building materials and structures, notes that unique equipment is used to determine frost resistance – a volumetric differential dilatometer.

“Only we have such a device. If the frost resistance index of concrete is 200, then it will withstand 200 defrost-freeze cycles without loss of characteristics. Our device allows us to reduce the testing process to seven days: we put concrete samples in containers, fill them with kerosene and put them in the freezer, where we cool them down to minus 16 degrees. At the moment when the same explosive (deformation) changes occur, the sensors transmit the readings directly to the computer via Wi-Fi, ”the head of the laboratory emphasized.

The process of checking each building material in the laboratories of the Expertise Center, as well as the norms and methods for calculating the results, is clearly spelled out in GOST. For everything, there are algorithms: how many times to test, at what temperature and even at what humidity.

It is also important that each employee of the center is a high-class professional, and the average length of service of a laboratory employee is 16 years. It is the synthesis of modern technologies and human experience that is the main guarantee of quality that future residents of Moscow new buildings receive from the specialists of the testing laboratory center.

EDITOR’S NOTE: This article is a translation. Apologies should the grammar and or sentence structure not be perfect.

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