RU2295123C1 - Method for diagnostics of technical condition of metallic engineering structures and communications of a building - Google Patents

Abstract

FIELD: technology for controlling large-dimensional objects.

SUBSTANCE: in accordance to method, volumetric moisture of concrete is measured in zone of placement of controlled object, open parts of pipes and elements of fire ladder and borders are scanned in their fastening zone for determining zones of concentration of mechanical strains, estimated further is degree of corrosion of open sections of pipes or ladder elements and borders in their fastening area by means of geophysical complex, thicknesses of open walls of pipes or ladder elements and borders are determined in area of fastening, ultrasound flaw detection is performed over welded connections and parts of pipes of communications or section of fire ladders and borders are considered flawed on condition of detection on basis of results of diagnostic operations of degree of corrosion, equal to or exceeding 20 percents of loss of thickness of pipe wall or profile from original one, or loss of thickness of pipe wall or its casing in opening area exceeding 0,4 mm compared to section of pipe having no corrosion damage, or profile of ladder and border compared to section of profile, not having any corrosion damage, or in case of moisture level of concrete of inter-floor bridging or a wall, exceeding 2,5 weight percents or 70 specific units for GANN devices with electrode of 50V or on detection of defects in welded connections of pipes or in pipes.

EFFECT: increased information capacity and precision of diagnostics.

2 cl, 5 dwg

Description

The invention relates to instrumentation and can be used for non-destructive testing, assessment and prediction of the technical condition of the structure and engineering structures, for example, potentially hazardous sections of pipelines, including gas pipelines, during the entire period of their operation. The invention allows to reliably identify various types of defects, including in sections of pipelines embedded in the concrete mass and to which there is no direct access.

A known method for diagnosing the technical condition of main oil and gas pipelines during their operation, including the continuous movement of a flaw detector with an electro-acoustic transducer along the pipe wall, the generation of ultrasonic vibration pulses by an electro-acoustic transducer, non-contact transmission of ultrasonic vibrations pulses through the pumped medium into the pipeline wall, excitation of ultrasonic vibrations in the wall pipeline reflection of ultrasonic vibrations from non-uniform the similarities of the material of the pipeline wall, transmitting the reflected ultrasonic vibrations from the pipeline wall to the electro-acoustic transducer, recording the reflected ultrasonic vibrations and determining from the results of measurements the nature, dimensions and location of defects in the pipeline wall. (RU No. 2153163, publ. 2000.07.20).

The disadvantage of this method is that it allows you to get information only about the presence of defective sections of pipelines and only in those places to which direct access is possible. Parts of pipelines to which access is difficult, for example, due to the fact that part of the pipe is immersed in the ground or passed through the embedment, cannot be tested. In addition, this method does not allow to identify the causes of defects, for example, a local decrease in the wall thickness of the pipeline.

A known method of detecting corrosion damage to pipelines, according to which the studied pipeline is divided into sections. Pits are dug out at the boundaries of the plots, the electrical resistances of the plots and the electrical resistances at the marginal zones of these plots (in pits) are measured using a four-electrode circuit. The pipe wall thickness and outer diameter are also measured at the marginal zones. From these measurements, the specific resistance of the pipe metal is calculated. Using the calculated specific resistance of the pipe metal, the electrical resistances of the sections of the used pipe size with the minimum allowable wall thickness are calculated and the measured and calculated values of the resistances of these sections are compared. The deviation of the measured resistances from the calculated one judges the presence and degree of corrosion damage to the metal in these areas. To increase the accuracy of the measurements, the corresponding current and potential electrodes, when measuring the resistance, are carried at distances no less than two pipe diameters (RU No. 224297, 2005.01.10).

The disadvantage of this method is the complexity of its implementation and the low reliability of the results due to the influence of a large factor of external conditions on the course of electrical processes.

A known method of non-destructive diagnostics of local corrosion damage to pipelines is that soil sampling is carried out, suspensions of microorganisms are isolated, the suspension obtained is incubated with a dried mixture of mineral salt solution, incubation is carried out until the indicator color develops, light absorption intensity is measured, the color index is determined, carry out statistical cluster analysis using the method of principal components. Then, a graph is constructed that reflects the spectrum of substrate consumption, and the zones highlighted on the graph are compared; according to the grouping of the signs of the analyzed soil samples on the graph, they are judged about the presence of corrosion damage to the pipeline, about the presence of biodegradation of the pipeline coating and biodegradation of pollutants in the soil. (RU No. 2140628, 1999.10.27).

The disadvantage of this method is that chemical analysis allows to obtain data on the presence of the results of the corrosion process and on the nature of its occurrence, but these data relate entirely to a large section of the pipe and do not allow to establish the location of the defect. For example, according to the results of chemical analysis, it was found that a corrosion process takes place in this section of the pipe, but the degree of damage to the pipe is not clear, that is, is the thickness of the pipe sufficient to maintain pressure or if it needs to be replaced completely.

The present invention is aimed at solving the technical problem of providing comprehensive diagnostics of pipelines by comparing data on pipe wall thicknesses in its various sections with the results of the analysis of the causes of the corrosion process both in open sections of the pipeline and in areas embedded in concrete.

The technical result is an increase in the information content and accuracy of diagnosis.

The specified technical result is achieved by the fact that according to the method for diagnosing the technical condition of metal engineering structures and communications of a building, mainly sections of the internal gas pipeline in the building and fire ladders and roof protections of the building, which includes diagnostic work for finding defects,

- measurement of the volumetric moisture content of concrete floors or walls for utilities or in the area of the fire escape to the wall and fences to the roof,

- scanning of open sections of pipes of engineering communications or sections of a fire escape and fences in the area of their fastening by a geophysical complex to establish zones of concentration of mechanical stresses by an abrupt change in the magnitude of the scattering magnetic field Нр relative to Нр = 0,

- determination using an ultrasonic thickness gauge of the degree of corrosion of exposed sections of utilities pipes or their cases in the floor or wall or sections of the fire escape and fences in the area of their fastening;

- determination by means of ultrasonic thickness measurement of pipe wall thicknesses of open sections of utilities or sections of the fire escape and fences in the fastening area,

- conduct ultrasonic flaw detection of welded pipe joints in open areas of utilities or sections of the fire escape and fences in the area of fastening,

- and establish defective sections of pipes of engineering communications or sections of fire ladders and fences, provided that according to the results of diagnostic work, the degree of corrosion equal to or more than 20 percent of the loss of pipe wall thickness or profile from the initial one, or the loss of pipe wall thickness or its case at the opening point is greater 0.4 mm in comparison with a pipe section that does not have corrosion damage, or the profile of a ladder and a fence, compared with a pipe section that does not have corrosion damage, or with humidity concrete floors or walls in excess of 2.5 weight percent or 70 cu for GANN instruments with a B 50 electrode or when defects are detected in welded pipe joints or in pipes.

In addition, when defective pipes of engineering communications or sections of fire escape ladders and fences are installed, additional diagnostic work is carried out, which includes determining the alkaline liquid phase of the amount of concrete chloride ions in the places where pipes pass or in the places where fire ladders and fences are fixed and measuring the surface potential of steel pipes or case in the interfloor overlap or wall or steel elements of the fire escape and fences in the area of their fastening.

These features are significant and are interconnected with the formation of a stable set of essential features sufficient to obtain the desired technical result.

According to the present invention, a method for comprehensive diagnostics of the technical condition of metal engineering structures and communications of a building, mainly sections of the internal gas pipeline in the building and fire ladders and fences of the roofs of the building at the places of their closure, includes diagnostic work to search for defects consisting in measuring the volumetric humidity of the concrete of the floor or walls for utilities or in the area of attaching the fire escape to the wall and the fences to the roof, scanning by geophysical with the GFK-1 complex of sections of engineering communications pipes or sections of a fire escape and barriers in the area of their fastening to determine the method of sealing, scanning of open sections of pipes of engineering communications or sections of a fire escape and barriers in the area of their fastening by a geophysical complex to establish zones of concentration of mechanical stresses an abrupt change in the magnitude of the scattering magnetic field Нр relative to Нр = 0,

- determination using an ultrasonic thickness gauge of the degree of corrosion of exposed sections of engineering pipes or their cases in the floor or wall or sections of the fire escape and fences in the area of their fastening;

- determination by means of ultrasonic thickness measurement of pipe wall thicknesses of open sections of utilities or sections of the fire escape and fences in the area of fastening,

- the implementation of ultrasonic inspection of welded pipe joints in open areas of utilities or sections of the fire escape and fences in the area of fastening,

- and the establishment of defective sections of pipes of engineering communications or sections of fire ladders and fences, provided that according to the results of diagnostic work, the degree of corrosion equal to or more than 20 percent of the loss of pipe wall or profile thickness from the initial one, or the loss of pipe wall thickness or its case at the opening point is greater 0.4 mm compared with a pipe section that does not have corrosion damage, or a ladder and guard profile, compared with a pipe section that does not have corrosion damage, or with humidity concrete floor slabs or walls, exceeding 2.5 percent by weight or 70 cu for GANN instruments with a B 50 electrode or when defects are detected in welded pipe joints or in pipes.

When defective pipes of engineering communications or sections of fire escape ladders and fences are installed, additional diagnostic work is carried out, including determining the alkaline liquid phase of the quantity of chloride ions of concrete in the places where the pipes pass or in the places where the fire ladders and fences are fixed, measuring the surface potential of the steel pipe or case in interfloor overlap or wall or steel elements of the fire escape and fences in the area of their fastening.

Below are discussed in detail the individual operations of the method with an indication of the means of their implementation. At the same time, the gas pipeline diagnostics is considered in relation to the indoor pipeline of the room.

Before diagnosis, by means of the GFK-1 geophysical complex produced by the applicant, for hidden areas in the field of sealing pipes and fire escape links and barriers, a gas pipeline construction plan is constructed in the room, and if it is not possible to identify the path, the surface is scanned with a georadar to obtain the direction and the depth of the pipeline.

1. Measurement of volumetric moisture content of concrete of the interfloor overlap 1 or of the wall for utilities or in the area where the fire escape is attached to the wall and to the roof railings. The cause of corrosion can be overmoistening of the environment of the place (wall) of the pipeline 2. The degree of humidity also affects the speed of the corrosion process. The determination of the volumetric moisture content determines the picture of the passage of the corrosion process in a given place.

First of all, the presence of moisture sources within a radius of 5 m (2 m for domestic premises) from the gas pipeline is established, from which humidification can occur either directly on the surface of the gas pipeline or its case, or on the moistening of the building structure through which the gas pipeline passes.

Moisture sources may include:

- open sources of moisture (atmospheric moisture penetrating into the room through the roof, windows, unsealed joints of building structures, technological openings in building structures, etc., condensate formed on the surface of the gas pipeline in the places of the “heat-cold” transition, especially in humid premises, household sources of moisture, such as showers, sink baths, garbage chutes, etc., process pipelines and tanks from which moisture can leak and moisturize the surface of the gas pipeline, or the transition point pipeline through the building structure;

- closed sources of moisture (steam or hot water pipelines, cold water pipelines, sewage, process pipelines and reservoirs, from which moisture leakage and humidification of the surface of the gas pipeline or the place where the gas pipeline passes through the building structure are possible).

Visual determination of the degree of humidity by the presence of external signs is necessary for a qualitative assessment of the results of local measurements of volumetric humidity in the zone of passage of the gas pipeline through the floors.

The volumetric moisture content of concrete is measured within a radius of 30 cm from the passage of the gas pipeline through the floors. When using the GANN UNI-1 moisture meter with an electrode B 50 to measure the volumetric humidity of the interfloor overlap, the electrode should be installed so that its longitudinal axis is perpendicular to the surface of the measured building structure. The sensor must touch the measuring end (sphere) of the surface to be monitored. Measurements are made along one line directed perpendicular to the long side of the floor slab (in case the floor is made of reinforced concrete). At least 5 measurements will be taken at the place of the most probable waterlogging at a distance of no more than 4-5 cm from each other. It should be borne in mind that metal reinforcement located in concrete can affect the readings of the device. The influence of reinforcement can be reduced by measuring at points farthest from adjacent reinforcing bars. The approximate distance between adjacent rods can be determined by increasing the readings of the device, with continuous rectilinear scanning of the concrete structure perpendicular to its long side. The length of the scanning area must be at least 50 cm. The scanning location must be dry or evenly moistened.

When using the device "Kaisson VI-D1" 3, attach the sensor 4 of the device to the measured surface, achieve a snug fit of the sensor to the surface (see figure 1), excluding oscillations of the device, and take the count from the scale of the device. Measurements are carried out along one line directed perpendicular to the long side of the floor slab (if the floor is made of reinforced concrete). Also, at least 5 measurements will be taken at the place of the most probable waterlogging at a distance of no more than 4-5 cm from each other.

If, as a result of volumetric moisture measurements, it is established that the humidity of the concrete floor or wall exceeds 2.5 weight percent or 70 cu for GANN devices with an electrode of 50, it is considered that the standard humidity values are exceeded. Exceeding the volumetric humidity of the standard values indicates an increase in the rate of corrosion processes in this zone.

However, the obtained results on volumetric humidity do not provide reliable information about actual defects due to corrosion (for example, pipes could be recently replaced and the walls did not lose their thickness).

2. To assess the technical condition of sections of pipelines 2 passing through the interfloor overlap 1, an opening of the pipeline section (figure 2) or its case 5 (figure 3) passing through the interfloor overlap is performed. In Fig.1 shows a diagram of the opening of concrete in the area of passage of the pipeline through the overlap with a protruding case, and Fig.2 - with monolithic case 5.

Based on many years of experience in technical diagnostics of internal gas pipelines, it has been established that the corrosion process proceeds most intensively in the zones of contact of the gas pipeline or its case with the building structure and in places located near the surface of the building structure through which the pipeline passes.

After opening, visual control of the degree of corrosion of the case or pipe in the interfloor overlap of the gas pipeline is carried out according to the following criteria.

Weak - surface layer of corrosion (light rust coating 6), wall thickness varies within the tolerance stipulated by GOST.

Acceptable - corrosion has the same structure as weak, the surface is more uneven, small uneven scales peel off, after cleaning small shells ⌀ 1-2 mm and a depth of 0.2-0.3 mm are visible, the corrosion is loose and easily removed with a knife (color corrosion red, brown).

Strong - the pipe is covered with a dense layer of corrosion products, during flaking, thick flakes peel off (plates), shells are ⌀ 2-4 mm and a depth of 0.3-0.6 mm (color of corrosion is brown, dark brown), corrosion penetrates into concrete and It paints its surface on the cleaved surface (at the point of contact with corrosion products) in brown or red color.

Very strong - a dense layer of corrosion products, peeling off with enlarged plates or pieces with rectangular ends; after cleaning, a continuous thinning of the pipe wall (neck) is visually detected, the color of corrosion is dark brown, brown, almost black at the point of contact of the corrosion products with the pipe.

If at the initial moment of opening a significant layer of corrosion products on the gas pipeline is detected, the pipe wall thickness is measured using an ultrasonic thickness gauge in the section from the pipe section with intact walls to the detected place of severe corrosion, conducting measurements of the gas pipe wall thickness distantly until a value is obtained thickness less than 2 mm. A detection point of a minimum allowable thickness of 2 mm indicates the need to replace a corroded pipe section.

3. Determination by means of ultrasonic thickness metering of the wall thicknesses of the pipes of the open sections of utilities or sections of the fire escape and fences in the area of fastening.

Measurement of the wall thickness of the pipeline is carried out by ultrasonic thickness gauges.

First, if necessary, they clean the surface of the exposed section to measure the wall thickness of the gas pipeline or case. Perimeter and point pipe sections are cleaned to ensure acoustic contact. To carry out measurements of the residual wall thickness of the pipe, depending on the degree of corrosion, the number of control points per 1 meter of the surface of the controlled gas pipeline is selected. These points should be especially tightly located on the sections of the gas pipeline that are most susceptible to corrosion. For gas pipelines not subject to corrosion, 1 control point is taken for 2-5 meters of the gas pipeline length. In each apartment, regardless of the length of the plot, at least 1 thickness measurement should be made on each diameter.

Ultrasonic flaw detection of gas pipeline sections passing in floors and walls is carried out, for example, using a P 121-1.25N transducer (item 7), or a specialized UD-21P flaw detector, or any general purpose flaw detector. Sounding is performed by perimeter (ring) scanning (trajectory - pos. 8) along the surface of the pipe at the minimum possible distance from the controlled area (figure 4). To increase the effectiveness of control, it is necessary to scan from two sides of the controlled area (conditionally "bottom" and "top" of the floor).

Ultrasonic flaw detection using the "normal waves" method is carried out in order to identify the following types of defects:

- lack of fusion, non-fusion and pores in longitudinal welds;

- cracks in the body of the gas pipe;

- corrosive ulcers.

The quality of controlled sections of gas pipelines is assessed when an echo signal from a defect is detected within a strobe pulse by measuring its amplitude (measurements are performed according to the directions of the flaw detector technical description) and the echo signal is fixed on the scan line of the flaw detector. A defect is considered unacceptable if the amplitude of the echo signal from it exceeds the amplitude of the echo signal from the reference reflector located in a fixed place on the scan line of the flaw detector.

4. Scanning of open sections of pipes of engineering communications or sections of a fire escape and barriers in the area of their fastening to establish zones of concentration of mechanical stresses by an abrupt change in the magnitude of the scattering magnetic field Нр relative to Нр = 0.

The determination of stress concentration zones begins with a scan of suitable linear sections of the gas pipeline. The measurement of Hp (scattering magnetic field) is carried out along any pipe forming tube that is most convenient for control. An abrupt change in the sign of the Нр value indicates the concentration of residual stresses along the Нр = 0 line for a specific pipe section.

5. The implementation of ultrasonic flaw detection of welded pipe joints in open areas of utilities or sections of the fire escape and fences in the area of fastening. Ultrasonic testing of welded joints is carried out using "chord type" piezoelectric transducers in accordance with the "Methodology for ultrasonic testing of butt ring joints of steel and polyethylene gas pipelines (for chord type transducers"), agreed by the State Technical Supervision Service of Russia. A specialized ultrasonic flaw detector-recorder UD-21R is used. Every second welded joint is subject to verification. If a defective weld is detected, a check is made for each weld.

Pipe sections of engineering communications or sections of fire ladders and fences are recognized defective provided that, according to the results of diagnostic work, the degree of corrosion equal to or more than 20 percent of the loss of the pipe wall or profile wall thickness from the initial one, or the loss of the pipe wall thickness or its case at the opening point is greater than 0, 4 mm in comparison with a pipe section that does not have corrosion damage, or a ladder and guard profile, compared with a pipe section that does not have corrosion damage, or with concrete moisture and the intermediate floor or wall, exceeding 2.5 percent by weight or 70 cu for GANN instruments with a B 50 electrode or when defects are detected in welded pipe joints or in pipes.

If it is established that the pipes of engineering communications or sections of fire ladders and fences are defective, then additional diagnostic work is carried out, including measuring the surface potential of the steel pipe or case in the floor or wall or steel of the fire ladder elements and fences in the area of their fastening and determining the number chloride of concrete ions in places of passage of pipes or in places of terminations of fastening of fire ladders and protections. These measurements are carried out to establish the nature of the occurrence of severe corrosion at the site of incorporation.

The presence of electrical interaction between the pipe and the case forms the process of electrocorrosion caused by stray currents. To eliminate this phenomenon, it should be provided for: pipes in the ceilings are laid in steel embedded parts - cases. However, during operation or as a result of violations of the technology of laying both pipes and wiring, conditions arise for the appearance of electrical interaction between the pipe and the case, accelerating pipe corrosion.

Measurement of the surface potential of steel pipes or cases in the floor or wall or steel elements of the fire escape and fences in the area of their fastening is carried out using multimeters 9 (Fig. 5), which have the function of determining resistance with an accuracy of +/- 1 Ohm and measurement limits 0- 10 megohms (e.g. type 43313 digital multimeter).

Prior to the measurement, the operability of the multimeter (voltmeter) is checked by measuring the surface potential of the steel of the pipe or case with respect to concrete (Fig. 5). To do this, irrigate the cleaned area with water. Water must be absorbed. If the humidity of the concrete exceeds 2.7%, wetting can be omitted. The potentiometer terminal is connected to the cleaned surface of the pipe or case, and the copper-sulfate electrode 10 is pressed to the cleaned and wetted surface of the concrete and the readings are taken.

To measure the surface potential of the steel of the pipe or case, it is necessary to strip the pipe section 2 and the case to a metallic luster and connect one terminal of the device to the pipe and the second to the case. If the pipe-sheath resistance value is different from 0 or ∞, an ultrasonic flaw detection should be performed on this section of the gas pipeline using the "normal waves" method.

In the case of metal contact between the pipe and the case, the resistance will be zero or infinity if there is a reliable insulator between them. When obtaining electrical resistance values of more than 1-2 kOhm, there is a high probability of contact between the pipe and the case by corrosion products.

To determine the alkalinity of the liquid phase of concrete in the places where the gas pipeline passes, the method of determining the amount of chloride ions of concrete or other material from which the building structure is made is used.

Chlorides and sulfates are often dissolved in natural and industrial waters, which under certain conditions can cause corrosion of steel reinforcement and concrete, affect the hardening of cement paste and concrete, and also form efflorescences on the surface of structures. Especially dangerous is the effect of chloride salts on high-strength steel reinforcement, prone to stress corrosion.

The permissible content of Cl ions in mixing water (350 mg / l) means that concrete with a mixing rate of 270-450 kg and water 180-220 l / m ³ is introduced with mixing water of 0.027-0.038% chlorides in terms of CaCl relative to mass of cement. Such a quantity of chlorides does not cause local corrosion of the surface of steel reinforcement. For concrete with the above cement and water content, this means that 0.09-0.13% of chlorides, calculated on CaCl, relative to the mass of cement, are added to it. In dense concrete, such a quantity of chlorides does not cause corrosion of steel reinforcement. Slight surface corrosion is possible only in places with defective concrete structure. In concrete, constantly saturated with water, corrosion of the reinforcement develops slowly, since the access of oxygen is very limited. However, on the surfaces of steel pipes embedded in concrete constantly saturated with water, the corrosion process is greatly increased.

Before measuring the amount of chloride ions, it is necessary to clean the area on the surface of the building structure or use the finished cleaned surface after measuring the surface humidity. Using a syringe or spray gun, apply a 1% solution of silver nitrate in an aqueous solution of nitric acid (1:40) to the prepared site. After 2-3 minutes, apply a 5% solution of potassium dichromate to the area moistened with the first solution, and immediately fix the color of the concrete surface. The amount of chloride ions is determined in accordance with the table:

Concrete Surface Color The amount of chloride ions in% by weight of cement Points Yellowish green 0.5% four Reddish-brown color of a light tone with certain greenish spots 0.4-0.5% 3 Red-brown color sometimes interspersed with a yellowish tint 0.2-0.4% 2 Intense red-brown color Less than 0.2% one

This control allows you to establish the effect of salts dissolved in water, such as chlorides, on the structure of concrete and, accordingly, on the pipe material in the formation of the corrosion process.

As a result of the measurements, defective sections of the engineering communications pipes or sections of fire ladders and fences are installed according to the following conditions:

- according to the degree of corrosion equal to or more than 20 percent of the loss of the wall thickness of the pipe or profile from the original, or the loss of the wall thickness of the pipe or its case at the opening point is more than 0.4 mm compared to a pipe section that does not have corrosion damage, or the profile of the ladder and fencing in comparison with the section of the profile that does not have corrosion damage;

- or when the humidity of the concrete of the floor or wall exceeds 2.5 weight percent or 70 cu for GANN devices with an electrode of 50;

- or if defects are detected in the welded joints of the pipes or in the pipes.

With this integrated diagnostic approach, it is possible to maintain the pipelines of engineering communications or sections of fire ladders and fences in a fully technically conditioned condition, the same in all sections for a given period of operating time within the framework of the service life.

The present invention is industrially applicable, as it is based on a new interconnection of various measurements carried out using known means.

Claims (2)

1. A method for diagnosing the technical condition of metal engineering structures and communications of a building, mainly sections of the internal gas pipeline in the building and fire escape and fencing of the roofs of the building, including diagnostic work for finding defects, which consists in volumetric moisture measurement of concrete floors or walls for utilities or in the area of the fire escape to the wall and the fences to the roof, scanning by geophysical complex "GFK-1" of pipe sections of engineering communications or sections of a fire escape and fences in the area of their fastening to determine the method of sealing; scanning open sections of pipes of engineering communications or sections of a fire escape and barriers in the area of their fastening to establish zones of concentration of mechanical stresses by an abrupt change in the magnitude of the scattering magnetic field Нр relative to Нр = 0, determination using an ultrasonic thickness gauge of the degree of corrosion of exposed sections of engineering pipes or their cases in the floor or wall or sections of the fire escape and fences in the area of their fastening; determination by means of ultrasonic thickness measurement of pipe wall thicknesses of open sections of utilities or sections of fire escape and fences in the area of fastening, the implementation of ultrasonic flaw detection of welded pipe joints in open areas of utilities or sections of the fire escape and fences in the area of fastening and the establishment of defective pipe sections of utilities or sections of fire ladders and fences, provided that the results of diagnostic work determine the degree of corrosion equal to or more than 20% loss of the wall thickness of the pipe or profile from the initial one, or the loss of wall thickness of the pipe or its case at the opening point is greater than 0 , 4 mm in comparison with a pipe section that does not have corrosion damage, or a ladder and guard profile, compared with a pipe section that does not have corrosion damage, or with concrete moisture floor covering or wall exceeding 2.5 wt.% or 70 cu for GANN instruments with a B 50 electrode, or when defects are detected in welded pipe joints or in pipes. 2. The method according to claim 1, characterized in that they carry out additional diagnostic work, including determining the amount of chloride ions of concrete in the places where pipes pass or in the places of fixing fire ladders and fences and measuring the surface potential of the steel pipe or case in the floor or wall or steel elements of the fire escape and fences in the area of their fastening.

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