MIL OSI Translation. Region: Russian Federation –
We will tell you how pipes are tested for strength and how long it takes.
The season is in full swing in Moscow hot water shutdown… Temporary restrictions (in Moscow, the water is turned off for 10 days) are necessary to carry out hydraulic tests on the networks. While the pipes are taken out of service, experts check them for strength, which helps to avoid accidents in the next heating season. Why it is necessary to turn off hot water in the summer and what tests are carried out by MOEK specialists – we answer the most important questions.
How is the heat supply system arranged in Moscow?
Moscow has a centralized heat supply system. Heat is generated by 13 large thermal power plants and one and a half hundred small thermal power plants. The total length of heating networks in the capital is about 17 thousand kilometers. This is twice as much as the road from Khabarovsk to Moscow. And the length of the highways from the CHP plant to a particular house can be from one to 15 kilometers.
The pipe itself consists of sections of different diameters. The pipes were laid in different years and using different technologies. The pipelines through which the coolant flows (specially prepared industrial water, purified from salts and other impurities, so that deposits do not accumulate on the pipe walls) inevitably undergo deformation. To keep the networks working properly all year round, they are pressure tested and repaired.
What is hydraulic testing and what is it for?
Since the capital has a centralized heat supply system, it is impossible to carry out hydraulic tests without phasing out consumers. Therefore, it is in the summer (after the end of the heating season) that hot water is turned off, and MOEK specialists conduct hydraulic tests. They are necessary in order to prevent major incidents and ensure uninterrupted supply of hot water and heat to the apartments of Muscovites. Today, pressure testing is the most reliable method of preparing for winter peak loads.
What work is carried out during hydraulic tests?
All work on heating systems is carried out according to the schedule, so hot water is not turned off at the same time throughout Moscow: everything happens in stages.
First, the main networks are divided into sections, then they are taken out of service in turn, due to which the supply of the coolant that heats the water to the heating points stops. At this time, the pressure in the pipe is increased and the temperature of the carrier is reduced. In such conditions, the strength of pipelines, joints, valves and other elements is checked.
The state of communications is assessed by checkpoints. If the pressure drops on one of them, it means that the network section is damaged: diagnostic equipment helps to find it exactly. This area is then excavated, repaired, or completely changed.
After repair, hydraulic tests are carried out again. If everything is in order, the site is buried, and the hot water supply is resumed. All this takes no more than 10 days from the moment of disconnection.
Do technological failures occur in heating systems in summer?
Most incidents on heating systems in the summer occur just during hydraulic tests on already disconnected sections. But such cases are not accidents per se.
During hydraulics, the pressure in the pipeline is increased, which makes it possible to detect the damaged area. And if a pipe breakthrough occurs somewhere in the summer, it means that the specialists have found an unreliable section of the heating network and promptly fix the problem. This prevents accidents during the heating season.
What modern technologies are used when laying new pipes?
The new pipes use polyurethane foam insulation. It reduces heat loss and protects the network from external corrosion. Moreover, the new pipes are equipped with a remote monitoring system. In other words, the pipelines are equipped with wet sensors: they identify potential problem areas.
In preparation for the heating season, specialists use non-destructive testing methods, for example, in-line diagnostics. During it, a scanner is launched into the tube, which examines its condition with ultrasound.
Also of interest is the method of pipelines restoration with a sleeve polymer coating. If a leak is found, a synthetic sleeve with a polymer is pulled inside the pipe, which strengthens its walls and significantly extends the service life.
Are the pipes checked only in summer or at other times of the year too?
Already at the end of winter, specialists begin hydraulic tests where this can be done without turning off the hot water in the apartments. But the main large-scale work on checking the heat supply system begins after the end of the heating season, since hydraulics is carried out not only on hot water networks, but also on heat supply pipes.
EDITOR’S NOTE: This article is a translation. Apologies should the grammar and or sentence structure not be perfect.