There are different technologies for processing pipes, but more often they are soldered, welded or pushed into a socket. However, in some cases, for their normal operation, pressure testing of pipes is required, which checks the integrity of the structure and excludes leakage.
Crimping of copper pipes is performed to restore the integrity of the line and fittings. It provides for the processing of a small segment, previously isolated from the main line and tested under the influence of the maximum allowable pressure.
What is pipe crimping
Pressure testing of steel pipes is carried out by pumping cold water or compressed air into a separate section in a large volume, due to which pressure is created, the strength of which is close to critical. If during this operation the system passes the test and remains tight, the expert recognizes it as fit for subsequent operation. If leaks appear and a breakthrough occurs in the weak link, this is displayed on the pressure gauge and a decision is made on the need to refine the proven branch.
When pressing is necessary
Pressurization with air in the apartment is mandatory carried out immediately after the completion of installation work (before the line is put into operation) or to check old systems after restoration work. Pressure testing is also required to test systems that are installed using the coupling technology, since the place where the fitting is joined to the pipe is one of the weakest sections of the pipeline.
Also, air testing of the pipeline is required due to the seasonal characteristics of the operation of the pipeline. For example, before starting the operation of a central heating system, a pressure test is performed to check all sections of the heating main.
Important! If the object is equipped with a plastic pipeline, pressure testing is periodically performed to control the integrity of the pipeline, and is also carried out every time after cleaning. This need arises because of the risk of damage in certain areas of the water supply or joints during its cleaning.
Another situation where such a check is required is the equipment of water wells, but here pressure testing is performed using a modified technology. The pipe is located in the well shaft from the beginning, which is why the risk of leaks from it is not considered a key problem. The procedure is carried out in order to understand the depth of water intake from the well, on which the quality of the water consumed depends. In this regard, during pressure testing of wells, it is checked whether the transported liquid does not come into contact with the upper layers in the mine, as this can spoil it.
Preparation for the procedure
According to the rules of pressure testing of pipelines, first of all, a visual inspection of the controlled section of the pipeline is performed in order to make sure that there are no obvious defects, such as the loss of important parts, corrosion, and others. If such violations are found, they should be eliminated before proceeding with pressure testing. If during the test there is a working environment in the system that cannot be used for testing the pipeline, the site must be completely freed from it.
After that, the pipes are thoroughly washed to get rid of rust, scale, as well as organic and inorganic deposits. In some cases, flushing is performed using a special compressor, and as a result, a check is performed by examining the inner surface of the pipeline, a part of which (about 0.5 m in size) is preliminarily cut out for study.
If the injection equipment is not equipped with a check valve that blocks the movement of the working medium towards the source, and a pressure gauge, then they are installed separately after all tests are completed.
Important: If the pipeline to which the residents of an apartment building are connected is checked, the heating unit associated with the system is checked first. The reason for this is that the thermal unit is tested under higher pressure.
Next, the area to be checked is completely covered and carefully sealed. It is important to completely cut off the tested branch from the central water supply before pressure testing by closing the shutoff valves on both sides. If a sewer pipeline is being tested, wooden, plastic or wooden plugs are installed on it.
Crimping machines, pipe crimping pumps
Depending on how powerful the pump will be used when performing crimping, the accuracy of the results and the duration of the work change. Low-power equipment will build up the required pressure for a long time, since the strength of a simple pressure tester is not enough to quickly fill a massive pipeline with the required volume of liquid or air, and if there are leaky joints in the system, the final results will be distorted.
In this regard, when choosing a pump for pressure testing, one should start from the volume of the system being tested. If you need to check the home system, it is enough to use a blower that will pump up to two or three liters every minute, while checking the heating main requires the use of circulation pumps, which ensure the movement of fluid inside the pipeline.
After the pipeline is prepared, a pressure source is connected to the treated area, which is a special pump designed to carry out such control operations, or a conventional pump, which starts the liquid in motion through the system.
The pump is connected to a branch, which must be equipped during the design of the entire system:
- if the heating system is checked, special taps are used on each radiator;
- pressure testing of the water supply system is carried out through the tap connection pipe;
- when working with sewer systems, you need to insert the pump nozzle into the revision — a tee, which is installed in the outlet line in increments of 40-50 meters.
Next, air or liquid is pumped into the system and the pressure stability in the system is measured. This stage is key, since air is pumped into the system through the pump through the back pressure valve, which blocks its movement in the opposite direction.
The pressure force will vary depending on what material the pipes used at the base of the system are made of. For a cast-iron pipeline, a pressure of 1.5 atmospheres is sufficient, while plastic non-pressure pipes can be tested under pressure up to 2 atmospheres. If checking pressure pipes is required, the pressure should be at the level of 10-15 atmospheres.
The pressure gauge is located behind the back pressure valve, otherwise it will not be possible to measure any real results.
The final compression process looks like this:
- Air is pumped in. At the same time, the pressure gauge readings are monitored to check the pressure.
- After the internal pressure reaches the desired level, the pressure pump is switched off.
- The primary pressure is fixed, the system is left in the current state from six to eight hours.
- After the specified period of time, the primary value is compared with the current result.
Only in the event that the obtained indicators turn out to be the same in the end, we can say that the system under test was hermetic. Otherwise, leaks appeared somewhere in the pipeline and it needs to be finalized. The work must be carried out by a specialist who knows what correct pipe pressure testing is and how it should be carried out, otherwise the system check may be useless.
SNiP and safety measures during pressure testing
The procedure for testing the pipeline and the safety standards that must be followed during its implementation are regulated by the relevant sections of SNIP:
- 05.01-85 — rules for working with internal sanitary systems;
- 05.04-85 — rules for testing external drainage systems;
- 41-01-2003 — procedure for testing ventilation, heating and air conditioning systems.
There are also several industry regulations that govern the rules for checking industrial pipelines in various areas.
These documents regulate what pressure must be to check the integrity of the pipeline. This value depends, first of all, on what material the pipes in the system are made of, the permissible minimum wall thickness, as well as the height of the upper and lower elements.
When performing tests, to ensure the safety of all involved in the process, it is important to ensure that the recommended pressure value is not exceeded. To achieve this force, you should choose the right crimping machine or buy a model equipped with a limiter.