Description of control pressure testing of gas pipelines in an apartment building

The most important condition for the operation of the gas supply system is the complete tightness of pipes and connecting elements. To make sure that the system is ready for action, a control pressure test of the gas pipeline is performed. Without this last test, it is prohibited to commission any level of pipeline.

The need for control pressure testing of the gas pipeline

Pressure Testing is a procedure used to test a closed-loop system operating under pressure for strength and tightness. The test is carried out by pumping air into the circuit at a pressure higher than the operating pressure in the network. At the same time, it is easy to detect the smallest errors when joining pipes or welding seams.

After pressure testing, the selection committee draws up an acceptance certificate and allows you to start the gas pipeline. If any problems were found, the commission issues an order to eliminate the identified defects. The acceptance certificate is signed by the installation and operating company. Frequency not established: tests are performed as needed.

Preparatory work

Before the control pressure testing of the internal gas pipeline, certain preparatory work is performed:

• verification of the actual layout of the gas pipeline and its compliance with the data of the technical documentation;
• selection of the installation site for all plugs, sensors, meters and compressor;
• employees undergo additional or repeated training on safety compliance and examination regulations.

Pressure testing of a gas pipeline and gas is performed not only when the system is put into operation in an apartment building or at an enterprise. The test is also performed when connecting new equipment, after repairing and replacing part of the pipes.

Norms and rules for crimping

Control pressure testing of internal gas pipelines is regulated by GOST R 54983 2012. General rules are the same for testing any part of the circuit under high and low pressure.

1. Pressure testing of gas equipment and the pipeline with air is performed before the line is cut into the central line.
2. To check, air is pumped into the cut-in section of the gas pipeline at a pressure of 100 kPa and held for at least 60 minutes. Measure the pressure in the circuit with a pressure gauge. The accuracy class of the device must be less than 0.6.
3. If the circuit is tight, the overpressure is maintained until the end of the pressure test. If the pressure gauge registers a decrease in pressure, there is a leak in the pipe. According to SP 62.13330.2011, re-pressure testing is done six months after the control one.

Air or inert gas is used for pressure testing.

In an apartment building

Pressure testing of an internal gas pipeline inside a house is performed after an external inspection. After servicing, the gas pipeline is checked for strength. Air is pumped into the circuit with a pressure of 1 kgm / sq. see This is how they check the pipeline from the switch at the entrance to the house or to the staircase to the cranes on holidays to the devices. A complex gas pipeline is checked by dividing it into separate sections.

If gas meters are installed in the building, they are turned off during pressure testing, and the sections are connected with a jumper. The test is started 3 hours after the rise in pressure. The possibility of leakage is checked with soapy water. If defects are found, the commission fixes them.

Pressure testing of gas inner pipes includes a tightness test.

1. The gas pipeline is filled with air under pressure of 400 mm of water Art. with running meters and gas appliances. If there are no meters in the circuit, air is pumped under a pressure of 500 mm of water. Art. The gas supply system has passed the test if, within 5 minutes, the pressure drop does not exceed 20 mm of water. Art.
2. When connecting new gas equipment to a gas pipeline already operating in an apartment building, pressure testing is carried out with gas. The emulsion is applied to all stripped and threaded connections to check for leaks.
3. Automatic devices are checked only for density. The air pressure during pressure testing reaches 500 m of water. Art.

It is strictly forbidden to cover up defects of any type with putties.

Underground gas pipeline

Pressure testing of an underground gas pipeline is performed after installation in trenches and full or partial backfilling - at least 20 cm. Each section of the line, from plug to plug, is checked separately.

1. Testing begins with air injection under test pressure. Maintain the time required for temperature equalization.
2. Measurements are performed with pressure gauges with an accuracy class of 0.4 or 0.6.
3. The section of steel and polyethylene gas pipelines is pressurized separately.
4. Pressure testing of underground external gas pipelines, laid in cases, is carried out three times. For the first time immediately after welding and before laying. Then after backfilling in the trench and, finally, together with the entire gas pipeline.
5. The inspection of multilayer pipes is carried out in 2 stages. First, it is tested for strength by pumping air for 10 minutes at a pressure of 0.1 MPa, and then it is tested for tightness under a pressure of 0.015 MPa.

Testing of special technical devices is carried out according to standards for lines with the same pressure.

Internal low pressure gas pipeline

Pressure testing of equipment and the internal gas pipeline is performed with an air mixture under a pressure of 1000 mm of water. Art. The area to be inspected is from the main valve to the disconnect switch in front of the burners. Testing lasts 1 hour. During this time, a pressure drop of 60 mm of water is allowed. Art.

Pressure testing in an apartment building includes inspection and testing of household equipment.

1. A pressure gauge and any device with a variable volume will be connected to the nozzle of the gas stove. With its help, an overpressure of up to 5 kPa is created.
2. Open the valve of the tested burner and fill the reservoir with gas.
3. Close the valve on the gas pipe. Gas is squeezed out of the container to create pressure.
4. The burner valve is closed and the tightness is checked with a manovacuum meter: in 5 minutes, the pressure can drop by no more than 0.3 kPa.
5. If the head drops faster, there is a leak. It is found by applying soapy water to joints and threaded joints. After a leak is found, turn the valve on the burner so that the gas pressure on it drops. Then one of the burners is ignited, the gas is carefully squeezed out of the container and the pressure gauge and the device are disconnected.

The test results are entered by the selection committee into the acceptance certificate.

Objects of pressure testing and algorithm of actions

The air test is carried out in the following cases:

• when installing internal and external gas pipelines, equipment, tanks, filling gas tanks;
• after assembly of gas control points and installations;
• after replacing or repairing gas pipes or devices, as well as connecting new ones.

Pneumatic testing of a gas pipeline for tightness and strength is strictly regulated.

1. The studied section of the gas line is turned off. To do this, close the high-pressure tap.Twist the low valve and install plugs at the ends of the circuit.
2. If a break in the flange connections is detected, jumpers are installed.
3. Connect a rubber-fabric sleeve and release the gas to a safe place. Burn whenever possible.
4. The pipe is purged and a pressure gauge and a compressor are mounted. If the area is small, you can get by with a hand pump.
5. The compressor pumps air at the required pressure. Then the tests begin.

During pressure testing, all shut-off devices on the air supply must be closed.

Gas pipeline pressure test results

The tests are considered satisfactory if the pressure in the area remains stable. The norms are as follows:

• in the external gas pipeline, the change in pressure leaves no more than 10 daPa per hour;
• in the internal, the decrease in the indicator does not exceed 60 daPa / h;
• in the internal gas pipeline of houses, a pressure drop of no more than 20 da Pa is allowed in 5 minutes;
• in liquefied gas tanks, the parameter can change by no more than 0.3 MPa per 1 hour.

If the pressure changes above the norm, the result of the pressure test is considered unsatisfactory. In this case, the area is inspected to detect a leak and the damage is repaired. The control pressure test is repeated.

If the readings meet the standards, the site is taken into operation.

Basic safety provisions when starting gas into the system

When starting up and checking the circuit, the following safety rules must be followed:

• The gas is started at a certain flow rate. The feed speed is maintained at the level of 15–25 m / s.
• When filling, the pressure should be kept at around 0.1 MPa.
• All participants in the installation and inspection of the gas pipeline must wear protective suits, a helmet, and shoes. Workers should have a fully stocked first aid kit with them.
• The area where pressure testing is performed is fenced off.

It is strictly forbidden to smoke, use lighters, perform any hot work in the area of ​​gas pipeline pressure testing.