Hydraulic tests are carried out in accordance with SNiP. After their completion, a report is drawn up indicating the operability of the system.

They are performed on different stages operation of communications. Test parameters are calculated for each system separately, depending on its type.

Contents of the article

Why and when to carry out hydraulic tests?

Hydraulic testing is a type non-destructive testing which is carried out to check the strength and density pipeline systems. All operating equipment is subjected to it at different stages of operation.

In general, three cases can be distinguished in which tests must be carried out without fail, regardless of the purpose of the pipeline:

• after finishing production process for the production of equipment or parts of the pipeline system;
• after completion of pipeline installation work;
• during operation of the equipment.

Tests hydraulically is an important procedure that confirms or refutes the reliability of the operating pressure system. This is necessary to prevent accidents on highways and preserve the health of citizens.

The procedure for hydraulic testing of pipelines is being carried out in extreme conditions. The pressure under which it passes is called the test pressure. It is higher than usual operating pressure 1.25-1.5 times.

Features of hydraulic tests

Test pressure is supplied to the pipeline system smoothly and slowly, so as not to provoke water hammer and accidents. The pressure value is determined not by eye, but by a special formula, but in practice, as a rule, it is 25% more than the working pressure.

The water supply force is controlled on pressure gauges and measurement channels. According to SNiP, jumps in indicators are allowed, since it is possible to quickly measure the temperature of the liquid in a pipeline vessel. When filling it, be sure to monitor the accumulation of gas on the different areas systems.

This possibility should be excluded at the initial stage.

After filling the pipeline, the so-called holding time begins - the period during which the equipment under test is under high blood pressure. It is important to ensure that it is at the same level during exposure. After its completion, the pressure is minimized to operating condition.

No one should be near the pipeline while the test is being carried out.

The personnel serving it must wait in safe place, since checking the functionality of the system can be explosive. After the process is completed, the results obtained are assessed in accordance with SNiP. The pipeline is inspected for metal explosions and deformations.

Hydraulic test parameters

When checking the quality of a pipeline, it is necessary to determine the indicators of the following work parameters:

1. Pressure.
2. Temperatures.
3. Holding time.

The lower limit of the test pressure is calculated using the following formula: Ph = KhP. The upper limit should not exceed the sum of the total membrane and bending stresses, which will reach 1.7 [δ]Th. The formula is deciphered as follows:

• P – design pressure, the parameters of which are provided by the manufacturer, or operating pressure if tests are carried out after installation;
• [δ]Th – rated voltage that is allowed at test temperature Th;
• [δ]T – permissible stress at design temperature T;
• Kh – conditional coefficient taking different meaning For different objects. When checking pipelines, it is equal to 1.25.

The water temperature should not fall below 5˚C and not rise above 40˚C. The only exceptions are those cases when the temperature of the hydraulic component is indicated in the technical specifications of the object under study. Be that as it may, the air temperature during the test should not fall below the same 5˚C.

The holding time must be specified in the design documentation for the facility. It should not be less than 5 minutes. If exact parameters are not provided, then the holding time is calculated based on the thickness of the pipeline walls. For example, with a thickness of up to 50 mm, a pressure test lasts at least 10 minutes, with a thickness over 100 mm - at least 30 minutes.

Testing of fire hydrants and water supply lines

A hydrant is equipment responsible for quickly eliminating fire ignitions, so it must always be in working order. the main task fire hydrants - provide optimal quantity water to fight a fire at its initial stage.

Pressure pipelines are checked in accordance with SNiP V III-3-81.

Pipes made of cast iron and asbestos are tested with a pipeline length of no more than 1 km at a time. Polyethylene water supply lines are checked in sections of 0.5 km. All other water supply systems are checked in sections of no more than 1 km. The holding time for metal water supply pipes must be at least 10 m, for polyethylene pipes - at least 30 m.

Heating system testing

Heating networks are checked immediately after their installation is completed. Heating systems are filled with water through the return pipeline, that is, from the bottom up.

With this method, liquid and air flow in the same direction, which, according to the laws of physics, promotes the removal of air masses from the system. Discharge occurs in one way: through outlet devices, a tank or heating system plungers.

If heating networks are filled too quickly, air pockets may occur due to the risers filling with water faster than the heating devices of the heating systems. pass under lower value working pressure is 100 kilo Pascal and test pressure is 300 kilo Pascal.

Heating networks are checked only when the boiler and expansion tank are disconnected.

Heating systems are not monitored winter time. If they have worked without breakdowns for up to about three months, then the acceptance of heating networks into operation can be carried out without hydraulic tests. When checking closed systems heating, control work must be carried out before the furrows are closed. If you plan to insulate heating networks, then do so before installing it.

According to SNiP, after testing heating systems, they are washed, and a coupling with a cross-section of 60 to 80 mm2 is mounted at their lowest point. Water drains through it. Flushing of heating networks carried out with cold water several times until it becomes transparent. Approval of heating systems occurs if within 5 minutes the test pressure in the pipeline does not change by more than 20 kiloPascal.

Hydraulic testing of heating and water supply systems (video)

Hydraulic testing of heating networks and water supply systems

After completion of hydraulic tests of heating systems in accordance with SNiP, a hydraulic test report of heating networks and water supply systems is drawn up, indicating the compliance of the pipeline parameters.

According to SNiP, its form contains the following information:

• the title of the position of the head of the enterprise providing maintenance of heating networks;
• his signature and initials, as well as the date of inspection;
• information about the chairman of the commission, as well as its members;
• information on the parameters of heating networks: length, name, etc.;
• conclusions about the control, conclusion of the commission.

Adjustment of the characteristics of heating lines is carried out by SNiP 3.05.03-85. According to the specified SNiP it the rules apply to all highways, which transport water at temperatures up to 220˚C and steam at temperatures up to 440˚C.

To document the completion of hydraulic tests of the water supply system, a report is drawn up for the external water supply system in accordance with SNiP 3.05.01-85. According to SNiP, the act contains the following information:

• name of the system;
• name of the technical supervision organization;
• data on the test pressure and test time;
• pressure drop data;
• presence or absence of signs of damage to the pipeline;
• date of inspection;
• commission withdrawal.

The report is certified by a representative of the supervisory organization.

From the editor: Until now, experts cannot come to unanimous opinion on the issue of conducting hydraulic tests of heating networks. This question repeatedly raised on the pages of the NT magazine (in particular, see NT: No. 6, 2001; No. 8, 2007; No. 7, 2008). To develop the topic, we invite you to read another opinion on this issue in the article below.

Hydraulic testing of heating networks - it's time to think about it!

A.I. Kapitanov, Honorary Mechanical Engineer of Russia,
chief project engineer of ReMoNa LLC, Kolomna, Moscow region

The essence of the proposed method

In Russian conditions (with quality regulation heat supply systems) during the heating season, the water temperature in heating networks, depending on the outside air temperature, changes more than 40 times, i.e. heating network In winter they resemble accordion bellows: sometimes they separate, sometimes they come together.

Cyclic extension of the length of heating network pipelines in heating season range from 10 mm or more. The stresses created in this case cannot be compared with the elongations and stresses in heating networks during tests for strength and density, which, according to clause 6.2.13 of the Rules technical operation thermal power plants" (approved by Order of the Ministry of Energy of the Russian Federation dated March 24, 2003 No. 115) are carried out no later than two weeks after completion heating season.

Thermal power engineers conscientiously carry out the specified test procedure, detect defects in the pipes, fix them in the summer, and before the start of the heating season cheerfully report to all authorities about the readiness of heating networks for the coming winter.

But with the onset of the next heating season, again sleepless nights, again rushes to eliminate leaks in heating networks, and so on ad infinitum.

The author of the article, being the head of the energy service of a reputable enterprise, experienced all these delights of life and, completely exhausted, gave the command to conduct cyclic temperature tests of heating networks at the end of the heating season, in other words, to simulate their behavior in the upcoming heating season.

As a result of the tests, instead of 3-4 traditional leaks, 34 leaks were identified.

During the summer, without emergency work, these leaks were fixed as planned, and the coming winter was by and large survived without the slightest disruption in heat supply to consumers. Further, the experience gained was practiced annually.

conclusions

It’s time to stop flattering yourself with the thought: “At the end of the heating season, I carried out hydraulic tests of heating networks. Over the summer, I fixed 3-4 identified leaks and everything will be fine for me in the upcoming heating season.” This is obvious self-deception!

Necessary:

1. At the end of the heating season, prepare for at least one work shift 5-6 times sharply (by 30-40 O C) at operating pressure and water circulation, raise and lower the temperature of the water in the heating network.

2. Despite leaks, emergencyly recharge the heating network, turn it on and off hot water boilers(steam-water heaters) until the pressure drop in the heating network stabilizes (this will indicate that new leaks do not appear).

3. At the same time, bypass the heating network and record leaks.

The implementation of this seemingly insignificant event will allow:

■ provide in winter period uninterrupted heat supply to consumers;

■ prevent unproductive losses of thermal energy;

■ improve the social climate in the team servicing boiler plants and heating networks.

TYPICAL TECHNOLOGICAL CARD (TTK)

TESTING FOR STRENGTH AND TIGHTNESS OF EXTERNAL HEATING NETWORKS

I. SCOPE OF APPLICATION

I. SCOPE OF APPLICATION

1.1. A standard technological map (hereinafter referred to as TTK) is a comprehensive organizational and technological document developed on the basis of methods scientific organization labor to perform the technological process and the determining composition of production operations using the most modern means mechanization and methods of performing work using a specific technology. The TTK is intended for use in the development of the Work Performance Project (WPP) by construction departments and is its integral part in accordance with MDS 12-81.2007.

1.2. This TTK provides instructions on the organization and technology of work to test the strength and tightness of external heating networks, defines the composition of production operations, requirements for quality control and acceptance of work, planned labor intensity of work, labor, production and material resources, measures for industrial safety and labor protection.

1.3. The regulatory framework for the development of technological maps is:

- standard drawings;

- building codes and regulations (SNiP, SN, SP);

- factory instructions and technical specifications(THAT);

- norms and prices for construction installation work s (GESN-2001 ENiR);

- production standards for material consumption (NPRM);

- local progressive norms and prices, norms of labor costs, norms of consumption of material and technical resources.

1.4. The purpose of creating the TC is to describe solutions for the organization and technology of work on testing the strength and tightness of external heating networks in order to ensure their High Quality, and:

- reducing the cost of work;

- reduction of construction duration;

- ensuring the safety of work performed;

- organizing rhythmic work;

- rational use labor resources and cars;

- unification of technological solutions.

1.5. On the basis of the TTK, as part of the PPR (as mandatory components of the Work Project), Workers are being developed technological maps(RTK) for execution individual species works on testing the strength and tightness of external heating networks.

The design features of their implementation are decided in each specific case by the Working Design. The composition and degree of detail of materials developed in the RTK are established by the relevant contracting construction organization, based on the specifics and volume of work performed.

The RTK is reviewed and approved as part of the PPR by the head of the General Contracting Construction Organization.

1.6. The TTK can be tied to a specific facility and construction conditions. This process consists of clarifying the scope of work, means of mechanization, and the need for labor and material and technical resources.

The procedure for linking the TTC to local conditions:

- reviewing map materials and selecting the desired option;

- checking the compliance of the initial data (amount of work, time standards, brands and types of mechanisms, building materials used, composition of the worker group) with the accepted option;

- adjustment of the scope of work in accordance with the chosen option for the production of work and a specific design solution;

- recalculation of calculations, technical and economic indicators, requirements for machines, mechanisms, tools and material and technical resources in relation to the chosen option;

- design of the graphic part with specific reference to mechanisms, equipment and devices in accordance with their actual dimensions.

1.7. A standard flow chart has been developed for engineering and technical workers (work managers, foremen, foremen) and workers performing work in the third temperature zone, in order to familiarize (train) them with the rules for carrying out work on testing the strength and tightness of external heating networks with using the most modern means of mechanization, advanced designs and materials, and methods of performing work.

The technological map has been developed for the following scope of work:

Total pipeline length	- =1000 m.
Test pressure Р=1.25Р	- R =1.6 MPa.

II. GENERAL PROVISIONS

2.1. The technological map has been developed for a set of works to test the strength and tightness of external heating networks.

2.2. Work on testing the strength and tightness of external heating networks is carried out in one shift, the duration of working hours during the shift is:

2.3. The scope of work performed when testing the strength and tightness of external heating networks includes:

- preparing the working whip for preliminary testing;

- piping the filling and crimping units and testing them;

- filling the pipeline section to be tested with water;

- pressure rise to test pressure;

- testing the working whip for strength;

- checking the working lash for leaks;

- switching shut-off valves;

- control of water pressure and temperature;

- final (acceptance) tests of the pipeline.

2.4. The technological map provides for the work to be carried out by a complex mechanized unit consisting of: self-priming centrifugal pump S-245 "Andijan" designed for pumping water, capacity 100 m/hour, self-priming height h=5.0 m, diesel engine power T-62-1 N=13 hp, overall dimensions 1800x930x1225 mm, weight P=800 kg, diameter of suction and pressure hoses 100 mm; mobile diesel compressor Atlas Copco XAS 97 (P=7 bar productivity 5.3 m/min).

Fig.1. Self-priming pump S-245

Fig.2. Compressor Atlas Copco XAS 97

2.5. To test the strength and tightness of external heating networks, the following materials are used as the main materials: steel pipes with bitumen-perlite insulation with a diameter of up to 426 mm according to GOST 3262-75 *); coated electrodes metal for manual arc welding type E42 meeting the requirements of GOST 9467-75 *.

2.6. Work on preliminary testing of the strength and tightness of external heating networks should be carried out in accordance with the requirements of the following regulatory documents:

- SP 48.13330.2011. "SNiP 12-01-2004 Organization of construction. Updated edition" ;

- SNiP 41-02-2003 Heat networks;

- SNiP 41-03-2003. Thermal insulation of equipment and pipelines;

- SNiP 3.05.03-85. Heating network;

- STO NOSTROY 2.33.14-2011. Organization construction production. General provisions;

- STO NOSTROY 2.33.51-2011. Organization of construction production. Preparation and execution of construction and installation works;

- SNiP 12-03-2001. Occupational safety in construction. Part 1. General requirements;

- SNiP 12-04-2002. Occupational safety in construction. Part 2. Construction production;

- RD 11-02-2006. Requirements for the composition and order of operation executive documentation during construction, reconstruction, major renovation capital construction projects and requirements for inspection reports of works, structures, sections of engineering and technical support networks;

- RD 11-05-2007. The procedure for maintaining a general and (or) special log of work performed during construction, reconstruction, and major repairs of capital construction projects.

III. ORGANIZATION AND TECHNOLOGY OF WORK EXECUTION

3.1. In accordance with SP 48.13330.2001 “Construction Organization”, before the start of construction and installation work at the site, the Contractor is obliged to in the prescribed manner receive from the Customer project documentation and permission to carry out construction and installation work. Carrying out work without permission is prohibited.

3.2. Before starting work on preliminary testing for the strength and tightness of external heating networks, it is necessary to carry out a set of organizational and technical measures, including:

- develop RTK or PPR for testing heating networks;

- appoint persons responsible for the safe performance of work, as well as their control and quality of execution;

- conduct safety training for team members;

- install temporary inventory household premises for storing building materials, tools, equipment, heating workers, eating, drying and storing work clothes, bathrooms, etc.;

- provide the site with working documentation approved for work;

- prepare machines, mechanisms and equipment for work and deliver them to the site;

- provide workers manual machines, tools and personal protective equipment;

- provide construction site fire-fighting equipment and alarm systems;

- prepare places for storing building materials, products and structures;

- fence the construction site and put up warning signs illuminated at night;

- provide communication for operational dispatch control of work;

- deliver to the work area necessary materials, devices, equipment, tools and means for safe work;

- try it out construction machines, means of mechanization of work and equipment according to the nomenclature provided for by the RTK or PPR;

- draw up an act of readiness of the facility for work;

- obtain permission from the Customer’s technical supervision to begin work (clause 4.1.3.2 RD 08-296-99).

3.4. General instructions

3.4.1. Hydraulic tests

3.4.1.1. Hydraulic testing of pipelines should be carried out in compliance with the following basic requirements:

- test pressure must be provided at the top point (mark) of the pipelines;

- the water temperature during testing must be no lower than 5°C;

- at negative temperature outside air, the pipeline must be filled with water with a temperature not exceeding 70°C and it must be possible to fill and empty it within 1 hour;

- when gradually filling with water, air must be completely removed from the pipelines through air bleed valves;

- a test pressure equal to the working one is established in the pipeline and maintained for the time necessary to inspect the joints, but not less than 10 minutes and then reduced to the working one;

- at operating pressure, the pipeline must be inspected along its entire length;

- if during the test test pressure no defects or leaks are found, it is brought to the test level (1.25P) and maintained for the time necessary for a thorough inspection, but not less than 10 minutes.

3.4.1.2. The results of hydraulic tests of the pipeline for strength and tightness are considered satisfactory if during the tests:

- there was no pressure drop;

- no signs of rupture, leakage or fogging were found in the welds, as well as leaks in the base metal, flange connections, fittings and other pipeline elements;

- there are no signs of displacement or deformation of the pipeline and fixed supports.

3.4.1.3. Pipeline defects should be repaired after the pressure has been reduced to atmospheric pressure.

3.4.1.4. The technology for correcting defects and the control procedure must be defined in the Working Flow Chart.

3.4.2. Pneumatic tests

3.4.2.1. Pneumatic tests should be carried out for steel pipelines with a working pressure not higher than 1.6 MPa (16 kgf/cm) and a temperature of up to 250°C, installed from pipes and parts tested for strength and tightness (density) by manufacturers in accordance with GOST 3845-75 * (in this case, the factory test pressure for pipes, fittings and other pipeline products and parts must be 20% higher than the test pressure adopted for the installed pipeline).

3.4.2.2. The installation of cast iron fittings (except for valves made of ductile cast iron) is not allowed during testing.

3.4.2.3. Pneumatic testing is carried out in the following sequence:

- clean and purge the pipeline;

- install plugs and pressure gauges;

- connect a compressor to the pipeline;

- smoothly fill the pipeline with air at a speed of no more than 0.3 MPa (3 kgf/cm) per hour;

- at a pressure value equal to 0.3 test, but not more than 0.3 MPa (3 kgf/cm), visually inspect the route [entrance to the security (dangerous) zone, but without descending into the trench]. During the inspection of the route, the pressure rise must be stopped;

- when the test pressure is reached, the pipeline is maintained to equalize the temperature along the length of the pipeline;

- after equalizing the air temperature, the test pressure is maintained for 30 minutes - the test itself;

Conducting hydraulic tests of heating networks needed for testing pipelines, components, seams, for strength and their density. This is done due to the fact that over time, even with good maintenance, the equipment can wear out and, as a result, fail. And to prevent emergency situations, in order to timely find defects that can cause an irreversible process, a number of activities are carried out, consisting of testing and network testing.

Photos of objects

Objects on the map

Video of the company "PROMSTROY"

Watch other videos

One of which is hydraulic, necessary to identify:

• actual water consumption by consumers;
• determination of pipeline hydraulic characteristics;
• to find areas with increased hydraulic resistance;
• testing for strength and tightness.

In what cases is it necessary to carry out hydrotesting?

• Upon completion of pipeline installation work, which was carried out due to the replacement of pipes or the assembly of a new section heating system, before putting it into operation.
• In case of replacement or repair of components of the heating network.
• During scheduled network maintenance, which is carried out with the aim of starting the heating system for the autumn and winter period.

Cost of hydraulic testing of heating networks

What is used to measure pipeline characteristics

When carrying out activities to measure flow rates and pressures, instruments that are metrologically certified are used:

• One of them is a deformation pressure gauge or pressure sensors, which have an accuracy class of at least 0.4. These devices are used to measure pressure.
• When measuring water flow, standard instruments are used that are installed on heat source and with the help of flow meters located in the metering unit. In the absence of one of the listed devices, an ultrasonic flow meter is used, the sensors of which are overhead. The magnitude of its error should be no more than 2.5 percent.

Stages of testing

Activities consist of preparation, direct testing and analysis of indicators obtained as a result of tests.

• The first stage is preparation. During this period, the initial data on the network is clarified and recorded, after which the measurement program is developed and agreed upon. At this stage, preparatory actions are also underway to create testing conditions. This includes:
  • Before starting the process, you need to check whether all work on welding, installation, installation of gaskets in connections, and tightening of these connections has been completed.
  • You also need to check whether all the equipment is in order, the presence and functionality of the air drain valves.
  • Connecting the hydraulic press to the water supply and to the pressure pipe pipeline. Checking the correct connections.
  • Disconnecting the pipeline section where the test will be carried out from equipment that has not yet been fully installed or is already in use.
  • Installation of necessary instruments for testing.
• The second stage is to conduct a test under appropriate conditions. Tests must be carried out in compliance with all requirements regarding temperature regime environment. In case of violation, this may lead to inaccuracy of the received data.
• The necessary conditions:
• The ambient temperature during events must be above zero.
• The temperature of the water used in the test should be from +5 to +40.
• Providing observation platforms for above-ground heating systems.
• Smooth increase in pressure. It should be approximately 40% higher than nominal. To increase it, the use of compressed air is prohibited.
• The test section of the pipeline must be maintained under test pressure for at least 15 minutes.
• Upon completion, the entire site must be carefully inspected and if defects are found, the measures necessary to eliminate them must be taken.
• AND final stage , this is an analysis of the results obtained and the compilation of a table indicating all the parameters. If deviations from the norm are detected, measures are taken to eliminate them, such as:
• Cleaning and flushing of the pipeline.
• Pipeline relocation.
• When serious problems, repairs and elimination of detected defects are carried out.

Upon completion of measures to eliminate the causes of deviations, the tests must be carried out again.

Hydraulic testing of pipelines of heating networks (pressure testing) is carried out with water at a temperature not lower than + 5 ° C. Pipelines and their parts must be subjected to hydraulic testing with a test pressure equal to 1.25 working pressure, but not less than 1.57 MPa (16 kgf/cm 2 ) for supply pipes and 1.18 MPa (12 kgf/cm 2) for return pipes.

According to the Rules for Technical Operation (PTE) of Heating Networks and Heating Points of the Ministry of Housing and Public Utilities of the RSFSR, water heating networks from boiler houses equipped cast iron boilers, are tested at a pressure equal to 1.25 working pressure in the supply manifold, but not less than 0.59 MPa (6 kgf/cm2). Pressure must be measured using two proven pressure gauges with an accuracy class of at least 1.5.

Hydraulic testing of heating networks with duct and channelless gaskets are carried out in two stages (preliminary and final). A preliminary test is done on small areas- up to 1 km, final - when performing all construction and installation work. Both are done after the moving supports are installed and welded, the fixed supports are installed and backfilled, but before the pipes and fittings are covered with thermal insulation. When installing pipelines from seamless pipes, hydraulic testing of pipelines can be carried out after insulating the pipes, but provided that the welded joints are free from insulation, not covered with waterproofing and are located in places accessible for inspection.

If during tests with test pressure no pressure drop is detected, the pressure in the tested section of the pipeline is reduced to the working one and at this pressure the welded joints are tapped with a hammer with a rounded head weighing no more than 1.5 kg with a handle length of no more than 500 mm; blows must be delivered at a distance of at least 150 mm from weld at both sides. The test results are considered satisfactory if the pressure did not drop during the test, and no signs of rupture, leakage or sweating were found in the welded seams of the pipes.

Draining of water after testing or detection of defects should be carried out immediately with final air purging of the emptied heat pipelines, and it should be checked whether there is any water remaining at the lowest points of the pipeline.

Hydraulic testing of individual pipes is carried out in accordance with GOST 3845-75. For hydraulic testing of pipes of small diameters and lengths of sections, manual hydraulic pumps are used, and for large diameters, piston pumps with mechanical and electrical drives are used.

Pneumatic testing of pipelines. According to SNiP III-30-74, testing of pipelines for strength and tightness can be carried out instead of hydraulic testing pneumatically at the discretion of the construction organization (heating network enterprise) if it is difficult to carry out a hydraulic test (winter time, lack of water at the test site, etc.). Pneumatic tests must be carried out in accordance with the rules SP 298-65 of the USSR State Construction Committee. According to the rules, pneumatic testing of heating network pipelines with a coolant temperature above 120 ° C, steam pipelines with a pressure above 0.098 MPa (1 kgf/cm 2) must be carried out with a test pressure equal to the working pressure with a coefficient of 1.25, but not less than 1.57 MPa (16 kgf/cm2) for supply and 0.98 MPa (10 kgf/cm2) for return pipelines.

Considering that in installation conditions it is practically impossible to create such a test pressure, and also that with such a high test pressure with air it would create a great danger for personnel, and in urban conditions and for the population, replacing a hydraulic test with a pneumatic one should be avoided if possible. In the absence of water, it is allowed to carry out preliminary testing of pipelines with air at a pressure of 0.59 MPa (6 kgf/cm2). The pipeline is maintained under this pressure for 30 minutes, then the pressure is reduced to 0.29 MPa (3 kgf/cm2) and the pipelines are inspected. Air leaks are detected by washing the joints, by sound, by odorization or smoke formation of the air in the pipeline. After a preliminary pneumatic test, the final test is carried out hydraulically.