Hydraulic Piping Pressure Test Standard

Hydraulic tube pressure test refers to the method of testing and verifying pipeline connections, valves, pipes and other components during the installation, maintenance and improvement of hydraulic tubes.

Hydraulic tube pressure test is a key link to ensure the safe operation of hydraulic tubes. Its purpose is to check the sealing performance of the pipeline and its stability under actual working conditions. According to the different test purposes, hydraulic tube pressure tests are mainly divided into two categories: strength test and tightness test.

1. Strength test: verify the ultimate bearing capacity of pipelines and accessories. For pipelines made of seamless pipes, carbon steel pipes and other materials, the strength test is particularly important.

2. Sealing test: detect the leakage of the system under continuous pressure, which is crucial to prevent leakage in the hydraulic system and ensure its normal operation.

Technical specifications for pressure test of hydraulic tubes

1. Pressure parameter standards

Strength test pressure: 1.5 times the design pressure (ASME B31.3 Standard)

Seal test pressure: not less than 1.25 times the working pressure

Pressure fluctuation coefficients should be considered for pipelines in special environments (±10% safety redundancy is recommended)

2. Principles for medium selection

Priority sequence:

① Water (add rust inhibitor, suitable for 90% of scenarios)

② Hydraulic oil (applicable to precision systems)

③ Nitrogen (special gas system, explosion-proof devices are required)

*Oxygen and other combustion-supporting gases are prohibited

2. Temperature Control Requirements

Medium temperature: controlled within the range of ±5℃ of ambient temperature

Metallic pipelines: test temperature should be 20℃ or more below the brittle transition temperature of the material

Non-metallic pipelines: set the upper temperature limit according to the Tg value of the material

Standards for hydraulic tube pressure test

1. Test Methods

Hydraulic tube pressure tests can be conducted using static and dynamic methods. Static tests are generally used for testing small-diameter, low-pressure pipelines, while dynamic tests are used for testing large-diameter, high-pressure pipelines. For some large OCTG pipes, dynamic test methods are usually used due to their large diameter and high pressure.

2. Test equipment

The hydraulic tube pressure test requires the use of test equipment such as pressure gauges and pressure gauges, among which the pressure gauge is one of the most commonly used test equipment. Pressure gauges are divided into mechanical and electronic types. Mechanical pressure gauges have lower accuracy, while electronic pressure gauges have higher accuracy, but the price is also correspondingly more expensive.

3. Test parameters

The hydraulic tube pressure test needs to determine the test parameters based on factors such as the use environment and use requirements of the pipeline. The test parameters include test pressure, test time, test temperature, etc., among which test pressure is one of the most critical test parameters.

Specific regulations for hydraulic tube pressure test

1. Pressure grade classification

Depending on the pressure grade, the standards for hydraulic tube pressure test are also different. Pipes of each pressure grade need to be tested in accordance with the corresponding regulations to ensure the safety performance of the pipeline.

2. Test pressure medium

Common test pressure media include water, nitrogen and air. These media should have good heat transfer performance, flow performance and stability to ensure the reliability of the test results.

3. Test pressure temperature

The test pressure temperature should be close to the working temperature of the pipeline to simulate the pipeline performance under actual working conditions. For example, for boiler tubes working in some high-temperature environments, the test temperature should be close to the actual working temperature to more accurately detect the performance of the pipeline.

4. Test pressure duration

The test pressure duration is usually determined based on factors such as pipeline diameter, material and design pressure, and is generally between 10 minutes and 30 minutes.

5. Determination of test pressure results

There are two main criteria for determining whether the hydraulic tube pressure test is qualified: one is that the pressure drop does not exceed the specified value; the other is that there is no leakage during the test. Only when these two conditions are met at the same time can the test be deemed qualified.

Precautions for hydraulic tube pressure test

When conducting a hydraulic tube pressure test, the following points should be noted:

1. The test equipment needs to be calibrated before the test to ensure its precision and accuracy.

2. The test equipment needs to be monitored and inspected during the test to ensure its normal operation.

3. During the test, the test standard must be strictly followed and the test parameters must not be changed at will.

4. After the test, the test equipment needs to be cleaned and maintained to ensure its long-term reliable use.

Summary

In short, the correct implementation of the hydraulic tube pressure test standard is crucial to ensure the safe and stable operation of the hydraulic system. Relevant personnel should strictly follow the standard to perform the test operation to ensure the safety performance and service life of the pipeline.

Read more: Joint Models of American Seamless Hydraulic Piping or Difference between seamless pipe and seam pipe