Nitrogen is used in many industries for leak testing. While it is best known for its use in oil industry production for pressure testing of pipelines and sealed vessels， nitrogen is also popular for leak testing in a range of other industries.

There are several advantages to using nitrogen for leak testing. Nitrogen is inert， odorless， and has a low water content， so it does not have many of the problems associated with using air or water for pressure testing.

In addition， nitrogen is ideal for testing in a variety of locations thanks to portable nitrogen generators (PSA nitrogen generators， nitrogen equipment). These units can produce unlimited amounts of nitrogen where it is needed conveniently and economically.

What is a leak test?

A nitrogen leak test procedure is performed to verify the integrity of the pathway through which it flows. This analysis process is performed on pipelines， storage containers and any other pipelines that carry industrial products. Leak testing using nitrogen can be performed prior to the first operational use of the equipment， or at intervals during daily operation.

Leak detection allows industrial equipment operators to safely transport their products while minimizing the risk to personnel from hazardous chemicals transported through production channels. Examples include testing for leaks in piping， refrigeration systems， checking the tightness of food processing facilities， and ensuring the functionality of newly installed fire sprinkler systems.

Why use nitrogen for leak testing?

Nitrogen has many physical properties that make it uniquely suited for leak testing. It is an inert gas that is virtually unresponsive under normal industrial conditions. Gaseous nitrogen also prevents oxidation/corrosion reactions by eliminating water vapor and oxygen from sensitive equipment.

These reasons make leak testing with nitrogen a superior choice over other methods， such as hydrostatic pressure testing.

How to Perform Nitrogen Leak Testing

Nitrogen leak testing follows a sequential set of steps， depending on the nature of the equipment to be inspected. The process typically involves introducing a steady stream of gaseous nitrogen under increasing pressure into a selected pipe， vessel or vat.

Various mechanical and automated methods can then be used to identify defects in the industrial component being analyzed.

What is a pressure test?

Pressure testing is an important aspect of pipeline testing prior to first use， as it determines whether or not it is fully ready for use. During the pressure testing activity， various parameters are analyzed， including the following

Maximum allowable pipeline capacity

Leakage check

Stability of joints

Pressure rating

Reliability of components

After careful consideration of the above parameters， operators will be able to determine whether their newly assembled pipelines will be able to withstand the rigorous requirements of full load operation.

In newly assembled pipeline networks， several pressure tests may be required to detect and correct defects before they can be granted full operational status. Suzhou XITE Gases has a pipe filling calculator that makes it easy to calculate the gas volume during a pressure test.

Why use nitrogen for pressure testing?

The reasons surrounding the use of nitrogen as a driving force for pressure testing are due to its favorable physical and chemical properties. First， nitrogen is an odorless， colorless and chemically inert gas， which means there is no reaction with the equipment components undergoing the pressure test.

Moreover， nitrogen does not expose sensitive equipment to the accumulation of moisture， corrosion and particulate contaminants; instead， gaseous nitrogen used to perform pressure tests has the added benefit of displacing oxygen， moisture and particulate contaminants from the equipment under test.

Finally， pressure testing with nitrogen greatly reduces the risk of spontaneous combustion accidents， making the testing process safer for all involved.

If you are looking for a pressure vessel or pipeline hydrostatic testing company， then look no further! Suzhou XITE Gas has the solution you need.

How to pressure test with nitrogen

The specifics of a leak test depend on the vessel or system being tested， but there are general guidelines. In order to prepare a system component for testing， it needs to be isolated from other parts of the system that are not included in the test. This may require temporarily securing any pressure valves and closing valves that connect the piping or vessel to upstream or downstream equipment.

To begin testing a component， a nitrogen tank or on-site nitrogen generator (PSA nitrogen machine， nitrogen equipment) will be connected to the component. Nitrogen will be released， causing the pressure within the test part to rise to a low pressure while forcing any air， debris or other material away from the part. This will remove any contaminants from the system and check for leaks.

A routine pressure test consists of two phases.

Low pressure test

High Pressure Test

Low Pressure Test

This low pressure test will typically be performed at no more than 25% of the component's rated operating pressure. The pressure will be held at this level for a sufficient period of time to ensure that the component can successfully hold pressure without leakage.

If the low pressure test is successful， the pressure will be gradually increased to test the system's ability to maintain its integrity at higher pressures.

High Pressure Testing

The pressure will eventually be raised to the rated operating pressure. The actual limiting pressure required to complete the test will depend on the industry and the regulations governing leak testing.

To find the leak， a soap solution may be used. The leaking pressurized hydrogen will cause the soap solution to bubble， thus identifying the location of the leak. Once any leaks are found at a given pressure level， the part will need to be depressurized and then repaired. Once repairs are complete， the pressure test can be started from scratch.

After the pressure test is completed， the nitrogen pressure is reduced. A small amount of nitrogen is usually left in the line or vessel to protect it until it is filled with the substance for which it was designed. The nitrogen continues to protect the interior from damage or risk that might result from exposure to air.

Often， leak testing must be performed at a remote facility or field location. For pipeline maintenance companies and other entities that frequently perform pressure testing at different locations， it is often more economical to purchase portable nitrogen generators (PSA nitrogen generators， nitrogen equipment).

For companies that do not routinely perform pipeline or vessel cleaning， the best option may be to purchase a nitrogen generator (PSA nitrogen machine， nitrogen equipment) using Suzhou XITE Gases. Suzhou XITE Gases can visit your nitrogen generator (PSA nitrogen machine， nitrogen equipment) for maintenance when needed.

Contact XITE Gas today to learn more about using nitrogen generators (PSA nitrogen generators， nitrogen equipment) for leak testing and cleaning of piping and vessels.

How to detect nitrogen

There are several ways to check for nitrogen leaks. In a pressure test， the pressure is raised to the desired level and the area being tested is then wrapped in plastic sheeting. An oxygen sensor can then be inserted through a hole in the plastic sheeting. If the oxygen level reaches below 20%， then a leak can be confirmed.

This method of testing nitrogen works best when the goal is to perform a pressure check on a smaller area， such as a specific flange or fitting after a repair， or after adding a new connection to an existing system.

Commercial nitrogen (N2) detectors can be purchased. These instruments are already in use in the oil and gas industry and are becoming more common in other industries as the use of nitrogen continues to increase. In industry， nitrogen is used in food processing and packaging， electronics， food and pharmaceuticals.

Metalworking， refrigeration and industrial painting facilities use large amounts of nitrogen in their production processes. In less industrial environments， nitrogen is used in commercial and residential buildings to protect their fire suppression lines and sprinkler heads from moisture damage. The food service industry is increasingly using liquid nitrogen to quickly freeze foods.

Typically， nitrogen leak detectors are portable， handheld devices. This allows them to be moved to the location of any suspected leak. Some nitrogen leak detectors are designed to be set up to test for a variety of different gases， making the device even more versatile.

Nitrogen is inert， so the risk of a leak is minimal， but the presence of higher levels of nitrogen can be used to identify a leak. Finding the exact location of a leak may require isolating and testing various parts of the system to narrow down the location of the leak. Afterwards， one of the nitrogen leak testing methods can be used to find the exact location of the leak so that repairs can be completed. After the repair， any areas with seals， valves or welds should be rechecked to ensure there are no additional leaks.