Why Leak Test?

Everything Leaks Air!

Leak testing is crucial in various industries to ensure safety and maintain quality. According to Google search results, "leak testing is the process of checking for leaks in a pressure system to prevent hazardous consequences, product malfunction, and ensure compliance with production standards. The most reliable and common method is pressure testing."

Importance of Leak Testing in Manufacturing

In manufacturing, different methods can be leveraged to test for leaks, but pressure testing stands out for its reliability. A simple way to understand pressure testing is to inflate a balloon. Any drop in pressure, visible through a gauge, would immediately indicate a leak.

Small leaks can lead to significant problems, making it essential to employ a fast and reliable method for leak detection in parts. Even minuscule leaks need to be addressed promptly.

Why Conduct Leak Tests?

Leak testing is conducted for two primary reasons:

1. Safety: Ensuring parts don’t leak is paramount for safety. Leaking parts can lead to accidents, fires, explosions, and extensive damage to people and surroundings.
2. Quality: Quality assurance through leak testing helps avoid product malfunction, costly manufacturing mistakes, and impaired customer relations.

Testing an engine block for leaks is as critical as ensuring that each blood bag does not leak. Diverse parts, whether large or small, rugged or delicate, simple or intricate, must be checked for leaks.

Applications of Leak Testing

Uson manufactures a variety of leak testing equipment for applications in medical, automotive, industrial, and packaging sectors. We specialize in partnering with manufacturers to design leak testing systems optimized for their manufacturing processes.

For more insight into Hot Tack Testing of Flexible Packings, testing is vital not only in maintaining the structural integrity of systems but also in enhancing the safety and quality of production processes.

Part 6: Pressure and Leak Testing

The primary reason for pressure testing is to confirm the integrity of a pressure system. Hydrostatic pressure testing can also provide local relief of mechanical stresses. Pressure testing new systems or components poses potential hazards due to the stored energy of the pressurized fluid; hence, only trained and qualified personnel should supervise pressure tests. Testing may involve internal pressure, external (i.e., vacuum) pressure, or both.

Requirements and Standards

All new construction pressure systems must be tested as per the Code of Record and documented appropriately. The inspector, in agreement with the System Owner and system Design Authority (DA), may forgo witnessing the final system pressure test but must still document the test (Form PS-7).

The Codes and Standards applicable to pressure or leak tests include:

• ASME B31 Piping Codes
• ASME BPVC
• ASME PCC2
• NBIC (NB-23)

Procedures must follow ASME B31.3 § 345, ASME BPVC D1 UG-99 through UG-102, or other applicable Code Sections. Types of pressure tests include:

• Hydrostatic (fluid is liquid)
• Pneumatic (fluid is a gas)
• Hydro-pneumatic (fluid is a combination of gas and liquid)

Pneumatic and hydro-pneumatic tests should not be performed on components susceptible to brittle fracture, such as glass, PVC, CPVC, or cast iron.

Stored Energy and Safety

The stored mechanical energy of the test volume should be calculated using methods such as Ideal Gas Laws, Brode’s equation, or Baker’s equation, as deemed suitable by the DA or test engineer. If the system fluid is reactive, flammable, or explosive, its chemical potential energy must also be determined. The sum of chemical and mechanical stored energies represents the total stored energy of a pressurized fluid.

The minimum safe distance between personnel and tested equipment should be determined by calculating the stored energy equivalent in TNT and using a scaled consequence factor.

Process Steps for Leak/Pressure Tests

1. Determine the scope and nature of the pressure test in accordance with Code and Lab requirements.
2. Calculate the stored energy of the test.
3. Prepare an Operational Safety Procedure (OSP) or Temporary Operational Safety Procedure (TOSP) if necessary. This should detail:
• Roles and Responsibilities
• Rationale for test type selection
• Stored energy of the test
• Qualifications of personnel conducting the test
• Personnel and equipment protection measures
• System description and tested components
• Test instrumentation schematic
• Possible Oxygen Deficiency Hazard (ODH) hazards
• Procedure for performing the test
• Inspection procedures pre, during, and post-test
• Recovery procedures, if applicable
4. Complete the pressure test form (Form PS-7) by the test engineer, test technician, and if applicable, Owner’s Inspector.
5. Ensure the pressure test form is filed in the Pressure Systems database.

Conversion to Equivalent Mass of TNT

The stored mechanical energy may be converted to an equivalent mass of TNT using the following equation:

TNT = E / 1488617

Where:

• E = stored energy of test (ft-lbf)
• TNT = equivalent amount of TNT (lb)

For more information, please visit Gross Leak Tester.