Valve Testing and Inspection in Quality Control Explained

Valve Testing and Inspection in Quality Control Explained

Quality inspections and valve testing play a crucial role in ensuring the reliable operation of fluid systems. Industrial valves are essential components in a multitude of industrial machinery, and even the slightest malfunction can trigger significant disruptions throughout the machine's functionality. Therefore, conducting the appropriate checks to guarantee both safety and efficiency is imperative.

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Testing valves involves various procedures that must adhere to rigorous acceptance criteria and performance standards. In this article, we will outline the essential aspects you need to understand concerning valve inspection procedures and the tests conducted.

What Are the Common Types of Valves?

Valves are available in a wide range of shapes and sizes, dictated by the specific industry or application in which they are utilized.

The most prevalent types of valves include:

1. Butterfly Valve

2. Gate Valve

3. Globe Valve

4. Gray Iron Valve Body

5. Gray Iron Valve Cover

6. Plug Valve

7. Swing Check Valve

The Importance of Valve Testing

Valves must meet specific leakage standards, and additional inspections are typically conducted. It is advisable to perform valve testing and inspections approximately every 12 months to verify that they remain in optimal working condition. This frequency may vary based on the valve's age, condition, and type.

How Do Valve Leakages Happen?

Leakages in valves are a common occurrence and can arise from various factors. Primarily, they may result from fugitive emissions escaping into the atmosphere, or leaks that remain confined within the piping system.

The first scenario can have damaging effects on the environment and pose safety hazards. Valves are significant contributors to fugitive emissions, underscoring the necessity of quality management and rigorous testing protocols.

What Are the Common Causes of Valve Leakages?

Leaks are a prevalent issue across numerous industries, arising from various causes. Common factors contributing to valve leakages include failure to fully close the valve due to obstructions on the valve seat, inadequate actuator travel, or damage to the valve seat itself. Comprehensive testing will help identify all potential issues.

What Are the Common Reasons for Leaks Into the Atmosphere?

Potential leaks into the atmosphere could result from a damaged gasket between the valve body and bonnet, or issues with the stem packing that may be misplaced, worn, or damaged.

What Is Valve Testing?

Valve testing is a critical process employed to assess the condition or functionality of operational valves. A variety of tests and inspections are conducted to ensure valves are safe for use and in proper working condition.

What Are the Valve Testing Procedures?

A standard hydrostatic valve testing procedure typically involves the following steps:

• The valve body is filled with testing fluid at a controlled temperature.

• Pressure is applied for a specified duration, usually at least one minute.

• Leakage is measured across key components of the valve such as the stem, seat, or closure mechanism, using both physical instruments and visual inspection techniques.

• Finally, a thorough visual inspection is conducted to check for any damage incurred during the testing process.

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What Are the Main Valve Leakage Tests?

Here are the most common tests performed to assess valve leakages and their associated valve types:

Valve Seat Leakage Tests

This procedure includes placing the valve under pressure and measuring the leakage on the opposite side of the valve. The test pressures are often prescribed by the American Society of Mechanical Engineers (ASME) B16.34.

Back Seat Tests

Commonly performed on valves equipped with backseat elements, such as gate and globe valves, these tests are conducted per established protocols, often requiring the valve to be opened while the packing gland is either loose or removed.

Valve Closure Tests

This test is generally performed on valves that are used in either fully closed or fully open applications. This category includes stop valves, globe valves, plug valves, and ball valves.

Shell Leakage Tests

This test identifies the presence of water or other fluids within the valve casing by applying pressure for a designated period, usually exceeding one minute, and checking for any leaks. It is executed on valves like check, stop, and isolation types.

The Types of Valve Testing Standards

The following provides an overview of several prominent valve testing standards:

• API 598: Valve Inspection and Test

• API 527: Seat Tightness of Pressure Relief Valves

• ASME B16.34: Valves — Flanged, Threaded, and Welding End

• ASME PTC 25: Pressure Relief Devices

• FCI 70-2: Control Valve Seat Leakage

• ISA-S75: Hydrostatic Testing of Control Valves

• ISO: Industrial Valves, Pressure Testing of Valves

• MSS SP61: Hydrostatic Testing of Steel Valves

• MSS SP70: Cast Iron Gate Valves, Flanged, and Threaded Ends

• MSS SP71: Cast Iron Swing Check Valves, Flanged, and Threaded Ends

• MSS SP78: Cast Iron Plug Valves, Flanged, and Threaded End

• MSS SP80: Bronze Gate, Globe, Angle, and Check Valves

• MSS SP85: Cast Iron Globe and Angle Valves

All relevant documentation can be obtained through a third-party quality management company, such as HQTS. Our qualified inspectors are prepared to conduct testing on your valves, ensuring that only the highest quality products leave your facility, leading to satisfied customers and a healthier environment.

Conclusion: Valve Testing Procedures in Quality Control

The quality control process for valves is fundamental to the effectiveness of any manufacturing operation. Valves play a vital role in numerous industries, and even minor malfunctions can have adverse impacts on overall operations. The valve inspection process guarantees that the valves are defect-free and conform to established quality standards.

With various valve testing procedures available, HQTS brings over 25 years of expertise in quality management, including assurance and control. As a global company, we can facilitate valve testing in diverse regions. Contact us to schedule your valve test today!

We proudly serve as the leading Test Bench Valve supplier worldwide. Our company serves as your comprehensive resource for all your valve testing needs, supported by a team of specialists dedicated to helping you find the right products.