ASME B16.48 ASTM A182 F316L Stainless Steel Spectacle Blind Flange Figure-8 Blanks

ASTM A182 F316L Stainless Steel Spectacle Blind Flange Figure-8 Blanks


A spectacle blind flange (figure-8 blank) is composed of two separate metal discs that are welded together at the center. One disc is solid, known as the blind side, and the other disc has a circular opening, known as the spectacle side. The blind side prevents fluid flow while the spectacle side allows flow through the opening when aligned with the pipeline. Blind spectacle flanges are commonly used for maintenance, repair, and testing purposes. By rotating the spectacle blind, operators can isolate a section of the pipeline for repair or maintenance without needing to drain the entire system.

ASTM A182 F316L SS Blind Spectacle Flange Equivalent Grades

Forged and Plate Flanges

SS 316L Flange Standards / Types And Pressure Class

The main purpose of using a blind spectacle flange is to temporarily block off a pipeline or create a leak-proof seal. Here are some specific purposes and benefits of using a blind spectacle flange:

1. Maintenance and Repair: The blind spectacle flange allows operators to isolate a specific section of the pipeline for maintenance or repair work without shutting down the entire system. This eliminates the need to drain the entire system, saving time, effort, and resources.

2. Pressure Testing: Blind spectacle flanges are commonly employed during pressure testing of pipelines or equipment. By closing off a certain portion of the system, operators can accurately test the pressure and integrity of that specific section.

3. System Integrity: The blind side of the spectacle flange provides a secure, leak-proof seal when the spectacle side is closed. This prevents any fluid from flowing through the flange, ensuring the integrity and safety of the pipeline system.

4. Temporary Blockage: In certain situations, it may be necessary to temporarily block the flow of fluid in a pipeline. Examples include isolating a section for maintenance, controlling the flow of different process streams, or redirecting the flow to alternative routes. The blind spectacle flange can be rotated to the closed position to effectively block off the flow.

5. Flexibility and Control: With the ability to rotate the spectacle blind, operators have the flexibility to control the flow in a pipeline system as needed. This allows for efficient maintenance, testing, and control of fluid movement.

6. Safety Considerations: The blind spectacle flange helps ensure the safety of personnel and equipment during maintenance or repair activities. By shutting off the flow through the flange, potential hazards associated with live fluids can be eliminated, allowing work to be carried out safely.

Application
Blind spectacle flanges are employed in a wide range of industries, including oil and gas, chemical, petrochemical, and power generation. They are used in various applications, such as pipelines, pressure vessels, vessels, tanks, and processing equipment.