What is Spade and Ring Spacer Flange?

A Spade and Ring Spacer Flange (also known as a spectacle blind flange when used as a pair) is a piping component used in process piping systems to provide a positive shut-off or to isolate a section of the line during maintenance or inspection. The spade (also called a single-blind) is a solid metal plate that blocks flow, while the ring spacer (or spacer) is a metal ring with the same outside diameter and bolt pattern but with an open bore, allowing flow. These components are used as a pair and can be swapped manually depending on the system’s operational needs.

They are primarily used where frequent line isolation is required without fully removing the flange connection. A handle or tab is often included for easy identification and handling.

Key Features of Spade and Ring Spacer Flange:

• Dual Functionality: The spade blocks flow, and the ring spacer allows flow – together, they provide easy manual line isolation.
• Handle for Identification: Each piece typically has a tab or handle for visual identification (solid for spade, open for spacer).
• Custom Sizes: Manufactured to match various pipe sizes and pressure ratings (ASME, ANSI, API, etc.).
• Corrosion Resistance: Available in stainless steel, carbon steel, and other alloys suitable for corrosive environments.
• No Moving Parts: Simple mechanical solution – low risk of mechanical failure compared to valves.
• Easy Installation: Typically installed between two flanges in a pipeline using standard bolting.

Common Uses of Spade and Ring Spacer Flange:

• Process Piping Systems: Ideal for petrochemical, oil & gas, and chemical industries where regular line isolation is required.
• Maintenance and Safety: Used to positively isolate a pipeline section during maintenance or repair.
• Pressure Testing: Can be used during hydrostatic or pneumatic testing by installing the spade to block off flow.
• Temporary Isolation: For equipment that may need to be periodically removed or isolated without disturbing the entire system.
• Hazardous Service Lines: Provides visual confirmation of line isolation in critical safety applications.