Beyond Standard Connections: Understanding Spectacle Blinds, Spacers, and Orifice Flanges
1. The Role of Isolation and Measurement Standard flanges provide connectivity, but special operations require dedicated components for flow measurement and absolute isolation.
- Spectacle Blinds: A dual-part component (one solid plate, one open ring) resembling spectacles. It provides a positive mechanical shut-off that is visible to operators, ensuring safety during downstream maintenance.
- Orifice Flanges: Used in conjunction with orifice plates to measure the flow rate of liquids or gases. They feature “tapped” holes in the flange ring for pressure instrument connections.
- Anchor Flanges: Large, heavy forged components welded into a pipeline to restrain axial movement caused by internal pressure or temperature changes.

2. Standard References
- ASME B16.48: Governs Line Blanks (Spectacle Blinds).
- ASME B16.36: Governs Orifice Flanges.





