Spectacle blind symbol
Also called Figure 8 blind, Spec blind
A spectacle blind is a plate with a solid disc and an open ring, joined like a figure 8, fitted between two flanges. Turned one way it closes the line; turned the other it lets flow through.
What the spectacle blind symbol means
A spectacle blind is a plate with a solid disc and an open ring, joined like a figure 8, fitted between two flanges. Turned one way it closes the line; turned the other it lets flow through.
How it is drawn
A figure 8 between two flanges. The part in the line shows the position: the solid disc for closed, the ring for open.
Isometric SVGWhere you see it
Positive isolation points for maintenance, start-up and testing.
What is written next to it
On the isometric, the spectacle blind usually carries the size, rating and the position it is installed in, open or closed.
What gets checked on site
For a spectacle blind, the site checks usually cover its position against the isolation or test plan, before and after the pressure test. Each check is recorded against the line and the joint, so the line can go into its test pack and be handed over with its evidence. See the ITR guide.
Related symbols
Frequently asked questions
What does the spectacle blind symbol look like?
A figure 8 between two flanges. The part in the line shows the position: the solid disc for closed, the ring for open.
Where is a spectacle blind used?
Positive isolation points for maintenance, start-up and testing.
- In production since 2014
- Thousands of daily users
- On MODEC FPSO projects since 2016