The Figure 8 Blank, or Spectacle Blind, is a safety-critical piping component used to provide positive isolation. Named for its hourglass shape, it consists of one solid disc and one open ring connected by a web. By rotating the piece, operators can easily switch between "open" (flow) and "blind" (isolation) positions. Forged from carbon or stainless steel, these are essential for maintenance and equipment shutdowns, providing a clear visual indicator of the line's status in industrial plants.
Technical attributes
Standard: ASME B16.48
Common Name: Spectacle Blind / Figure 8
Material Grade: ASTM A105 / A182 F316L
Pressure Class: 150 to 2500 LBS
Size Range: NPS 1/2 to NPS 24
Manufacturing: Forged or Machined Plate
Facing Type: Raised Face (RF) / Female / Male
Surface Finish: 125-250 AARH (Stock Finish)
Disc Thickness: Per ASME B16.48 calculation
Web Width: Standardized per size/class
Carbon Content: Max 0.35 percent (A105)
Yield Strength: Min 250 MPa (Carbon Steel)
Tensile Strength: Min 485 MPa (Carbon Steel)
Function: Permanent system isolation
Installation: Between two standard flanges
Visual Indicator: Open/Closed status visible
Heat Treatment: Normalized (if required)
Certification: EN 10204 3.1
Service Application: Maintenance / Positive Shut-off
Contact: Jorge Yang
Phone: +86-13588258503
E-mail: sales@fluvalve.com
Whatsapp:+86-13588258503
Add: Room 331, South Building,Building 1, No.3 Jinpeng Street, Sandun Town, Xihu District, Hangzhou City, Zhejiang Province
