Spectacle Blinds (Figure 8)
for Piping Systems
Spectacle blinds — also known as spectacle blind flanges or figure 8 blinds — aren't off-the-shelf parts from USA Industries. As a custom shop, we engineer and supply precision-cut blind solutions for piping systems worldwide. Our spectacle blinds, paddle blinds, and blind flanges can be built to any thickness, handle type, alloy, or coating you need.
- Flange Rating (150#, 300#, 600#, 900#, 1500#, 2500#)
- Size (1/2" – 96")
- Face Type (Flat, Raised, RTJ Male or Female — Oval or Octagonal cut)
- Mill or Serrated Finish (125/250 RMS)
- Blind Thickness (Isolation, Hydro, Custom)
- Steel Material Type (Carbon, Stainless – 304, 316, Other)
- Quantity Needed
- Necessary Delivery Date
| Specification | Details |
|---|---|
| Sizes | 1/2" – 96" |
| Thickness Options | Isolation • Hydro • Custom |
| Rating Classes | 150# • 300# • 600# • 900# • 1500# • 2500# |
| Stocked Alloys | 516-Gr70 CS • 304/316 SS (Any Available Alloy) |
| Materials Origin | USA |
| Face Options | Flat • Raised • RTJ Male • RTJ Female |
| Gasket Types | Octagonal • Oval |
| Finish Options | Serrated (125/250 RMS) • Mill |
| Coating Options | Various |
Spectacle blinds — also referred to as spectacle blind flanges — have two metal discs connected by a handle, resembling a pair of spectacles. While one disc is solid, the other features an opening — enabling flow through the system when aligned with the pipe or vessel.
Uses for Spectacle Blinds
Blind Face, Gasket & Finish Types
USA Industries supplies spectacle blinds in all standard face configurations — Flat Face, Raised Face, RTJ Male, and RTJ Female — with mill or serrated (125/250 RMS) finish options and all standard RTJ gasket profiles, on either disc.
USA Industries NSF ANSI/CAN 61 certification applies exclusively to our stainless steel products.
NSF/ANSI 61 is the NSF standard that ensures any materials, coatings, or products that come into contact with drinking water do not leach harmful contaminants into the water at unsafe levels.
- Pipes & fittings (metal, plastic, concrete, etc.)
- Valves & gaskets
- Meters & water treatment devices
- Coatings, linings, sealants, solders
- Any materials that touch drinking water in distribution systems
- Leaching of lead, arsenic, mercury, and other heavy metals
- Leaching of organic contaminants (e.g., solvents, plasticizers)
- Other harmful chemicals that might migrate from material into water
- Required in most U.S. states and Canadian provinces for public water systems
- Certifies products are safe for use with potable (drinking) water
- Reduces liability and demonstrates regulatory compliance
Rent or buy the Patented EZ Lock Blind Rack from the industry leader in blind storage solutions.
- Safely store and organize "T" & "7" handle paddle blinds
- Easy and safe to transport storage unit with lockable shelves.
- Store up to 884 blinds
(line size and blind thickness dependent) - Rental and purchase options available
- Reduces handling damage and improves organization
- Order fully stocked and receive discount
Spectacle Blind vs. Paddle Blind & Spacer
A spectacle blind flange combines the function of a paddle blind and a spacer into a single piece — but it isn't always the right choice. Use the comparison below to decide which solution fits your application, and the quick finder to confirm configuration details.
Spectacle Blind vs. Paddle Blind + Spacer
| Feature | Spectacle Blind (Figure 8) | Paddle Blind + Spacer |
|---|---|---|
| Construction | Single machined piece — solid disc + open disc joined by a handle | Two separate components: paddle blind and a separate spacer ring |
| Installation | Stays permanently in the line — rotate to switch between isolation and flow | Paddle blind removed entirely to restore flow; spacer remains |
| Storage | No separate storage needed — the blind never leaves the line | Removed paddle blind requires safe storage (e.g., EZ Lock Blind Rack®) |
| Best For | Frequent isolation/flow switching, permanent in-line isolation points, pressure testing points used repeatedly | Standard turnaround isolation where blinds are removed for extended periods |
| Available From USA Industries | ✓ | ✓ |
Thickness Options Compared
| Thickness Type | Primary Use | Pressure Rating | Typical Applications | Available |
|---|---|---|---|---|
| Isolation Thickness | Standard flow isolation | Full rated pressure class | Routine maintenance isolation, permanent in-line isolation points | ✓ |
| Hydro Thickness | Hydrostatic pressure testing | Hydrotest pressure (1.5× MAWP) | Pre-commissioning testing, repeated pressure integrity verification points | ✓ |
| Custom Thickness | Special application requirements | Engineered to specification | High-cycle service, unusual pressure/temperature combinations | ✓ |
Frequently Asked Spectacle Blind Flange Questions
What Is a Spectacle Blind?
Spectacle blinds — also called spectacle blind flanges, figure 8 blinds, or figure 8 blind flanges — are precision-manufactured isolation devices consisting of two discs joined by a connecting web or handle, resembling a pair of eyeglasses (hence "spectacle"). One disc is solid and provides full isolation; the other has a bore that matches the pipe ID and allows full flow when rotated into position.
Unlike a paddle blind, which is removed from the line to restore flow, a spectacle blind stays permanently installed. Rotating the assembly 180° swaps which disc sits in the flow path — switching between full isolation and full flow without breaking the joint or removing any components.
Spectacle Blind vs. Paddle Blind & Spacer
This is one of the most common selection questions we get, and the answer depends on how often the isolation point needs to switch between blocked and open:
- Spectacle blinds are ideal for isolation points that are switched repeatedly — pressure test points used on a recurring schedule, or permanent isolation locations where operators need a fast, verifiable way to toggle flow without removing hardware.
- Paddle blinds and spacers remain the better choice for standard turnaround isolation, where the blind is removed entirely for an extended period and flow is fully restored using just the spacer — no spectacle blind footprint required in the open position.
For more on paddle blind selection and isolation vs. hydro thickness, see our Paddle Blinds page and Blind Thickness Chart.
Isolation vs. Hydro Thickness — What's the Difference?
As with paddle blinds, spectacle blind thickness must match the application:
- Isolation thickness is designed to handle the maximum allowable working pressure (MAWP) of the system at operating conditions — used for routine isolation
- Hydro thickness is designed for hydrotest pressure, typically 1.5× the MAWP — used at points where pressure integrity testing happens regularly
Use our Paddle Blind Thickness Chart to look up the correct thickness for your line size and pressure class, or call our technical team and we'll confirm based on your exact requirements.
Spectacle Blind Material Options
Spectacle blind material should match or be compatible with the pipe material and process fluid to prevent galvanic corrosion and ensure safe, long-term isolation.
- SA516 Grade 70 Carbon Steel — Standard stocked material; most common for general industrial and refinery applications
- 304 & 316 Stainless Steel — Corrosion-resistant; NSF ANSI/CAN 61 certified; widely stocked
- Duplex & Super Duplex Stainless Steel — High strength and corrosion resistance for demanding environments
- Monel, Inconel, Incoloy, Hastelloy — Extreme temperature and chemical resistance
- Titanium — Chemical processing and highly corrosive services
- Custom alloys available — Any available alloy; PMI verified on all raw materials
Why Choose USA Industries Spectacle Blinds?
USA Industries has been manufacturing isolation blinds since 1982 from our facilities in Texas, Louisiana, and Oklahoma. We are the manufacturer — not a distributor — which means faster lead times, custom capabilities, and direct technical support from people who know the product.
- One-piece or two-piece construction — large diameters and custom configurations available
- Custom sizes, thicknesses, and alloys — any specification, fast turnaround
- Sizes from 1/2" to 96" — ASME B16.48, B16.47 Series A & B, B16.5
- Single or dual tie-bar (web) configurations available
- True raised face (1/16"–1/8" lip), RTJ Male/Female, and all standard gasket types
- Vent holes and lifting lugs available on either disc
- Color-coded by class rating — instant visual identification in the field
- U.S.-produced steel, PMI verified on all raw materials
- Rent or purchase — EZ Lock Blind Rack® available for paddle blind storage
- ISO 9001:2015 certified manufacturing
- 24/7/365 emergency availability — Houston TX, Corpus Christi TX, Prairieville LA, Broken Arrow OK
Technical Documentation
