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Spectacle Blind Flanges
For reliable isolation and inspection capabilities in critical pipeline systems, Spectacle Blind Flanges from Fortis Forge are valued for their durable construction, easy operability, and superior sealing performance. These specialty flanges are engineered to meet stringent industry standards such as ASME B16.48, ASTM A105, and applicable DIN specifications, offering a practical solution for systems requiring frequent maintenance or flow diversion.
Manufactured using carbon steel or mild steel, our spectacle blind flanges are fabricated from a single metal plate and consist of two discs—one solid (blind) and one open (spacer)—connected by a small web or tie-bar. This design allows quick switching between open and closed states by simply rotating the flange without disassembling the pipeline. They are ideal for isolating piping sections during maintenance or shutdown operations in high-pressure environments.
With advanced cutting, precision machining, and dimensional accuracy, Fortis Forge Spectacle Blind Flanges ensure tight sealing, structural integrity, and long-term reliability in extreme operating conditions. Commonly used in oil & gas, petrochemical plants, offshore platforms, power generation, and refineries, they serve as a robust safety mechanism to block flow and protect downstream equipment.
Available in a wide range of sizes, pressure ratings (Class 150 to Class 1500), and face types (RF, FF), our Spectacle Blinds are customized for operational efficiency and code compliance. Whether used as a permanent block valve substitute or temporary inspection tool, Fortis Forge Spectacle Blind Flanges offer a secure, maintenance-friendly, and cost-effective solution to support piping safety and system control.
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- Size
½” to 48” (DN15–DN1200)
- Standard
ASME B16.48 / ASME B16.5 / EN 1092-1
- Material
Carbon Steel (ASTM A105) / Mild Steel (IS 2062)
- Enquiry
What is a Spectacle Blind Flange?
A Spectacle Blind Flange is a safety device used in piping systems to either allow flow or completely block it. It consists of two metal discs—one solid (blind) and one open (spacer)—connected by a web or tie bar. By rotating the flange assembly, operators can switch between open and closed states, ensuring safe maintenance or system isolation without removing piping sections.
Open Position (Spacer): Allows fluid/gas flow through the pipeline.
Closed Position (Blind): Blocks the flow entirely, ensuring safe inspection, maintenance, or system shutdown.
Spectacle blinds are especially useful where frequent isolation is required without dismantling pipe sections.
Material Grades We Use
At Fortis Forge, our Spectacle Blind Flanges are manufactured from high-grade materials to ensure mechanical strength, corrosion resistance, and long service life.
Carbon Steel (ASTM A105)
→ Excellent strength and durability. Ideal for high-pressure, high-temperature applications.Mild Steel (IS 2062)
→ Known for flexibility and cost-effectiveness in general industrial environments.Stainless Steel (304 / 316)
→ Superior corrosion resistance. Perfect for chemical, offshore, and marine use.
Each flange is precision-machined to maintain tight tolerances and meet or exceed international standards.
Manufacturing Standards at Fortis Forge
Our Spectacle Blind Flanges are produced with utmost attention to detail, following rigorous procedures:
Hot forging & CNC machining
Heat treatment for strength enhancement
Non-destructive testing (NDT) for internal flaws
Hydrostatic pressure testing for leak and pressure integrity
Full certification & traceability to international norms
Applications Across Industries
Fortis Forge Spectacle Blind Flanges are trusted for secure flow isolation in critical sectors:
Oil & Gas Refineries
Offshore Platforms & Pipelines
Power Plants (Thermal, Nuclear)
Chemical & Petrochemical Facilities
Marine & Shipbuilding
Industrial Processing Units
Their dual-function design and rugged performance make them essential for safety compliance and operational reliability.
Why Choose Fortis Forge?
High-quality raw materials with MTCs
In-house quality assurance & testing
Precise forging, cutting, and machining
On-time global delivery with documentation
Expert technical support and customization options
Spectacle Blind Flanges – Class 150/300/600, Carbon Steel Spectacle Blind Flange Fittings, Mild Steel Spectacle Flanges, ASTM A105 Spectacle Blind Flanges, ASME B16.48 Flanges, High Pressure CS/MS Spectacle Blinds, Spade & Spacer Flanges, Raised Face & Flat Face Spectacle Flange Manufacturer in India
As a leading manufacturer of Spectacle Blind Flanges, Fortis Forge is committed to delivering precision-engineered piping components that meet stringent global standards. Our spectacle blinds are manufactured with a focus on dimensional accuracy, machining excellence, and long-term sealing reliability. Built to comply with ASME B16.48, ASTM A105, and equivalent DIN standards, our products are designed to provide a reliable and maintenance-friendly solution for pipeline isolation and flow regulation.
Spectacle Blind Flanges, also known as figure-8 blinds, are essential components for pipeline inspection, maintenance, and shutdown operations. They consist of two metal discs—one solid (blind) and one open (spacer)—connected by a web or tie bar, allowing the user to rotate between open and closed positions. These flanges are widely used in critical applications where absolute shutoff and safe isolation of pipeline sections are necessary.
Manufactured using high-grade carbon steel or mild steel (ASTM A105, IS 2062), our spectacle blinds are ideal for high-pressure and high-temperature environments, such as oil & gas, refineries, chemical processing plants, power stations, and offshore facilities. They are available in a range of sizes, pressure classes (150#, 300#, 600#, etc.), and face types (RF, FF) to suit diverse operational requirements.
Whether for permanent installation or temporary isolation, Fortis Forge’s Spectacle Blind Flanges provide unmatched safety, corrosion resistance, and long-term reliability—helping engineers maintain efficient and secure fluid control across critical piping systems.
Spectacle Blind Flanges, Carbon Steel Spectacle Blind Flange Fittings, Mild Steel Spectacle Blinds, ASME B16.48 Spectacle Flanges, Class 150 & Class 300 Spectacle Blind Flanges, Spectacle Blind Flange Manufacturers in India
- Spectacle Blind Flanges Specification
| Specifications | ASME B16.48 / BS 4504 / EN 1092-1 |
| Size Range | ½” to 48” (DN15 to DN1200) |
| Types | Spectacle Blind Flange, Spacer & Spade, Paddle Blank, Line Blind |
| Pressure Class | Class 150, 300, 600, 900, 1500 |
| Material Grades | Carbon Steel (ASTM A105), Mild Steel (IS 2062), Stainless Steel (304/316) |
| Standard | ASTM, ASME, ANSI, DIN, EN, JIS, BS |
| Applications | Oil & Gas, Refineries, Offshore Platforms, Chemical Processing, Power Plants, Marine Pipelines |
- Spectacle Blind Flanges Dimensions
Class 150 SPECTACLE BLINDS
| NPS | Outside Ø A | Inside Ø B | Centerline C | Thickness t | Web Width W |
|---|---|---|---|---|---|
| 1/2 | 45 | 16 | 60 | 3 | 38 |
| 3/4 | 54 | 21 | 70 | 3 | 38 |
| 1 | 64 | 27 | 80 | 3 | 38 |
| 1¼ | 73 | 42 | 90 | 6.4 | 38 |
| 1½ | 83 | 48 | 100 | 6.4 | 38 |
| 2 | 102 | 61 | 120 | 6.4 | 51 |
| 2½ | 107 | 73 | 140 | 6.4 | 51 |
| 3 | 133 | 89 | 150 | 6.4 | 64 |
| 3½ | 159 | 102 | 175 | 9.7 | 64 |
| 4 | 172 | 114 | 190 | 9.7 | 64 |
| 5 | 194 | 141 | 215 | 9.7 | 76 |
| 6 | 219 | 168 | 240 | 12.7 | 76 |
| 8 | 276 | 219 | 300 | 12.7 | 76 |
| 10 | 337 | 273 | 360 | 15.7 | 102 |
| 12 | 406 | 324 | 430 | 19.1 | 102 |
| 14 | 448 | 356 | 475 | 19.1 | 108 |
| 16 | 511 | 406 | 460 | 22.4 | 108 |
| 18 | 546 | 457 | 580 | 25.4 | 114 |
| 20 | 603 | 508 | 635 | 28.4 | 121 |
| 24 | 714 | 610 | 750 | 31.8 | 140 |
Class 300 SPECTACLE BLINDS
| NPS | Outside Ø A | Inside Ø B | Centerline C | Thickness t | Web Width W |
|---|---|---|---|---|---|
| 1/2 | 51 | 16 | 65 | 6.4 | 38 |
| 3/4 | 64 | 21 | 80 | 6.4 | 38 |
| 1 | 70 | 27 | 90 | 6.4 | 38 |
| 1¼ | 79 | 42 | 100 | 6.4 | 38 |
| 1½ | 92 | 48 | 115 | 6.4 | 38 |
| 2 | 108 | 61 | 125 | 9.7 | 51 |
| 2½ | 127 | 73 | 150 | 9.7 | 51 |
| 3 | 146 | 89 | 170 | 9.7 | 64 |
| 3½ | 162 | 102 | 185 | 12.7 | 64 |
| 4 | 178 | 114 | 200 | 12.7 | 64 |
| 5 | 213 | 141 | 235 | 15.7 | 76 |
| 6 | 248 | 168 | 270 | 15.7 | 76 |
| 8 | 305 | 219 | 330 | 22.4 | 76 |
| 10 | 359 | 273 | 385 | 25.4 | 102 |
| 12 | 419 | 324 | 450 | 28.4 | 102 |
| 14 | 483 | 356 | 515 | 31.8 | 108 |
| 16 | 536 | 406 | 570 | 38.1 | 108 |
| 18 | 594 | 457 | 630 | 41.1 | 114 |
| 20 | 651 | 508 | 685 | 44.5 | 121 |
| 24 | 772 | 610 | 810 | 50.8 | 140 |
Class 600 SPECTACLE BLINDS
| NPS | Outside Ø A | Inside Ø B | Centerline C | Thickness t | Web Width W |
|---|---|---|---|---|---|
| 1/2 | 51 | 16 | 65 | 6.4 | 38 |
| 3/4 | 64 | 21 | 80 | 6.4 | 38 |
| 1 | 70 | 27 | 90 | 6.4 | 57 |
| 1¼ | 79 | 37 | 100 | 9.7 | 57 |
| 1½ | 92 | 43 | 115 | 9.7 | 67 |
| 2 | 108 | 55 | 125 | 9.7 | 57 |
| 2½ | 127 | 67 | 150 | 12.7 | 67 |
| 3 | 146 | 83 | 170 | 12.7 | 67 |
| 3½ | 159 | 96 | 185 | 15.7 | 76 |
| 4 | 191 | 108 | 215 | 15.7 | 76 |
| 5 | 238 | 135 | 265 | 19.1 | 86 |
| 6 | 264 | 162 | 290 | 22.4 | 86 |
| 8 | 318 | 212 | 350 | 28.4 | 95 |
| 10 | 397 | 265 | 430 | 35.1 | 105 |
| 12 | 454 | 315 | 490 | 41.1 | 105 |
| 14 | 489 | 346 | 525 | 44.5 | 114 |
| 16 | 562 | 397 | 605 | 50.8 | 124 |
| 18 | 610 | 448 | 655 | 53.8 | 133 |
| 20 | 679 | 497 | 725 | 63.5 | 133 |
| 24 | 787 | 597 | 840 | 73.2 | 152 |
The Spectacle Blind Flange price can vary depending on the size, pressure rating (150#, 300#, etc.), material grade (carbon steel, mild steel, stainless steel), and specific design such as paddle blank, spacer, or full spectacle. Typically, the price for carbon steel or mild steel spectacle blind flanges ranges from ₹250 to ₹2,500 per piece, depending on dimensions, thickness, and compliance with standards like ASME B16.48 or EN 1092-1. As a trusted spectacle blind flange manufacturer and supplier in India, Fortis Forge offers highly competitive pricing while ensuring precision machining, strict dimensional tolerances, and robust product integrity suited for critical isolation applications in pipelines and process systems.
Quality Assurance
To preserve the high standards of our selection of Forged Fittings, Buttweld Fittings, Flanges and we have always adhered to a systematic quality management process.
Team of Experts
Our staff of experts is vibrant and talented, and they have always been our largest supporters and contributors to our success.
- Equivalent Grades of Spectacle Blind Flanges
| STANDARD | WERKSTOFF NR. | UNS | JIS | BS | GOST | AFNOR | EN |
| ASTM A516 Gr.70 / A105 | 1.0345 / 1.0432 | K02700 / K03504 | SB 410 / SF 440A | 1501-161-430A | 20 / 09G2S | NF A36-205 | P265GH / P250GH |
If you would like to inquire or place an order.
+91 83330 05894
Forged Fittings, Buttweld Fittings and Flanges Manufacturer in India
- Manufactured from high-strength carbon steel grades
- Available in forged, buttweld, and flange configurations
- Precision-machined for leak-proof, high-pressure applications
- Heat-treated and normalized to ensure durability and strength
- Tested for dimensional accuracy and pressure resistance
- Corrosion-resistant coatings available on request
- Application Industries
