SPFL® INDUSTRIAL FLANGE RANGE
Spectacle Flange
Spectacle blind, also called a figure-eight line blank, combines a solid blank and an open spacer for a planned line-isolation arrangement.
Request a Quote Technical RFQ Checklist
Stainless Steel & High-Nickel Alloy Spectacle Flange Grades
Specify SS 304, SS 316, SS 310, SS 904L, HASTELLOY, Alloy 20, MONEL or INCONEL in your spectacle flange enquiry. Include the exact grade or UNS designation, flange size, pressure class, facing, quantity and required material test certificate.
| Material category | Grade / alloy | Technical designation to confirm |
|---|---|---|
| Stainless steel | SS 304 / 304L | For forged flange enquiries: ASTM A182 F304 / F304L where required by the project. State the exact grade, not just SS. |
| Stainless steel | SS 316 / 316L | For forged flange enquiries: ASTM A182 F316 / F316L where required. 316 and 316L are separate designations. |
| Heat-resistant stainless steel | SS 310 / 310S | Specify 310 or 310S separately. Confirm the applicable product specification, heat treatment and design temperature; no automatic substitution. |
| High-alloy austenitic stainless steel | SS 904L | 904L is stainless steel with high nickel and molybdenum content, not an INCONEL or MONEL grade. Specify the applicable product standard and certificate requirement. |
| Nickel-alloy family | HASTELLOY® | State the exact alloy: e.g. C-276 (UNS N10276) or C-22 (UNS N06022). Family name alone is insufficient; examples are not a stock declaration. |
| High-nickel austenitic alloy | Alloy 20 (UNS N08020) | Specify Alloy 20 and the applicable product form/specification. Do not treat it as equivalent to 904L or 316L. |
| Nickel-copper alloy family | MONEL® | State the exact alloy, e.g. MONEL 400 (UNS N04400), with product specification. Other MONEL grades must be identified separately. |
| Nickel-alloy family | INCONEL® | State the exact alloy, e.g. INCONEL 600 (UNS N06600) or INCONEL 625 (UNS N06625). These are different grades, not interchangeable. |
Supply availability, manufacturing route, applicable material specification and suitability for the selected flange configuration are confirmed during technical review. This table is not a claim that every grade is stocked in every flange type. Dimensional standards such as ASME B16.5 do not by themselves define material grade or approve service conditions.
Request a Grade-Specific Quote
Material naming references
904L stainless steel · HASTELLOY alloy designations · Alloy 20 · MONEL alloy designations · INCONEL alloy designations. External references establish naming only, not Shri Parvati inventory, affiliation or certification.
Quick Specifications
Use this specification checklist for your enquiry. It is not a declaration of stocked grades, available sizes or certified service suitability.
| Parameter | Required specification |
|---|---|
| Product / designation | Spectacle Flange / Spectacle Blind / Figure-8 Line Blank |
| Dimensional reference | ASME B16.48; state the required edition and approved drawing. This is a technical reference, not a blanket compliance claim. |
| Material / grade | Specify the plate or other approved material standard and grade; do not infer a forged-flange grade from the mating flange. |
| Size / bore | Specify NPS or DN plus actual bore, pipe outside diameter and wall or schedule where relevant. Confirm quoted dimensions before ordering. |
| Pressure class / rating | As specified by the design and mating flange; confirm the applicable dimensional and pressure-temperature requirements. |
| Facing / gasket | Specify RF, FF, RTJ or other engineered facing only as applicable to the selected configuration. |
| Critical dimensions | Line-blank thickness, spacer opening, centre spacing, mating flange class and gasket arrangement |
| Inspection / documents | State required material certificate, dimensional inspection, marking and any project-specific testing. Document availability is confirmed with the quotation. |
| Quantity / supply scope | Specify pieces or sets, mating components, delivery destination and requested lead time. |
Technical Selection Notes
Line-blank thickness, spacer opening, centre spacing, mating flange class and gasket arrangement are important to spectacle flange selection. A nominal size and material name alone do not establish mating compatibility. Compare the complete connection details with the approved piping or equipment drawing.
Specify the plate or other approved material standard and grade; do not infer a forged-flange grade from the mating flange. When enquiring about a stainless-steel grade, use its complete product-standard designation rather than only a commercial label such as “SS 316”. Any grade substitution needs project approval.
Application Areas
Planned isolation points in process plants, oil and gas facilities and maintenance systems. These are application contexts, not an approval for every pressure, temperature, fluid or installation.
For pharma, dairy or food-related projects, distinguish utility piping from product-contact hygienic connections. Specify surface finish, cleaning requirements and applicable hygienic design; an ordinary industrial flange is not automatically a sanitary fitting.
Request a Technical Quotation
Send the spectacle flange requirement, quantity, material specification, nominal size, class or design rating, facing, service conditions, line-blank thickness, spacer opening, centre spacing, mating flange class and gasket arrangement, and delivery location. Supply scope and lead time are confirmed in the quotation.
For a spectacle flange supplier enquiry, attach your purchase specification or drawing. Ask for the exact manufacturer identity, material traceability and inspection scope required by your project. We will review the requested configuration before confirming supply.
Send Spectacle Flange Requirement
Need a technical PDF? Request the approved drawing or dimensional sheet with your enquiry; no unverified download is offered here.
Frequently Asked Questions
Is Spectacle Flange technically a conventional pipe flange?
The more precise name is spectacle blind or figure-eight line blank. It is installed between mating flanges; its dimensional reference is different from that of an ordinary bolted pipe flange.
What should I send to request a quotation?
Send the spectacle flange requirement, quantity, material specification, nominal size, class or design rating, facing, service conditions, line-blank thickness, spacer opening, centre spacing, mating flange class and gasket arrangement, and delivery location. Supply scope and lead time are confirmed in the quotation.
Related Product Categories
Flanges · Pipe Fittings · Bolts · Grades & Standards
Related categories are enquiry suggestions; gasket, fastener and mating-part compatibility must be checked against the complete joint design.