SS Blind Flange Supplier India | ASTM A182 F304 F316 F316L | Class 150 to 900 | DN15–DN900 | RF FF RTJ | ASME B16.5 B16.47 | KELOR

Description

SS Blind Flange Supplier India | ASTM A182 F304 / F316 / F316L | Class 150–900 | DN15–DN900 | Raised Face / Flat Face / RTJ | ASME B16.5 / B16.47 | KELOR

Supplier: Krishna Industries (KELOR) – Ahmedabad, Gujarat, India
Established: 2017 | GSTIN: 24AKLPP6499B1ZT | IEC: AKLPP6499B
MOQ: 10 Nos | Material: ASTM A182 F304 / F316 / F316L / F304L
Standard: ASME B16.5 / B16.47 | Sizes: DN15–DN900 | Pressure: Class 150–900

SS Blind Flange Supplier in India

Krishna Industries (KELOR), based in Ahmedabad, Gujarat, is a B2B supplier of Stainless Steel Blind Flanges — ASTM A182 F304 (SS304) / F316 (SS316) / F316L (SS316L) / F304L forged — solid plate with no central bore — raised face (RF) standard / flat face (FF) / ring type joint (RTJ) — Class 150 / 300 / 600 / 900 — DN15 (½”) to DN900 (36″) — ASME B16.5 (DN15–DN600) / ASME B16.47 Series A/B (DN650–DN900) — ASME B16.5 thickness per class and size — MTC ASTM A182 heat certificate — GST invoice — MOQ 10 Nos — Pan India dispatch from Ahmedabad.

A blind flange is a solid flanged plate — no bore — that bolts to the face of any standard flanged connection to permanently or temporarily close the pipeline end. Unlike weld neck or slip-on flanges that connect two pipe sections, a blind flange terminates a pipe run, blanks a vessel nozzle, or closes a pipeline section for pressure testing. The solid plate must withstand the full line pressure across its unsupported area — ASME B16.5 specifies minimum plate thickness per pressure class and nominal pipe size, which is why blind flanges are thicker and heavier than the equivalent weld neck or slip-on flange of the same class.

Three Primary Applications — When to Specify SS Blind Flange

Blind Flange vs Spectacle Blind — Which to Specify

Grade and Facing Selection

The same grade and facing selection rules that apply to SS weld neck and slip-on flanges apply to SS blind flanges — the blind flange must always match the mating flange in both material grade and facing type.

For full explanation of SS grade selection (F304 vs F316 vs F316L sensitisation) and facing selection, see SS Weld Neck Flange page.

Technical Specifications

Applications in Indian Industries

• EPC project piping — pressure test boundaries — F316L RF Class 150/300 DN25–DN600 — hydrostatic pressure testing of SS piping spools before insulation and commissioning — blind flanges installed at test section boundaries — reused across multiple test sections — supplied in sets with the project piping BOM — F316L matches the piping grade throughout — MTC required for EPC project QC records
• Pharmaceutical plants — spare nozzle blanking — F316L RF Class 150 DN25–DN150 — blanking spare nozzles on SS process vessels, reactors, and storage tanks — future tie-in provision for plant expansion — GMP documentation requirement: blind flange grade and MTC must match vessel nozzle specification — Class 150 adequate for most pharma utility vessel pressures
• Chemical plant — vessel and header nozzle closure — F316 or F316L RF or RTJ Class 150–600 DN50–DN600 — spare nozzle blanking on SS reactors, heat exchangers, distillation columns — future branch tie-in provisions on SS process headers — Class 600 RTJ for high pressure chemical reactor nozzle closures — MTC and dimensional inspection for chemical plant vessel inspection records
• Oil and gas — pipeline end closure and test boundaries — F316 RTJ Class 600/900 DN50–DN300 — end closure on SS utility and chemical injection piping — hydrostatic test boundaries during commissioning — RTJ facing for Class 600+ joints in oil and gas service — supplied with matching SS316 RTJ oval rings
• Food and beverage — utility piping end closure — F304 or F316L RF Class 150 Sch 10S/40S DN25–DN150 — end closure on utility piping (cooling water, steam, CIP) during construction and phased plant commissioning — F316L for food GMP documentation compliance — Class 150 adequate for food plant utility pressures — future tie-in provisions for planned plant expansion connections

Related Products — Krishna Industries (KELOR)

• SS Weld Neck Flange — ASTM A182 F304/F316/F316L — Class 150–1500 — inline connection flange for high pressure SS piping — pairs with blind flange at pipeline ends in the same SS piping system
• SS Slip-On Flange — Class 150/300/600 — lower cost inline connection for utility SS piping — pairs with blind flange at end closures and test boundaries in the same system
• Threaded and Other Flange Types — CS slip-on, weld neck, threaded, socket weld flanges — for CS piping systems where SS blind flanges pair with CS inline flanges at test boundaries
• Stud Bolts — ASTM A193 B8M (SS316) — SS316 stud bolts for SS blind flange bolting in corrosive service — B8M studs prevent galvanic corrosion at SS flange joints
• Gate Valve — upstream isolation valve before blind flange at pipeline end closure — standard practice to install gate valve before permanent blind flange for future depressurisation access

Frequently Asked Questions

1. Why is a blind flange thicker than a weld neck or slip-on flange of the same pressure class and size?

A weld neck or slip-on flange has a central bore — the pipe passing through the bore provides structural support and the pressure load is carried by the pipe wall, not by the flange plate itself. A blind flange has no bore — the solid plate must resist the full line pressure acting across its entire unsupported area. As pipe size increases, the unsupported area increases rapidly and the plate must be thicker to resist bending. ASME B16.5 specifies the minimum thickness for blind flanges per pressure class and nominal pipe size — a DN300 Class 300 blind flange is substantially thicker and heavier than a DN300 Class 300 weld neck flange. Always order blind flanges to ASME B16.5 minimum thickness rather than specifying the same thickness as the mating inline flange.

2. Can a blind flange be used as a pressure test boundary for test pressures above Class 150 rating?

ASME B31.3 requires hydrostatic test pressure of 1.5 times the design pressure. If the design pressure of the piping system is close to the maximum allowable pressure for Class 150 — approximately 20 bar at ambient for SS F316 — the test pressure of 1.5× design may exceed the Class 150 blind flange rating. In this case, specify Class 300 blind flanges for the test boundary even if the system piping uses Class 150 flanges. Class 300 SS F316 blind flange is rated approximately 52 bar at ambient — providing adequate margin for the hydrostatic test. After testing, Class 300 blind flanges can be retained as the permanent end closure (Class 300 at Class 150 service is perfectly acceptable) or replaced with Class 150 blind flanges for the permanent installation.

3. Should a vent or drain tapping be added to the blind flange?

For permanent end closures on piping systems that may need to be vented or drained during maintenance, specify a tapped vent connection (typically DN15 BSP threaded) on the blind flange face — this allows the pipeline to be vented or drained without removing the blind flange. For pressure test blind flanges, a vent tapping (DN15 BSP with plugged nipple) allows air to be purged from the top of the test section before pressurising — trapped air in a hydrostatic test creates a compressible cushion that stores energy and can cause a sudden pressure release on seal failure. For most permanent nozzle blanking applications, an untapped blind flange is standard. Specify tapped blind flanges at order stage with required tapping size and thread type.

4. What gasket should I use with SS blind flanges?

For Class 150 raised face: compressed asbestos-free fibre (CAF) or rubber sheet gasket — economical for water, HVAC, and utility service. For Class 150–300 raised face in chemical or pharma service: PTFE envelope gasket or spiral wound SS316/PTFE gasket. For Class 300 and above raised face in process service: spiral wound SS316/graphite gasket — this is the standard Indian refinery and chemical plant gasket for Class 300+ SS flanged joints. For RTJ Class 600+: SS316 oval ring gasket — ring is replaced every time the joint is opened. Always match gasket material to the process fluid chemical compatibility — a gasket failure on a blind flange closure can result in sudden full bore release of line contents.

5. What is the MOQ?

MOQ is 10 Nos per line item. Full project BOM supply — multiple sizes, grades, and pressure classes in one consolidated order. Documents: MTC (ASTM A182 heat certificate), dimensional inspection confirming ASME B16.5 thickness and bolt circle, GST invoice with HSN 73072100. TPI on request. WhatsApp grade, pressure class, size list, facing, and quantity for project pricing within 2 hours.

Conclusion

Krishna Industries (KELOR) supplies SS Blind Flanges for pipeline end closure, hydrostatic pressure testing, spare nozzle blanking, and future tie-in provisions — ASTM A182 F304 / F316 / F316L / F304L forged — raised face (RF) standard / flat face (FF) / ring type joint (RTJ) — Class 150 / 300 / 600 / 900 — DN15 (½”) to DN900 (36″) — ASME B16.5 / B16.47 — ASME B16.5 minimum thickness per class and size — MTC ASTM A182 heat certificate — GST invoice — Pan India dispatch from Ahmedabad. WhatsApp grade, pressure class, size list, facing, and quantity for project pricing within 2 hours.