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IS / ANSI B16.5 · Pipe Termination
Blind Flanges
M.S. Blind Pipe Flanges Manufacturer & Supplier – Mumbai, India · Since 1999
IS / ANSI B16.5 CertifiedPrecision Machined FaceDirect ManufacturerPAN India SupplyGSTIN: 27AMZPK5174G1ZE
M.S. Blind Flanges (also called Blanking Flanges or Blank Flanges) are solid disc flanges with no central bore — used to permanently or temporarily seal and terminate the open end of a pipe, pressure vessel nozzle or valve. Manufactured from IS:2062 grade mild steel at our Darukhana, Mumbai factory, our Blind Flanges feature precision-machined face finish for leak-proof sealing. Available in sizes 15mm NB to 600mm NB in Flat Face (FF), Raised Face (RF) and Ring Joint (RJ) configurations to IS and ANSI B16.5 standards. Also used for pressure testing piping systems.
Quick Specifications
StandardIS / ANSI B16.5
Size Range15mm NB – 600mm NB
Pressure ClassClass 150, 300, 600, 900, 1500, 2500
Face TypesFlat Face (FF) / Raised Face (RF) / Ring Joint (RJ)
Material GradeIS:2062 Mild Steel (MS)
Face Finish3.2 Ra – 6.3 Ra (Machined)
Lead Time3–7 Days (Standard) | 7–15 Days (Bulk)
SupplyPAN India | Darukhana, Mumbai
25+Years Mfg.
600mmMax NB Size
Class 2500Max Rating
What Are Blind Flanges?
Blind Flanges (BL Flanges / Blanking Flanges) are solid discs manufactured from mild steel with bolt holes on the outer diameter but no central bore. They are bolted to the end of a pipe, nozzle, valve or pressure vessel opening to completely seal and close off the connection.
Primary uses of Blind Flanges: (1) Permanent pipe termination — sealing the dead end of a piping system; (2) Future expansion point — a blind flange can be removed later when the pipeline needs to be extended; (3) Pressure testing — temporarily isolating a pipe section during hydrostatic or pneumatic pressure testing; (4) Inspection access — in larger sizes (150mm NB+) blind flanges with a hand-hole or nozzle fitting are used as inspection covers.
Blind Flange vs End Cap — What's the Difference?
Both seal a pipe end, but a Blind Flange bolts onto an existing flanged pipe end using bolts — it is removable and reusable. An End Cap (Pipe Cap) is a butt-welded fitting — permanently welded onto the pipe end. Blind Flanges are preferred where future access or inspection of the pipe end is anticipated.
Why Choose I.S. Engineering Co.?
25+ Years Experience
Manufacturing Blind Flanges in Mumbai since 1999. Trusted by 500+ clients across India.
Factory-Direct Pricing
No middlemen. Buy direct from the manufacturer at the most competitive prices in Mumbai.
100% Quality Inspected
Every Blind Flanges undergoes dimensional and material inspection before dispatch from our Mumbai factory.
PAN India Delivery
Supplying to Mumbai, Pune, Delhi, Bangalore, Chennai, Hyderabad, Ahmedabad and all major cities across India.
Blind Flanges – Dimensional Specifications
| NB Size | OD (mm) | Thickness (mm) | No. Bolts | Bolt Circle (mm) | Bolt Size |
|---|---|---|---|---|---|
| 15mm | 95 | 12 | 4 | 65 | M12 |
| 20mm | 105 | 14 | 4 | 75 | M12 |
| 25mm | 115 | 14 | 4 | 85 | M12 |
| 40mm | 150 | 16 | 4 | 110 | M16 |
| 50mm | 165 | 16 | 4 | 125 | M16 |
| 80mm | 200 | 18 | 8 | 160 | M16 |
| 100mm | 220 | 18 | 8 | 180 | M16 |
| 150mm | 285 | 20 | 8 | 240 | M20 |
| 200mm | 340 | 22 | 8 | 295 | M20 |
| 250mm | 395 | 24 | 12 | 350 | M20 |
| 300mm | 445 | 24 | 12 | 400 | M20 |
| 400mm | 565 | 26 | 16 | 515 | M24 |
* Dimensions are indicative. Custom sizes available on request. Contact I.S. Engineering Co. at +91 83558 15350 for specific sizes, tolerances and full specification sheets.
Blind Flanges – Industries & Applications
Pipe End Termination
Sealing the dead end of distribution mains, process pipelines and utility piping permanently. Blind flanges allow future extension by simply unbolting.
Pressure Testing
Temporarily isolating a pipe section during hydrostatic or pneumatic pressure testing. After testing, the blind flange is unbolted and removed.
Process Isolation
Isolating process equipment (reactors, vessels, heat exchangers) from the piping system during maintenance, inspection or repair without disturbing adjacent piping.
Oil & Gas
Used in oil & gas pipelines, wellhead assemblies and gas distribution systems for line isolation. Available in higher pressure classes (Class 600, 900, 1500) for high-pressure service.
Water Treatment Plants
Used in water treatment and pumping station pipelines for temporary and permanent isolation of pipework sections during commissioning and maintenance.
Chemical Plants
Isolating chemical process lines during shutdowns or equipment changes. Material compatibility with process fluid must be verified — IS:2062 mild steel suitable for non-corrosive chemical service.
Blind Flanges – Frequently Asked Questions
What is a Blind Flange?
+A Blind Flange (also called a Blanking Flange or BL Flange) is a solid disc flange with bolt holes on the outer rim but no central bore. It is bolted to the end of a flanged pipe to completely seal and close the pipe opening. Used for pipe termination, pressure testing and future expansion points.
What is the difference between a Blind Flange and an End Cap?
+A Blind Flange is a bolted fitting — it bolts onto an existing flanged pipe end and is easily removable. An End Cap (Pipe Cap) is a butt-welded fitting permanently welded onto the pipe end. Blind flanges are preferred when future access, extension or inspection of the pipe end is anticipated.
What sizes of Blind Flanges are available?
+I.S. Engineering Co. manufactures M.S. Blind Flanges in sizes from 15mm NB to 600mm NB. All standard sizes as per IS:1538, ANSI B16.5 and BS 4504 are available. Custom sizes outside the standard range are manufactured on request.
What pressure classes are available in Blind Flanges?
+Blind Flanges are available in pressure classes: PN6, PN10, PN16 (IS:1538 standard) and Class 150, 300, 600, 900, 1500, 2500 (ANSI B16.5 standard). Higher class flanges have greater thickness and are suitable for higher operating pressures.
Can Blind Flanges be used for pressure testing?
+Yes. Blind Flanges are widely used for hydrostatic and pneumatic pressure testing of piping systems. They temporarily close the pipe end during testing and are removed afterwards. Ensure the blind flange pressure class exceeds your test pressure with adequate safety margin.
What material are your Blind Flanges made from?
+Our Blind Flanges are manufactured from IS:2062 Grade E250 Mild Steel — tensile strength 410–530 N/mm², yield strength ≥ 250 N/mm². Material conforms to Indian Standard IS:2062 and is verified before production. Material Test Certificates (MTC) available on request.
Are Blind Flanges and Blank Flanges the same?
+Yes. Blind Flanges, Blanking Flanges and Blank Flanges are all names for the same product — a solid disc flange with bolt holes but no central bore, used to seal a pipe end. They may also be called BL Flanges (from the abbreviation BL used on piping drawings). I.S. Engineering Co. manufactures all types in Mumbai from 15mm NB to 600mm NB.
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