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Flange Identification Tool

Ordering a mating flange for an existing joint means matching the standard exactly — a Table E flange will not bolt to an ASA 150 flange. Pick the standard and size below to get the outside diameter, bolt circle, hole count and bolt size, then check them against the flange in front of you.

Flange face with the bolt circle diameter marked across opposite holes and the flange outside diameter dimensioned
Measure the flange OD, the bolt circle (PCD) and count the holes — those three numbers identify almost any flange

Still not sure?

Send a photo of the flange on WhatsApp with the outside diameter, bolt circle and hole count written on it. We identify these several times a week and will tell you exactly what to order.

💬 Send a photo

What to measure

  1. Flange outside diameter — the overall diameter of the disc, edge to edge.
  2. Bolt circle diameter (PCD) — the distance from the centre of one hole to the centre of the hole directly opposite. On flanges with an odd arrangement, measure from the centre of one hole to the far edge of the opposite hole and subtract half the hole diameter.
  3. Number of bolt holes — count them; 4, 8, 12 and 16 are the usual figures.
  4. Bore — the internal diameter, which tells you the pipe size it fits.
  5. Facing — is the gasket surface completely flat (FF) or does it have a raised ring around the bore (RF)?

Flange types we supply

Slip-on (SORF), weld neck (WNRF), blind, screwed, socket weld, lap joint, plate and puddle flanges, in carbon steel A105, SS 304/316, cast iron and ductile iron. IBR certified flanges available for steam service. See our flanges page for the full range, or ask for gaskets and fastener sets to match.

Flange questions we get asked

How do I identify an unmarked flange on site?
Measure three dimensions with a tape or vernier: the flange outside diameter, the bolt circle diameter (measure centre to centre between two diametrically opposite holes), and count the number of bolt holes. Those three numbers uniquely identify almost every standard flange. Compare them against the tables generated by this tool, or send us a photo with the measurements written on it.
Will a Table E flange bolt onto an ASA 150 flange?
No. Table E (IS 6392 / BS 10) and ANSI Class 150 have different bolt circle diameters and, in several sizes, different hole counts. They will not mate. This is one of the most common and most expensive errors on Indian sites — always confirm the standard of the existing flange before ordering the mating piece.
What is the difference between flat face and raised face?
A flat face (FF) flange has a completely flat gasket surface and is used with full-face gaskets, typically on cast iron equipment and low-pressure service. A raised face (RF) flange has a small raised ring around the bore that concentrates bolt load onto a smaller gasket area, giving a better seal at higher pressure. Never bolt a raised face steel flange directly to a flat face cast iron flange — the point loading can crack the casting.

Need a price today?

Send us your BOQ, drawing or item list on WhatsApp and get a written quotation the same working day. Ready stock for most sizes at our Delhi godown.

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