Tri Clamp Sizes

Tri-Clamp Sizing

When talking about Tri Clamp sizes, things get a bit complicated. There are 3 main global standards for Tri Clamp fittings. But first let’s consider the flange size and the tube size of any Tri Clamp fitting.

  • Flange size: the flange size (see picture above), will determine the compatibility with other Tri Clamp parts. Two flanges are connected together with a gasket and a clamp. Mismatched flange sizes cannot be connected together.
  • Tube Size: On the tube side of the flange, there are a wide variety of sizes available for each flange size. Tubes of different sizes can be connected together if they use the same flange size.

There are 3 different standards for sanitary Tri Clamp fittings: DIN, ISO, and BS (see table at the bottom of this page). Each is applied to a different standard of tube sizes. Although the tube sizes vary between specifications, the flange sizes are common to all three standards. For example, a BS 1.5″ Tri-Clamp uses the same 50.4mm flange size as the DIN DN40 Tri-Clamp. Within each standard, the various tube sizes will dictate the flange size.

In the homebrew world you will usually see 1/2″, 1.5″, or 2″ Tri Clamp parts advertised. This nomenclature is used solely to refer to their compatibility with other Tri-Clamp fittings! These parts may not actually have those same nominal inner diameters.

In our shop, our fittings are advertised as either 1/2″, 1.5″, or 2″ Tri clamp sizes. We are usually careful to mention the inside diameter of each fitting.

Tri-Clamp Specification Sample

Triclamp Specification Pipe Specification Sample Clamp Size Sample Tube Size
DIN 32676 (DIN 32676 Series A)
Metric – DIN 11850/10357 50,5 DN40
ISO 2852 (DIN 32676 Series B) ISO 1127 50,5 DN32
BS 4825 (DIN 32676 Series C, ASME BPE 2009) Imperial – ASTM A270 50,5 1,5″


We make every effort to provide specific information about which gaskets and clamps should be used for every fitting we sell in our shop. If you are still unsure, feel free to ask us before your purchase!