Focus on SMS connections

Swedish SMS Fittings are among the most widely used fittings in the food, chemical and pharmaceutical industries. They consist of 4 parts:

  • A male threaded nose, with a round thread, which accommodates the seal
  • A smooth, flat-faced weld-on part
  • A seal with a square or L-shaped cross-section
  • A round notched and chamfered nut

SMS Fitting

SMS diameters are usually given in mm, according to the metric standard, but they can also be found in inches (see table of correspondences). They are available from DN25 to DN104, and machined in 316L stainless steel.

SMS fittings use semi O-rings, square section seals or L-section seals. The use of an L-section gasket improves the hygiene of the fitting by eliminating the annular retention area. The seals offered by Sofra Inox are FDA and 3A compliant.

They are used in installations subject to moderate pressure (30 bar max).

SMS fittings are easy to install but are not designed for regular disassembly, as the alignment of the pipework must be perfect.

Diameter matching

DN (mm) 25 38 51 63.5 76 104
DN (inches) 1" 1"½ 2" 2"½ 3" 4"


See our range of SMS fittings