An Overview of Sanitary Fittings

clamp fittings

A lot goes into creating and maintaining a sanitary process, regardless of whether you are in food, beverage or pharmaceutical manufacturing.  The requirements to meet 3A, FDA and other sanitary guidelines are especially demanding.  Everything that the product touches, from pumps to tanks to piping, must be engineered to eliminate crevices that can create and harbor bacteria.  With that being said, let’s tip our hat to the sanitary fitting– quite possibly the most used piece of equipment in your plant.

Sanitary Fittings

fitting, gasket and tri-clamp

A sanitary fitting connects different sections of your process – piping to pumps to heat exchangers to tanks.  A fitting is typically defined as 2 ferrules, a gasket and a tri-clamp to hold them together.  A groove on the face of the ferrule provides a seat for the gasket.  The clamp provides the mechanical force to compress the gasket between the 2 ferrules.  The clamp is typically tightened by hand, but torque tools can be used to ensure a constant amount of force and eliminate over-tightening. 

 In sanitary processing, these fittings are preferred because they are easy to assemble, extremely easy to clean, leak-free and, when assembled correctly, have no small nooks or crannies to harbor bacteria.

The clamped union is the critical element for evaluating pipe pressure capacity.  Be certain your pressure ratings are for the union – not just the clamp.

Clamp Fittings

clamp fitting assortment

Clamp style fittings are most popular because they offer easy assembly and breakdown of process lines and equipment.  Clamp fittings are available in 304 and 316L stainless steel in sizes ½” through 12”. 

Weld Fittings

weld fittings

Weld fittings are used on permanent installations where process piping and equipment can be cleaned in place (CIP) and removal of the system components is not required.  Weld fittings are offered in nominal tube sizes from ½” through 8” in both 304 and 316L stainless steel. Uniform wall thickness for ½” through 3” sizes measures 0.065.  In 4” size, wall thickness measures 0.083.  In both 6” and 8” sizes, wall thickness measures 0.109.  Our weld fittings meet all 3A requirements.

Bevel Seat Fittings

bevel seat fittings

Bevel seat fittings are used on process equipment and piping to ensure rigidity of the system.  Bevel seat unions consist of a threaded bevel ferrule mated with a plain bevel ferrule. Both are offered in 304 or 316L stainless steel.  Bevel seat fittings meet all 3A requirements and are available in 1” through 4” sizes.

Gasket Selection

As mentioned earlier, tri-clamp fittings are made up of 2 ferrules, a gasket and a clamp.   Gasket selection is key to ensuring a leakproof connection.  The most common gasket materials are:

  • BUNA – nitrile rubber (NBR); a copolymer of butadiene and acrylonitrile
  • EPDM – ethylene propylene diene rubber
  • FPM – flourinated propylene monomer, commonly sold under the trade name Viton®
  • PTFE – polytetrafluoroethylene elastomer, commonly sold under the trade name Teflon®

For additional information on gaskets, check out our Elastomer Compability Guide and our Basic Elastomer Characteristics Guide.

Before tightening the clamp, make sure the gasket is seated properly into the seats of both ferrules.  Misalignment of the gasket is one of the main causes of leaks in tri-clamp fittings.

Check out our White Paper – An Overview of Sanitary Fittings – for more information or visit one of the links below.