Stainless Steel Threaded Fittings vs Compression Fittings: Which Should You Use?
Choosing the right fitting is about much more than simply connecting two sections of pipe or tube. Pressure, temperature, connection type, installation requirements and the wider system all need to be considered.
Two common options are stainless steel threaded fittings and stainless steel compression fittings. Both can provide dependable connections in industrial systems, but they work in different ways and are suited to different applications.
At Aston Fittings, we supply an extensive range of both threaded and compression fittings for demanding applications. So, what is the difference between them, and which should you use?
What Are Stainless Steel Threaded Fittings?
Stainless steel threaded fittings connect pipes, valves and other components using matching male and female threads. This provides a secure mechanical connection without the need for welding.
Depending on the application, different thread forms may be required, including BSPP, BSPT and NPT.
At Aston Fittings, our 150lb BSP 316 stainless steel screwed fittings include elbows, tees, sockets, nipples, bushes, plugs, unions and reducing fittings. For applications requiring different specifications, we also supply 3000lb fittings, including screwed and socket weld options. Our forged and wrought range is available to 3000lb and 6000lb ratings, with NPT, BSPT and BSPP thread options.
The wide choice of configurations makes threaded fittings useful across many industrial pipework systems, particularly where components need to be connected without creating a permanent welded joint.
What Are Stainless Steel Compression Fittings?
Compression fittings create a connection around the outside diameter of a tube. Rather than relying on the pipe itself being threaded, the fitting uses a ferrule system to grip the tube and create the required connection.
We supply both single ferrule compression fittings and twin ferrule compression fittings, with a wide variety of configurations available.
Our twin ferrule range includes 316 stainless steel unions, elbows, tees, bulkhead couplings and male and female stud couplings in metric and imperial sizes. Our single ferrule range also includes BSPP, BSPT and NPT connection options.
This makes stainless steel compression fittings a versatile option for tube and instrumentation systems.
What Is the Difference Between Threaded and Compression Fittings?
The biggest difference is how the connection is created.
With a threaded fitting, mating threads provide the mechanical connection between components. With a compression fitting, the ferrule system grips and seals around the tube as the fitting is assembled.
That difference can have a significant impact on which fitting is most appropriate for a particular system.
Which Is Easier to Install?
Both fitting types can provide connections without welding, but their installation requirements are different.
Threaded fittings require compatible thread types and sizes. BSPP, BSPT and NPT connections should not simply be treated as interchangeable, so it is important to check the system specification before choosing a fitting.
Compression fittings need to be correctly matched to the outside diameter of the tube and assembled according to the relevant fitting instructions.
Correct specification and installation are essential whichever option you choose.
Which Is Better for Your System?
A useful starting point is to consider exactly what you are connecting.
If a system primarily uses threaded pipework, valves or equipment with threaded ports, stainless steel threaded fittings may provide the most practical solution.
For tube and instrumentation systems, stainless steel compression fittings may be more appropriate. Compression fittings are available in a large number of configurations, allowing tubing to be joined, redirected, branched or connected to threaded equipment.
It does not always have to be a choice between one system and the other. For example, our twin ferrule range includes stud couplings that combine a compression connection with BSPP, BSPT or NPT threaded connections.
What About Pressure?
Pressure should always be considered against the specification of the individual fitting.
It is important not to assume that every threaded fitting or every compression fitting has the same capabilities. Our product range demonstrates just how much specifications can vary. Our forged and wrought fittings, for example, are available to 3000lb and 6000lb ratings.
Our compression fitting range also covers demanding applications, with Aston product information specifying compression fitting options for working pressures up to 6,000 psi.
Pressure is only part of the decision. Temperature, material, media, tube or pipe dimensions, connection type and the requirements of the complete system should all be considered.
Stainless Steel Threaded or Compression Fittings?
There is no single winner. The right fitting depends on the system.
Threaded fittings can be an excellent choice for compatible threaded pipework, valves and equipment, particularly where a conventional threaded connection is specified.
Compression fittings are particularly useful for tube and instrumentation systems where secure connections and a wide choice of configurations are required.
In some systems, the best solution may involve using both.
Find the Right Fittings for Your Application
At Aston Fittings, we manufacture and stock stainless steel tube and compression fittings alongside an extensive range of threaded fittings and other components from our Birmingham facility.
Whether you require twin ferrule fittings, single ferrule fittings, 3000lb fittings or another solution for your system, our team can help you identify the right components for your requirements.
Contact Aston Fittings today to discuss your application and find the right fittings for your system.
