For Best Results, Simplify Your Compression Fitting Installation

For Best Results, Simplify Your Compression Fitting Installation

In process, motion control and instrumentation applications, improper installation of connections for fluid delivery systems is one of the leading causes of leaks and other costly problems for industrial operators. That’s why taking steps to ensure a pain-free, secure connection – and learning how to identify and avoid potential problems ahead of time – is critically important.

Double-ferrule compression fittings, which have been the industry standard for more than 80 years, are frequently susceptible to incorrect installation. This is due to the simple fact they are often recommended as replacement parts because they are compatible with fittings many plants already have on hand.

While double-ferrule fittings can provide a reliable connection when installed properly, their design poses some issues that can make installation a challenge:

  • Parts are small and can be easily dropped or lost.
  • There are more than 11 different ways to assemble, reassemble or connect this type of compression fitting, but only one is correct.
  • The rear ferrule is typically the most common cause of performance issues due to being installed backwards or missing altogether.

Once the installation error has been identified, fixing the system can be time-consuming and labor-intensive, requiring several steps to rectify the situation:

  • Troubleshoot and diagnose the problem.
  • Obtain a new compression fitting or other components from stores.
  • Obtain new tubing from stock.
  • Return to installation point or shop.
  • De-pressurize the system.
  • Remove existing tubing and/or compression fitting.
  • Measure, cut, debur, mark and bend tubing.
  • Install replacement compression fitting into port.
  • Insert tubing and make-up compression fitting.

Single-ferrule compression fittings offer the same effectiveness as double-ferrule compression fittings, plus the added benefits of simplicity and ease of use. Because these compression fittings rely on only one ferrule, they have fewer interior parts. This results in only three assembly combinations, two of which (missing ferrule and backwards ferrule) are obviously incorrect to the assembler and can be easily avoided.

This simplicity significantly minimizes:

  • Dropped, lost or damaged ferrules during installation.
  • Post-installation compression fitting replacement due to missing/incorrect part orientation or damage to the ferrule body-sealing surface.
  • Replacement due to galling of body threads.

Single-ferrule compression fittings are also designed to eliminate the need for an additional seal point between the front and rear ferrules, which increases reliability by eliminating a potential leak point in each coupling. This type of compression fitting also absorbs incoming vibration by gripping the tube at the front, while the rear of the ferrule compresses the tube and shields the grip area with the compression action.

When it comes to compression fittings, no one product can solve every problem necessary to maintain consistent pressure. Plant operators should consider all available options and determine which fitting design will provide the best outcome in terms of ease of installation, use, maintenance and durability.

Fluid Flow provides a wide variety of both single- and double-ferrule designs allowing industrial operators to choose components that will help them maximize the efficiency and performance of their compressed air and fluid handling systems.

Click here to learn more about CPI-Series Single Ferrule Compression Fittings from Parker Hannifin. To learn more about the benefits of single-ferrule compression fittings, read our white paper, “How Compression Fittings Can Make or Break a Compressed Air System.” For more information on our instrumentation components, visit




The Fluid Flow Products team is on standby, ready to assist you with compressed air and fluid processing solutions that are unmatched in the industry. From technical expertise you can trust to industrial equipment from leading manufacturers, we offer access to everything you need to drive the productivity of your operation.

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