Intermix & Interchange
INTERMIXING & INTERCHANGING OF TWO FERRULE TUBE FITTINGS. IS IT SAFE?
INTERMIX
The combination of two or more manufacturers’ sub-components (nut, front & rear ferrules and body) to form a tube fitting.
INTERCHANGE
The swapping of pre-swaged nut & ferrules from one manufacturer into the fitting body of another manufacturer.
THE INDUSTRY PERSPECTIVE
Numerous manufacturers of Tube fittings claim that their fittings can be intermixed and/or interchanged with those of other manufacturers without compromising performance, reliability or safety.
This is not the case! A published independent research document known as the Seymour report (Journal of Engineering Design, Vol. 10, No. 4, 1999) warns against the dangers of intermixing and interchanging of manufacturer's tube fittings and condemns it as an unsound engineering practice.
You can read a summary of the document by following the link
THE HSE STANDPOINT
The HSE states in their Loss Of Containment Manual that
"it is not permissible to interchange sub-components of different designs or types of Tube Fittings.”
SWAGELOK'S VIEW
NEVER INTERMIX/INTERCHANGE FITTINGS
It is a poor practice to intermix/interchange tube fittings from different manufacturers.
There is no industrywide commercial design standard for fittings, meaning:
• Each manufacturer follows its own standards and processes
• An intermixed/interchanged fitting is essentially a new untested design
• The user accepts full responsibility for performance and outcome
• Voids Swagelok's Limited Lifetime Warranty
SUMMARY
Avoid possible performance issues, such as:
Leaks, Extra Cost and Safety Concerns