# Instrumentation Fittings (Double and Single Ferrule) — Hydraulic and pipe connection type identification

For Instrumentation Fittings (Double and Single Ferrule), governing standard is Instrumentation; region of origin is Instrumentation Fittings; thread type (tapered or parallel) is UNEF (extra fine); seat or flare angle is inner cone; seal method is The seal is made between the front ferrule and the cone. The tubing is held in place by the swaging action caused by the tightening of the nut, which forces the front and back ferrules to bite into the tubing, firmly holding it in place, recorded from its source on 2026-08-13.

- **Connection type:** Instrumentation Fittings (Double and Single Ferrule)
- **Governing standard:** Instrumentation _(verified: appears in the quote below)_
- **Region of origin:** Instrumentation Fittings _(our reading, not quoted from the source)_
- **Thread type (tapered or parallel):** UNEF (extra fine)
- **Seat or flare angle:** inner cone _(verified: appears in the quote below)_
- **Seal method:** The seal is made between the front ferrule and the cone. The tubing is held in place by the swaging action caused by the tightening of the nut, which forces the front and back ferrules to bite into the tubing, firmly holding it in place. _(verified: appears in the quote below)_

## What the source says

> Double and Single Ferrule Instrumentation Fittings are widely used in fluid or gas transfer applications such as refineries, chemical plants and food processing plants. The male end of a double-ferrule instrumentation fitting has a recessed counter-bore which matches the tube OD being used, plus an inner cone. The seal is made between the front ferrule and the cone. The tubing is held in place by the swaging action caused by the tightening of the nut, which forces the front and back ferrules to bite into the tubing, firmly holding it in place.

## Source

- https://brennaninc.com/connection-types/

Last verified: 2026-08-13. Review by: 2028-08-12.
Part of [Hydraulic and pipe connection type identification](https://referencesource.org/hydraulic-pipe-connection-types/).