Identification of Fittings

Twin ferrule fittings are composed of four parts:

• Fitting body
• Front ferrule
• Back ferrule
• Nut

Info is written on the nut and body including manufacturer, material, size and type e.g.

• Swagelock – manufacture
• 316SS – material (normal 316L)
• Size – imperial or metric (metric fittings have a step machined on the nut and body. Imperial fittings do not)
• Must match fittings metric to metric imperial to imperial etc. (regarding valves Parker have it written on the side i.e. 12mm, the rest of the manufactures simply have mm with no actual sizing).
• Type – twin, ferrule, single ferrule etc.

Never take a fitting apart to check for the 2 ferrules always just look in.

The metal clamps are not recommended, as they can damage the tube by either biting into the tube when tightened, or wear down wall thickness by rubbing the tube walls when subjected to vibration.