Quick Disconnects (LP) - High Flow

Swagelok makes the QC6 quick-connect system of high-flow fittings for the instrumentation industry where it is primarily used with liquids. The technical diving community as begun to adopt the QC6 system for mission critical quick-connect SCUBA applications where it is used with gases; it is particularly seen in rebreather applications. Compared to other high flow quick connect systems in scuba the QC6 system has some advantages: The QC6 stem is available with a double-end shutoff (DESO) feature indicated by a red color collar that blocks flow from both the body and the stem while they are not connected. The QC6 system can be reliably coupled and uncoupled while pressurized up to 250 psi. QC6 also has a relatively small inclusion volume of less than 1 cm³ when the fittings are coupled together while underwater.

The QC6 system from Swagelok does not natively offer any compatibility with the fittings commonly seen in SCUBA low-pressure gas applications meaning either aftermarket adapters are required and/or the QC6 fittings themselves must be aftermarket machined, which raises safety and reliability concerns. Considering the adapters, the QC6 solution is significantly larger and longer than other systems. Also, the QC6 system from Swagelok is considerably more expensive than other quick connect systems typically seen in diving applications; a single set of stainless steel QC6 body and DESO stem with adapters and/or aftermarket modifications is going to cost $200.00 or more. Regardless of the QC6 small inclusion volume, because using any quick-disconnect system underwater for gas switching is unavoidably going to allow some contamination in to the gas line, we do not recommend QC6 routine use for gas switching.