Gas Outlet Styles - Medical Gas Info dot com

Medical Gas Outlet / Inlet Styles

This is probably the most confusing area in the medical gas industry. First, what is a keying style? Over the years, a number of different manufacturers have developed a means to dispense medical gases / vacuum easily and effectively from the centrally piped systems. These proprietary, gas specific, "keying styles" were patented and marketed under the original manufacturers name (hence the keying styles named for the company that originally developed them) Most of the keying styles were developed in the 1950's. Some 50 years later, long after the patents have now run out, you will be able to find numerous suppliers that offer the most popular keying styles on the market today.

It's in the best interest of the facility that all of the medical gas outlets / inlets are of the same keying style (see exception below*). You ask why? Here's why: The secondary equipment (flow meters, suction regulators, etc) all need to be "plugged into" the appropriate gas / vacuum outlet. In order to be able to be "plugged in," the secondary equipment must have the corresponding adaptor that fits into the wall outlet. If the secondary equipment does not have the correct style adaptor, it will not plug into the outlet / inlet and you will not be able to provide your patients with medical gas / vacuum. You do not want a portion of your facility with "X" keying style and the other portion of your facility with brand "B" keying style. If this were to happen, you could not plug in the secondary equipment from one portion of the facility to the other. Bottom line... no matter who the manufacturer of the medical gas outlet / inlet, make sure the keying style is the same!

*Here's the exception - there's always an exception - right? Any gas with a pipeline pressure higher than 80 psig or any gas outlet / inlet that is affixed to the ceiling, must be of the Diameter Index Safety System (DISS) keying style. If ceiling outlets are required, the connection at the ceiling must be DISS, but the connection at the user end maybe be of another "quick-connect" keying style. (The term "quick-connect" refers to all keying styles except DISS. They get their name from the ability of the care giver to quickly connect a piece of secondary to the appropriate gas outlet / inlet.)

Ohio keying style (also called Ohmeda keying style): gas specificity is accomplished by notches (similar to the hands on a clock) on the outlet face. The notches will vary in position based on the gas required.	click on image to enlarge
Schrader keying style: gas specificity is accomplished via "geo-metric indexing." (i.e. each gas has a unique shape and size)	click on image to enlarge
Chemetron keying style: gas specificity is accomplished by the position and shape of the access hole on the outlet face. The access hole will vary in position and shape based on the gas required.	click on image to enlarge
Puritan-Bennett keying style: gas specificity is accomplished via "geo-metric indexing." (i.e. each gas has a unique shape and size)	click on image to enlarge
Diameter Index Safety System (DISS) keying style: gas specificity is accomplished by gas specific threads. The thread diameter will vary based on the gas required.	click on image to enlarge