Pin Index Safety System

The Pin Index Safety System, or PISS, is a safety system that uses geometric features on the yoke to ensure that pneumatic connections between a gas cylinder and a machine that uses pressurized gases are not connected to the wrong gas yoke. This system can be seen on an anesthesia machine.

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Daily Sensitivity Test

Each gas cylinder has a pin configuration to fit its respective gas yoke. Refer to the figure on the right; units are in millimeters.

• O₂: 2-5
• N₂O: 3-5
• Air: 1-5
• CO₂: 1-6
• Heliox: 2-4

Standards

• International (ISO) and European (CEN) Standard

• EN ISO 407 : Small medical gas cylinders - Pin-index yoke-type valve connections

References

• http://www.udmercy.edu/crna/agm/03.htm for pin positions.