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.

Additional recommended knowledge

Essential Laboratory Skills Guide

Daily Visual Balance Check

Weighing the right way

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.