Which cylinder sizes utilize the PISS (Pin Index Safety System)?

The Pin Index Safety System (PISS) is specifically designed to prevent the accidental interchange of gas tanks with different gases. It utilizes a system of pins on the yoke that corresponds to specific gas types, thus ensuring that only the correct gas tank can be connected to the appropriate regulator.

In the context of cylinder sizes, PISS is used for E size cylinders and smaller. This is important because these sizes are typically used for portable applications, such as in ambulances and home healthcare. The PISS mechanism provides a safety measure in environments where many gases are used, helping to avoid potentially dangerous mix-ups.

Larger cylinders, such as those mentioned in other options like F, G, or H, utilize a different system called the AISS (American Industrial Standards) that employs a unique thread pattern for attachment and is not reliant on a pin system. This differentiation in safety systems is crucial for maintaining safety protocols when handling various gases.