Why should acetylene cylinders be stored in an upright position?

Acetylene cylinders should be stored in an upright position primarily to prevent acetone from escaping. Acetylene is often dissolved in acetone to stabilize it under pressure, as acetylene is highly volatile and cannot be stored in its gaseous form alone at pressures higher than 15 psi. When the cylinder is upright, the acetone remains in the bottom, allowing for a safe and stable environment for the gas to be released as needed. If the cylinder is tipped or laid on its side, acetone could escape along with the gas, potentially leading to dangerous situations, including inconsistent gas delivery and increased risk of flammability.

The other options, while they might touch on related safety or practicality issues, do not directly address the primary reason for storing acetylene cylinders upright. Enhancing the safety of the working environment could be a broader concept, but it does not capture the specific mechanical and chemical reasons tied to acetylene storage. Similarly, keeping the cylinders cooler or ensuring easy transportation do not directly relate to the containment and stabilization of acetylene gas itself within the cylinders.