What is the maximum allowable pressure for free acetylene cylinders during storage or transport?

The maximum allowable pressure for free acetylene cylinders during storage or transport is 15 PSIG. This limit is established to ensure safety, as acetylene is a highly flammable gas that can become unstable at pressures exceeding this threshold. When stored in cylinders, acetylene is dissolved in a solvent to prevent it from reaching an unstable state. If the pressure in the cylinder exceeds 15 PSIG, there is an increased risk of the acetylene being released suddenly, which can lead to dangerous situations, including explosions or fires. This pressure regulation is crucial for safe handling and storage practices in both industrial and domestic settings. Understanding this limit is essential for anyone working with acetylene to maintain a safe working environment.