In an oxygen/acetylene torch system, acetylene becomes unstable when compressed in a gaseous state about how many psig?

In an oxygen/acetylene torch system, acetylene becomes unstable when compressed in its gaseous state at pressures around 15 psig. At this pressure, the risk of acetylene decomposing in an explosive manner increases significantly. Acetylene, when stored under pressure in a gaseous form beyond this threshold, can lead to a phenomenon called "explosive decomposition," which can present serious hazards during welding or cutting applications.

To safely use acetylene, it is typically stored in a dissolved state within a cylinder, combined with a solvent like acetone. This allows it to be utilized at higher pressures without the instability associated with gas at pressures above 15 psig. Therefore, maintaining the recommended pressure levels is crucial to ensure safe operations when using acetylene in welding equipment.