🔍 Key Concepts

• Properties of acetylene gas under pressure • Design limits of acetylene cylinders and regulators • Differences between flow rate hazards and pressure/instability hazards

💭 Think About

• Think about what physically changes in acetylene when the pressure is increased above 15 psig—does it affect the container parts, the gas itself, or the rate it is used? • Which of the options describes a fundamental safety limit of acetylene as a substance, rather than a device (like a valve or plug)? • Ask yourself: is the 15 psig limit mainly about protecting hardware, or about preventing a dangerous chemical/physical condition in the gas?

✅ Before You Answer

• Identify which choices are about hardware components (valves, plugs, cylinders) versus the gas properties. • Recall that acetylene is known to be chemically unstable at higher pressures—consider which answer reflects that concept. • Verify which choice explains a reason for the pressure limit itself, not just a consequence that might happen afterward.