Final answer:
Recovery cylinders must not be filled beyond 80% capacity to prevent over pressurization and potential explosions, especially when exposed to heat, as gas expansion can significantly increase internal pressure.
Step-by-step explanation:
To reduce the chance of over pressurization, heating, or explosion of recovery cylinders, they cannot be filled to more than 80% of their designed capacity. Overfilling a cylinder can lead to dangerous increases in pressure, especially when the cylinder is exposed to heat, which can cause the gas inside to expand. It's important to adhere to safety guidelines such as leaving air gaps, not tightly capping the tank to prevent overflow, and abiding by temperature limitations, as indicated by warnings like "Store only at temperatures below 120 °F (48.8 °C). Do not incinerate." For instance, a gas cylinder designed with a safety factor of 2 is meant to withstand pressures up to twice its normal operating pressure. If a cylinder designed to hold gas at 200 atmospheres heats up due to a fire, the pressure inside will increase, and the critical temperature at which the cylinder may fail needs to be calculated to prevent accidents.