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This post was last edited by Tianma Sky on 2017-4-13 07:46. Main properties and hazards of liquefied petroleum gas. (1) Flammability and explosiveness. Liquefied petroleum gas is highly flammable and can form an explosive mixture when mixed with air. The combustion of liquefied petroleum gas occurs in two forms: stable combustion and explosion. When liquefied petroleum gas leaks and continues to burn when exposed to fire, this phenomenon is called steady combustion. When liquefied petroleum gas leaks, it mixes with air to form an explosive mixture (with an explosion limit of approximately 2%–9%), and when exposed to a fire source, it explodes, usually generating a powerful shock wave and high temperatures. (2) Heavier than air. The gas relative density of liquefied petroleum gas is 1.5 to 2, and its specific gravity is 1.5 to 2 times that of air. Due to its high density, in the event of a leak, liquefied petroleum gas accumulates in low-lying areas or drifts across the ground; once it reaches an explosive concentration, it will explode upon encountering a source of fire. (3) Expandability. The saturated vapor pressure of liquefied petroleum gas increases sharply as the temperature rises, and its coefficient of expansion is also relatively high. It is generally more than 10 times that of water, and its volume can expand sharply by about 250 to 300 times after vaporization. Prone to frostbite. The boiling point of liquefied petroleum gas ranges from –6.3°C to –47.70°C. During the vaporization process, a large amount of heat must be absorbed, resulting in a sudden drop in local temperature; this can easily lead to frostbite in people, especially in accident situations. (4) Diffusibility Diffusibility refers to a substance’s ability to spread in air and other media. The diffusibility of gas depends on two main factors: density and diffusion coefficient. The greater the diffusibility of a gas, the faster the fire will spread, and consequently, the larger the area affected by the fire will be. (5) Low ignition energy. The ignition temperature of liquefied petroleum gas is approximately 430°C to 460°C, which is lower than that of other flammable gases; it requires less ignition energy, and a single spark is enough to ignite it. (6) It is toxic. Liquefied petroleum gas has low toxicity; at a concentration of 1% in the air, it is safe for humans to be in that environment for 10 minutes. When the concentration in the air reaches 10%, a person will ** after being in that environment for 2 minutes. (7) Chargeability. Liquefied petroleum gas is prone to generating static electricity during packaging and transportation; the faster the flow rate, the more likely static electricity will be produced. (8) Corrosivity. Liquefied petroleum gas is corrosive to containers, pipes, rubber hoses, seals, etc.