Special Hazards of Acetylene

  • Chemical Composition: Acetylene is chemically unstable which makes it very sensitive to conditions such as excess pressure, temperature, static electricity, or mechanical shock. Exposure to any of these conditions can cause it to undergo a violent, explosive decomposition reaction. If this reaction or ignition occurs within the torch base or supply hose it can propane back into the storage cylinder causing it to explode violently.
  • Ignition: Acetylene is very easy to ignite. In fact the energy from a static spark capable of igniting acetylene is lower than any other fuel gas except hydrogen! The static charge developed by walking across a carpet floor on a dry day can be 1700 time greater than that needed to ignite acetylene. When unburned acetylene gas is discharged from a torch, static electricity can be generated at the torch tip. If the tip comes in contact with a ground path, a static spark capable of igniting the gas can occur.
  • Burning: Acetylene burns at a very fast rate. The very fast burn rate can accelerate the rate at which pressure is generated in an explosion beyond what would occur for other fuels. This makes acetylene explosions more violent that those of other fuels.
  • Reactions: Acetylene forms explosive compounds with copper, brass, copper salts, mercury/mercury salts, silver/silver salts and nitric acid. Under no circumstances should acetylene gas come in contact with unalloyed copper, except in a torch.
  • Storage: Because of acetylene's unstable nature, it must be stored under special conditions. This is accomplished by dissolving the acetylene in liquid acetone. The liquid acetone is then stored in the acetylene cylinder, which in turn, is filled with a porous (sponge-like) cementitious material.
  • Acetone: Acetone is an EPA condemned chemical. The acetone contaminates the steel walls of the cylinder which creates a disposal problem. Disposal of condemned acetylene cylinders is very expensive not to mention extremely bad for the environment.
  • Right to Know: Acetylene and Acetone are both on the Right to Know Hazardous Substance list. EPCRA (Emergency Planning and Community Right o Know Act) Section 311-312 applies to any facility at which a hazardous chemical, as defined by the Occupational Safety and Health Act, is present in an amount exceeding a specified threshold.

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