Excavation - Potential Hazardous Consequences | AIChE

Excavation - Potential Hazardous Consequences

Last updated May 29, 2019 | Element: Potential Hazardous Consequences

Property Damage (Fire / Explosion) – While performing Hot Work in an Excavation

  • Creating an ignition source (flame, heat, sparks, non-intrinsically safe equipment, molten metal or direct flames) in a combustible atmosphere (flammable materials/vapors) leading to fire or explosion.
  • Impinging heat to surrounding process equipment, causing possible thermal expansion resulting in the release of hydrocarbons,
  • Arc from welding, possibly setting off fire detection / mitigation systems (i.e., deluge systems, alarms resulting in possible unit shut downs, etc.)
  • Interference with other simultaneous work in close proximity (e.g., work involving breaking containment and potential release of combustible gases while hot work is present.)
  • Hazards associated with welding equipment:
    • Damage and defective parts, if not replaced prior to start of the job
    • Improper grounding
    • Oxy-fuel equipment
      • If oxy-acetylene cylinders do not have sufficient material in the cylinders prior to start of the job, backflow can happen if one cylinder goes empty during operation which can cause:
        • A system pressure imbalance.
        • Mixing of oxy and fuel inside the hose.
      • Flashback caused by reverse flow of gas through the torch and back through to the hose, regulator and/or cylinder, potentially causing an explosion
  • Fire or explosion caused by ignition of flammable/combustible vapors/materials present in the excavation.

Personal Injury (Safety / Human Health)

  • Excavation cave-ins leading to entrapment and potential suffocation.
  • Falling into excavations leading to injury of death.