Environmental, Health and Safety Services

Confined Space Hot Work

If a permit-required confined space has been declassified to a non-permit space according to the Confined Space Program, welding and cutting is allowed provided the following conditions are met:

  • A Hot Work Permit has been issued in accordance with the Fire and Life Safety Program.
  • Tanks or equipment that have previously contained flammable gases, vapors, liquids, or dusts with air have been properly drained, cleaned, and prepared.
  • When arc welding is to be suspended for any substantial period of time, such as during lunch or overnight, all electrodes shall be removed from the holders and the holders carefully located so that accidental contact cannot occur and the machine be disconnected from the power source.
  • When gas welding or cutting, the torch valves shall be closed and the gas supply to the torch positively shut off at some point outside the confined space whenever the torch will not be used for a substantial period of time, such as during lunch or overnight. Where practicable, the torch and hose shall also be removed from the confined space.
  • Welders shall place welding cable and other equipment so that it is clear of passageways, ladders, and stairways.
  • Gas cylinders and welding machines shall be left outside of the confined space. Heavy portable equipment (outside of the space) mounted on wheels shall be securely blocked to prevent accidental movement.
  • Where a welder must enter a confined space through a manhole or other small opening, means shall be provided for quickly removing him/her in case of emergency. When safety harnesses and lifelines are used for this purpose, they shall be so attached to the welder's body that his body cannot be jammed in a small exit opening. An attendant with a preplanned rescue procedure shall be stationed outside to observe the welder at all times and be capable of putting rescue operations into effect.
  • After welding operations are completed, the welder shall mark the hot metal or provide some other means of warning other workers.
  • All welding and cutting operations conducted in confined spaces shall be adequately ventilated to prevent the accumulation of toxic materials or possible oxygen deficiency. This applies not only to the welder, but also to helpers and other personnel in the immediate vicinity. All air replacing that withdrawn shall be clean and respirable.
  • Mechanical ventilation shall be provided when welding or cutting in confined spaces. Local exhaust ventilation is required when welding or cutting involves metals containing lead, beryllium-containing base or filler metals, cadmium-bearing or cadmium-coated base metals, or mercury-bearing materials (including paint).
  • In circumstances for which it is impossible to provide such ventilation or in areas immediately hazardous to life, NIOSH-approved positive pressure respiratory protection must be used. Contact EHSS for approval to enter the space and guidance on appropriate respiratory protection selection, use, and practices.
  • Oxygen shall never be used for ventilation.
  • Degreasing and other cleaning operations involving chlorinated hydrocarbons shall be so located that no vapors from these operations will reach or be drawn into the atmosphere surrounding any welding operation.
  • First aid equipment shall be available at all times.