Welding: Confined Space

Welding and cutting can be hot, hazardous jobs.  Trying to perform these jobs in a confined space, however, raises the risk. The problems welders encounter from a wide range of atmospheric hazards, such as fluorides, lead, zinc and toxic cleaning compounds, are only exacerbated by close quarters. That’s why it’s so important for site safety managers to ensure proper precautions are being taken by their welders who work in confined spaces.

An overview of the safety precautions that must be performed both before and during welding includes the following items:

1. Welders should inspect the area with gas detection instruments before they begin, to make sure it’s free of atmospheric hazards.
2. Confined Space / Hotwork permit should be raised and followed.
3. After taking gas detection readings, the space should be adequately ventilated with mechanical ventilators to prevent accumulation of toxic materials or possible oxygen deficiency. Vent all hollow spaces, cavities or containers, and take care to observe partitions or other barriers that might obstruct cross ventilation.
4. Finally, another atmospheric reading should be taken to make sure the space is ready for entry.
5. While occupied by personnel, the area should be ventilated with mechanical ventilators (but never oxygen) to prevent build-up of toxic materials or oxygen deficiency. The minimum ventilation rate is 2000 ft³ per minute, per welder, except where local exhaust hoods and booths are present, or when airline respirators are used.
6. Gas cylinders and welding equipment should also be left outside of the confined space. In addition, before the welding begins, heavy portable equipment mounted on wheels should be securely blocked to prevent accidental movement.
7. The welder should be provided safety belts and a lifeline, along with other required personal protective equipment.
8. A standby attendant, trained in rescue procedures, should be posted outside of the space. The standby attendant must maintain visual and verbal communication with the welder at all times.

There are still more safety precautions to take, however, concerning welding tasks.

For example, when arc welding is suspended for any substantial period of time (such as a lunch break), all electrodes must be removed from the holders.  The holders should be placed so that accidental contact cannot occur and machines should be disconnected from their power sources.  The same holds true for torch valves: when welding / cutting stops for a significant amount of time, the torch valves must be closed, the gas supply positively shut off at a point outside of the confined space and, where practical, the torch and hose removed from the confined space.

Respiratory Protection

Positive-pressure respirator (PPR) systems, or supplied air respirators with loose-fitting face-pieces, hoods or helmets and powered air-purifying respirators, are increasingly being regarded as valuable workplace productivity tools.  In addition to protecting workers’ eyes, head and face from airborne contaminants, this equipment can also guard against heat stress when combined with a cooling system.