A Confined Space
- Is large enough and so configured that an employee can bodily enter and perform assigned work; and
- Has limited or restricted means for entry or exit; and
- Is not designed for continuous employee occupancy.
- Within a confined space there is a serious risk of death or injury from hazardous substances or conditions. Some Confined Spaces are easy to identify (storage tanks, silos, enclosed drains, sewers, etc). Others are less obvious, but equally dangerous (open-topped chambers, vats, trenches, ductwork, and unventilated or poorly ventilated rooms).
The Dangers in a Confined Space
- Lack of oxygen.
- Poisonous gas, fumes or vapors.
- The unexpected rush of liquids, gases or solids into a space.
- Fire and explosions (from flammable vapors, excess oxygen, etc).
- High concentrations of dust.
- Extreme heat leading to dangerous increases in body temperature.
- Mechanical or physical hazards
- Loose materials that can engulf or smother
Permit or Not
- Confined spaces are categorized into two main groups: non-permit and permit-required. If a hazard exists or has the potential to exist, a written permit is required for entry. Assume all confined spaces are permit required.
- Although the danger in a confined space may be obvious, such as a mechanical hazard, the type of danger often is not. For example, a confined space with sufficient oxygen might become oxygen-deficient once a worker begins welding or performing other tasks.
Workers must be trained to work in all confined spaces. This talk is not sufficient training for any confined space work.
- Can the work be done another way?
- Make use of safe systems for working inside such spaces.
- Harness workers to lifelines running to the outside of the space.
- In any confined space use mechanical ventilation to improve airflow.
- Use non-sparking tools and specially protected lighting where flammable or potentially explosive atmospheres are likely.
- Never attempt to add oxygen into a confined space. This can greatly increase the risk of a fire or explosion.
- Pre-read the Toolbox Talk. Your comfort level and confidence will be higher if you know your topic.
- Discuss related tasks, work areas or events that make the Toolbox Talk relevant to your job site.
- Involve the workers by asking questions and input that drives discussion.
Questions for Discussion
- What confined spaces do we have around our workplace?
- Which are permitted? Can any of the hazards within the confined space be removed?
- Has the air been tested? Is our ventilation system adequate?