Work Safe Oath Element Spotlight: Confined Space

What is a confined space? A confined space is any enclosed or partially enclosed space with restricted entry or exit that is not designed or intended for continuous human occupancy. The word ‘confined’ may suggest ‘small’, but not all confined spaces are. Some examples of confined spaces include tanks, access shafts, utility vaults, sewers, pipes, truck or rail tank cars, boilers, manholes, silos and storage bins. Ditches and trenches may also be a confined space when access or egress is limited. Some of the defining features of a confined space include:

■ It is not primarily designed or intended for humans except for the purpose of work.

■ It is enclosed or partially enclosed.

■ It has a restricted means of entrance and exit by way of location, size or means.

■ It has poor natural ventilation or hazardous atmosphere.

■ It may become hazardous due to design, materials or substances inside, or the work/activities being carried out inside.

What are the risks? Many confined spaces contain hazardous substances or dangerous conditions. Hazards and threats could include:

■ Poor Air Quality - Atmospheres with an oxygen content less than 19.5% (deficient) or more than 23% (enriched) are not safe.

■ Toxic Gasses - Hydrogen sulfide, carbon dioxide, carbon monoxide, smoke, ammonia, chlorine, etc. are all potentially deadly.

■ Flammable Atmospheres - A highly explosive atmosphere can be created when finely ground combustible materials such as grain, carbon, cellulose, fibers, plastics or flammable liquids are present.

■ Mechanical, Electrical or Physical Hazards - Examples include moving parts, structural hazards, noise, temperature and visibility.

■ Loose Materials that May Engulf or Smother - Shifting or collapse of bulk material, barrier failures, etc.

To effectively control the risks associated with working in a confined space, a Confined Space Hazard Assessment and Control Program should be implemented for your workplace.

What can we do to protect ourselves? The dangers and risks associated with confined spaces are not always obvious. All hazards must be identified and eliminated prior to entry, or all precautions must be taken for the safety of the person entering the confined space. Before entering any confined space:

■ Conduct a risk assessment, and know the practices and procedures.

■ Ensure that adequate atmospheric testing and monitoring is being conducted with an approved air quality monitor.

■ Determine the proper personal protective equipment required.

■ Ensure a competent watch person is present with an effective emergency response plan. The watch person must always have communication with the emergency response team and the person in the confined space.

Above all else, ensure that all personnel involved in the confined space process are competent to do the job safely. Many workers are injured and killed each year while working in confined spaces. An estimated 60% of the fatalities have been among the would-be rescuers. Unless you are trained in confined space hazards and how to control them, never enter a confined space.