Confined Spaces

Safe Work Processes

What are confined spaces?

Many hazards are present within confined spaces. While the hazards are also common in regular workspaces, they can be more hazardous in a confined space due to the variability of the spaces and can result in severe injury or death.

Some of the most common hazards in confined spaces include:

Hazard Risk(s)
Oxygen (too little of too much)
  • Too little can cause brain damage
  • Too much increases riks of fire or explosion
Toxic gases and vapours (e.g. carbon monoxide, hydrogen sulfide, methane)
  • Dizziness, loss of consciousness, permanent damage to health, death
Explosions (e.g. combustible dust)
  • Fires or explosions
Biological hazards (e.g. mould, bacteria)
  • Mild reactions to severe immune reactions
Entrapment and engulfment
  • Buried or trapped by materials with empty spaces
  • Trapped or crushed when material is discharged
Moving parts of equipment and machinery
  • Physical injuries
Electrical Shock
  • Electrocution
  • Explosion
Substance entering through pipe
  • Drowning from liquids
  • Trapped, crushed or buried by solids
  • Being burned (e.g. steam)
Temperature extremes
  • Heat stress
  • Cold stress
  • Hearing loss


To effectively control the risks to these hazards, hazard assessments, entry procedures and rescue procedures must be established for each confined space.

Hazard assessments, entry procedures and rescue procedures must be prepared by a qualified person. A qualified person is one who has adequate training and experience in the recognition, evaluation and control of confined space hazards.

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What are the hazards in confined spaces?

A confined space is an enclosed or partially enclosed area with limited or restricted means of entry or exit. Although it is big enough for a worker to enter, it is not designed for someone to work in regularly. Examples of confined spaces include sewers, pits, boilers, tanks and hoppers.

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Who can enter confined spaces?

Only trained and authorized workers are to enter UBC confined spaces. Specific instruction and training must be given to workers who enter a confined space as well as any worker who is part of the work activity, such as a supervisor, standby workers and rescue personnel.

Workers must be instructed and trained as per the Occupational Health and Safety Regulation in the recognition of confined spaces, potential hazards of confined spaces, roles and responsibilities, atmospheric testing, ventilation, standby persons, rescue procedures, equipment, personal protective equipment, other precautions and coordination of work activities.

Prior to work starting, all workers involved in a confined space entry must be familiar with the site-specific confined space hazard assessment and safe work procedures and have all applicable documents available on site.

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How to get more information about confined spaces?

See UBC Confined Space Entry Program (PDF)

Additional UBC Resources:

If you have any questions on Confined Spaces at UBC, contact Safety & Risk Services (604-822-6732).

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