Tight Squeeze?

Working in confined spaces can be much more hazardous than regular workspaces for a variety of reasons. Sadly, many workers are injured and killed each year while working in confined work environments, with would-be rescuers making up an estimated 60% of fatalities overall. Planning, preparation and control are key elements in minimizing risk.

What is a Confined Space?

Generally speaking, a confined space is any enclosed or partially enclosed area that can represent a risk for the health and safety for anyone entering. They can be above or below ground and can be found in many different workplaces. And despite the name, confined spaces aren’t necessarily small. Examples would include silos, vats, hoppers, utility vaults, tanks, sewers, pipes, access shafts, truck or rail tank cars, boilers, manholes and storage bins. Ditches and trenches may also be considered to be confined spaces when access or exit routes are limited.

Typical Hazards

All hazards found in regular work environments can also be found in a confined space. However, the risk can be amplified greatly due to limited access and the very nature of the area being enclosed.

Hazards in confined spaces can include:

  • Poor air quality or lack of oxygen
  • Exposure to chemical or biological hazards
  • Risk of fire or explosion due to flammable gases, liquids or combustible dusts
  • Excessive noise
  • Physical safety hazards such as moving equipment parts, structural hazards, entanglement, slips & falls
  • High levels of radiation
  • Temperature extremes including atmospheric and surface
  • Shifting or collapse of stored bulk material
  • Barrier failure resulting in a flood or release of soil or rock
  • Uncontrolled energy release including electrical shock
  • Low visibility

Controls & Response

Many factors need to be evaluated when looking for hazards in a confined space. Any error in identifying or evaluating potential hazards can have serious consequences. The traditional hazard control methods found in regular worksites can be applied to confined areas in most cases. These include engineering controls, administrative controls and personal protective equipment (PPE). Engineering controls are designed to remove the hazard while administrative controls and personal protective equipment try to minimize the contact with the hazard.

Assessment & Procedures

To effectively control the risks associated with working in a confined space, a Confined Space Hazard Assessment and Control Program should be implemented for each workplace. These are typically prepared in consultation with local and regional occupational health and safety experts and officials.

Before venturing into program development, make sure to review the specific regulations that apply to your type of workplace. All regional or municipal jurisdictions have regulations dealing with confined space entry, and these can vary slightly from jurisdiction to jurisdiction. Based on the assessment, required compliance and recommendations, a comprehensive operational plan may then be prepared and put into place.

Entry Programs

It is standard for employers to prepare and implement a confined space entry program before any worker enters one of these areas. If the confined space in-question cannot be made safe for workers by taking the necessary precautions, then workers should NOT enter the confined space until all requirements of the overall safety program have been met.

Program elements may include (but not limited to):

A complete listing of each confined space or group of similar spaces with the workspace.

A hazard assessment of each of these spaces.

Written safe work procedures for entry into, and work within the confined space, that address (where applicable):

  • A clear assignment of responsibilities
  • An identification and entry permit system
  • Entry lockout & security
  • Safety verification and testing
  • Cleaning, purging & venting
  • Ventilation
  • Standby personnel
  • Rescue procedures
  • Lifelines, harnesses and lifting equipment readiness
  • Personal protective equipment and other precautions
  • Coordination and supervision of work activities
  • Ongoing monitoring


Every worker who operates in a confined space, their supervisors, those working in the immediate area and rescue workers must all receive adequate training in:

  1. he recognition of hazards associated with confined spaces.
  2. Training to be able to safely perform the assigned duties for a specific confined space.
  3. Rescue operations.

On-site rescue procedures should be practiced on a regular, scheduled basis and include first-aid, CPR and use of the specific rescue equipment required. Hands-on training should become part of the regular program, in addition to a ‘buddy system’ for new workers where they are paired with someone more experienced for an initial period of time.

Ventilation / Air Quality

Confined spaces may contain hazardous air contaminants that may be colourless, odourless and that can only be detected with testing. Air testing should be conducted by qualified personnel only, and with properly calibrated sensors. It may also be necessary to test on an ongoing basis, as the atmosphere may change over time and become more hazardous. It is also important to test the entire workspace from top-to-bottom and side-to-side to ensure a completely safe work environment. The defined hazard level, type of hazard and use of mechanical ventilation should be recorded and also noted on each entry permit.

Natural ventilation (existing air currents) is normally not reliable or sufficient enough to maintain the air quality within a confined space. Mechanical ventilation is usually necessary to maintain the atmosphere at acceptable levels. If mechanical ventilation is provided, there should be a warning system in-place to immediately notify workers in the event of a hazard or a failure in the ventilation equipment.

Fire / Explosion

Another danger of working in confined spaces is the risk of fire or explosion due to the ignition of flammable gases, vapours or dusts. Work where a flame is used or a source of ignition may be produced (hot work) should not normally be performed unless certain steps are taken to ensure a safe work atmosphere. These would include:

  • Complete testing of the atmosphere within the confined workspace and approved access through the entry permit process only
  • The removal or purging of all flammable gases, liquids and vapours
  • The provision of mechanical ventilation
  • Making sure that the oxygen content in the confined space is not enriched beyond acceptable levels
  • Any surfaces coated with combustible materials are cleaned or shielded to prevent ignition
  • Fuel sources such as gasoline, propane and their containers should not be taken into confined spaces unless absolutely necessary and are approved/authorized through the specific Confined Spaced Program
  • Ensuring that welding equipment, hoses and tanks are in good condition
  • Where appropriate, using spark resistant tools and making sure that all equipment is grounded properly

Energy & Mechanical Hazards

All potentially hazardous energy sources such as electrical, mechanical, hydraulic, pneumatic, chemical, or thermal must be de-energized and locked-out prior to entry to the confined space so that equipment cannot be turned on accidentally.

Additionally, all pipes should be physically disconnected or isolation blanks bolted in place to prevent any accidental flow. Closing valves is not sufficient.


To reduce the risk of engulfment by liquids or free-flowing solids within a confined space, one of two conditions would need to be met.

  1. All material is physically removed from the space so that there is no chance at all of an accident due to shifting, collapse or overflow.
  2. An adequate barrier or series of barriers is present to prevent any material from entering the workspace in the event of an incident. This could include vats, silos, storage containers, trenches etc.

Working Solutions

In addition to the controls listed above, there are a variety of other workplace tools and equipment that help to make work within confined spaces safer.

Personal Protective Equipment (PPE) suitable for the specific environment and associated hazards including protective clothing, gloves, boots, helmet, face, eye and hearing protection.

Respiration systems for working in unsafe atmospheres and as back-up in the event that an escape or rescue is required.

Access, exit and rescue rigs including hoists, winches, tripods, mounts, brackets, harnesses, cables, pulleys and safety lines.

Ventilation equipment such as vents, fans, blowers, connectors and flexible ducting.

Rescue & resuscitation equipment including defibrillators, backboards, neck braces and approved first aid supplies.

Security devices such as guardrails, rescue ladders, lockout kits and warning signs.

There’s a lot to consider when it comes to confined space safety, but it’s all worth it when you consider the potential for danger to workers on a daily basis.

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