confined space

How to ensure safe work in a confined space

Knowing how to mitigate the risks involved in working in a confined space is vital.
Wednesday, May 18, 2022

Working in the janitorial industry can involve working in a confined space, and that certainly comes with its own risks.

A confined space is fully or partially enclosed and not primarily designed or intended for continuous human occupancy. It has a limited or restricted entrance or exit, or a configuration that can complicate first aid, rescue, evacuation, or other emergency response activities.

The major risk factors in a confined space tend to be its design, construction, location or atmosphere, the materials or substances in it, the work activities being carried out in it, or the mechanical process and safety hazards present.

Confined spaces can be below or above ground – you can find them in almost any workplace. And, despite the name, they aren’t necessarily small.

There are examples of confined spaces in many different industries. In agriculture, for example, there are silos, vats, hoppers, utility vaults, tanks, manure pits, and water supply towers. Municipal waterworks have sewers, pipes, access shafts, boilers, and pump stations. In transport, think of truck or rail tank cars, barges, shipping containers and aircraft wings. A ditch, well, or trench may also be a confined space when access or exiting is limited, although they are open to the air above.

Identifying and controlling hazards

Any hazard found in a regular workspace can also be found in a confined space. But in a confined space, workers are more at risk. There is often an insufficient amount of oxygen for a worker to breathe or toxic gases that could make the worker ill or cause them to lose consciousness.

Simple asphyxiants, including argon, nitrogen, or carbon monoxide, are gases which can displace oxygen in the air. Low oxygen levels (19.5 per cent or less) can cause symptoms such as rapid breathing, rapid heart rate, clumsiness, emotional upset, and fatigue. As less oxygen becomes available, nausea and vomiting, collapse, convulsions, coma and death can occur. Unconsciousness or death could happen within minutes of exposure to a simple asphyxiant.

Confined spaces are also at an increased risk of an explosive or flammable atmosphere due to flammable liquids and gases and combustible dusts which, if ignited, would lead to fire or explosion.

Other hazards that might be present include process-related hazards such as residual chemicals or the release of contents of a supply line. Workplaces also need to consider physical hazards like noise, heat and cold, radiation, vibration, electrical, and inadequate lighting.

In addition, there are many safety hazards, ranging from moving equipment parts to structural hazards that could lead to engulfment, entanglement, slips, or falls. A barrier failure could result in a flood or release of free-flowing solids or liquids. Biological hazards include viruses, bacteria from fecal matter and sludge, fungi, and moulds.

An error in identifying or evaluating potential hazards in a confined space can have more serious consequences, as their conditions are often extremely dangerous or life-threatening.

For example, the entrance might not allow the worker to get out easily should there be a flood or collapse of free-flowing solid. Self-rescue may not be possible, and rescue of the worker could be difficult. An estimated 60% of fatalities that happen in confined spaces are would-be rescuers. The interior configuration of a confined space does not typically allow easy movement of the people or equipment within it. Conditions can change very quickly, and natural ventilation alone will often not be sufficient to maintain breathable quality air.

Preparing to enter a confined space

Before a worker enters any workspace, employers should determine if it is a confined space. The next question to ask is: Is it absolutely necessary that the work be performed inside the confined space? In many cases where there have been deaths in confined spaces, the work could have been done outside of it.

A trained person should identify and evaluate all the existing and potential hazards within the confined space before any workers enter it. Evaluate activities both inside and outside, including testing the air from outside, before entering. Care should be taken to ensure that air is tested throughout the confined space – side-to-side and top to bottom.

Continuous air monitoring may also be needed, especially in situations where a worker is in a space where atmospheric conditions have the potential to change (e.g., broken or leaking pipes or vessels, work activities creating a hazardous environment, or when isolation of a substance is not possible). A qualified worker using detection equipment that is appropriate and calibrated according to the manufacturer’s instructions should test the air quality. Sampling should show that oxygen content is within safe limits, a hazardous atmosphere is not present, and ventilation equipment is operating properly. The opening for entry into and exit from the confined space must be large enough to allow the passage of a person using protective equipment.

Because of the elevated risk of injuries and fatalities, it is absolutely crucial that organizations have a well-developed confined space program. This program should outline requirements for risk assessments and hazard control, safe work procedures, worker training, entry permitting process, air testing, emergency response, record keeping, and program review. There should also be a description of the roles and responsibilities of each person or party, including the employer, supervisor, workers, attendants, and emergency response team.

Requirements for entering confined spaces can vary by jurisdiction, so be sure to review the applicable legislation before proceeding.

Source: Canadian Centre for Occupational Health and Safety

One thought on “How to ensure safe work in a confined space

  1. I’m glad you described the importance of identifying a confined space’s hazards before your crew enters it. I heard that my cousin needs to enter a confined space next week, and my family’s very worried about his safety, so I’ll make sure he reads your article immediately. I appreciate your insight on preventing fatalities when working in confined spaces.

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