Hazards that may be present in confined spaces

Let us start this blog post by saying that enrolling in a confined space course with a Registered Training Organisation is crucial if you plan to enter and work in a confined space. If you are not sure what a confined space is and why one would need to enter a confined space in the first place, we recommend you to read this blog post before continuing to read this.

There are a range of hazards that may exist in confined spaces. A confined space course will teach you how to identify these hazards, what effect they can have and how to implement hazard controls. Here are some hazards that may be present in confined spaces:

Air normally contains 21% oxygen by volume. When the level of oxygen in a confined space are too low or too high, it can be a major hazard. When the oxygen level dips below 19%, the air is considered ‘oxygen-deficient’ and may cause asphyxiation. Lack of oxygen is a leading cause of death among people who work in confined spaces. A very low level of oxygen can damage the brain and cause the heart to stop after a few minutes. On the other hand, when the oxygen level is more than 23.5%, the air is ‘oxygen-enriched.’ Too much oxygen greatly increases the risk of fire or explosion in the confined space.

Dust, gases, fumes, mists and vapours are common hazards in the workplace air. These can seriously affect the health of workers. Hazardous dusts, gases, fumes, mists and vapours can occur in a confined space because of:

  • The work processes being done (i.e. spray painting)
  • Spills or leaks from pipes or machinery
  • Disturbance of materials (i.e. walking through a shallow liquid substance)
  • The storage or transfer of materials
  • Gases in stormwater drains and sewers
  • Chemical reactions between substances
  • Exhaust gases from pumps or other machinery being drawn into the confined space by ventilation fans
  • Residue left in confined spaces such as empty tanks and containers can cause a build-up of toxic or explosive gases

Inhaling some chemicals, such as solvents, can damage many parts of the body including the brain. Welding fumes, smoke and mists from spray painting are also serious respiratory hazards.

A flammable atmosphere usually results from vaporisation of flammable liquids, by-products of a chemical reaction, enriched oxygen atmospheres or concentrations of combustible dusts. An atmosphere becomes flammable when the required mix of fuel and oxygen comes into contact with an ignition source.

Confined spaces may also have physical hazards which workers may come in contact with such as:

  • Restricted Entry or Exit – In some cases, small entrances and exits make it difficult to rescue injured workers or to get equipment in or out of the confined space. In some instances, entrances and exits may be very large but inaccessible (i.e. opening high up in silos).
  • Engulfment – Materials such as plastic, sand, liquids, fertiliser, grain, coal and sewage pose a risk of engulfment.
  • Slip, Trip and Falls – The confined space may have a hatchway that is difficult to squeeze through and ladders for ascending or descending. As a result, you are at the risk of falling while getting into the confined space as well as while you are inside.
  • Falling Objects – In a confined space, there may be the danger of being struck by falling objects such as tools or equipment, particularly if access ports or workstations are located above workers.

Electrical shock can result from faulty extension cords, welding cables or other electrical equipment. Work conducted in metal enclosures or in wet conditions can be particularly dangerous.

Poor visibility increases the risk of accidents and makes it harder for a standby person to see a worker who may be in distress.

Noise produced in confined spaces can be particularly harmful because of reflection off walls. Noise levels from a source inside a small confined space can be up to 10 times greater than the same source placed outdoors.

Confined spaces should be fully drained or dry when entered. Spaces that are not fully drained or dry may pose a risk of drowning.

Having learned about all the different types of hazards associated with confined spaces, we are certain that you understand the importance of enrolling in a confined space course. Nara Training & Assessing is a Registered Training Organisation (RTO 4518) that offers confined space courses and many other civil construction and high risk training courses. For more information on Nara Training & Assessing’s confined space course and upcoming course dates, click here or call 0897224260.

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