Confined Spaces - A 5 Step Safety Guide

Confined Spaces - A 5 Step Safety Guide

Published June 8, 2021

3 minute read

One man falls into a vat of slurry on a Norfolk farm. Two of his colleagues try to save him. All three are overcome by fumes and die.

In France, four workers are cleaning crystallized sugar from the sides of a 54-meter high storage silo, suspended on ropes. A load of sugar is discharged into the silo. Two workers die.

In Suffolk, a welder dismantling a ballast tank is overcome by fumes. His colleague tries to rescue him. He too is overcome. Both die.

All these are examples are of deaths in confined spaces. To avoid such tragedies, follow a five-step approach:


I/ Identify confined spaces:

If you think ‘I don’t have any confined spaces’ think again. Most workplaces have some areas that under some circumstances could be considered as a confined space.

As well as more obvious examples like tanks, silos, pits, trenches, pipes and sewers, consider tunnels, lifts, electrical cupboards, the space under your floor, and even loft spaces. Maintaining a register of confined spaces helps to manage the problem


II/ Eliminate work in a confined spaces:

If your confined space is under the floor, can you remove more floor panels so that the work is in the open? If work is in a cupboard or industrial oven, can you keep the doors open with a buddy outside to make sure it stays that way?

If you can’t prevent the space being confined, can you do the work from the outside? Can you use tools to reach in (without falling in)?

Longer term, invest in self‑cleaning silos and tanks to reduce ongoing cleaning costs. In the future, look out for the robots being developed to carry out inspection and repair work underground and inside vessels.


III/ If you can't eliminate, identify the hazard:

Think about the hazards already inside the space, and the hazards that the work will introduce.

In the accidents described, hazards include lack of oxygen, the presence of fumes and crushing or asphyxiation by solids. Confined space hazards also include fire and explosion, an increase in body temperature, chemical or thermal burns, electric shock and liquids. The risk of moving parts inside a space should also be assessed, with appropriate controls to switch equipment off, and keep it off.

Some work tasks will use up oxygen or create other gases. For example, inert gases used in welding to reduce the risk of fire can increase the risk of asphyxiation. Cleaning products, paint strippers and adhesives containing solvents can result in atmospheres which are unbreathable.


IV/ Select measures to manage hazards:

The control measures you need will depend on the hazards, but should cover these topics:

  • How will you make sure the air is breathable? Air might need to be tested at the start or monitored throughout. In some circumstances ventilation or a self-contained air supply might be needed.
  • How will people get in and out safely? If there is not fixed ladder, a portable means of access might be needed, like scaffolding or rope access.
  • How will people work safely in the space? Is additional lighting needed? Is the means of access also suitable for working from?
  • What hazards need to be controlled? Equipment might need to be shut down and locked out. New hazards must not enter the space during the work, so feed pipes might need to be closed off, as well as power.
  • Who else will be impacted? Permission to close-down equipment might need to be granted.
  • Is everyone competent? In all the accidents described, the people involved had not received specialist training for working in confined spaces. Competency is essential, so check that people assigned to a job have received training and know what to do, both to complete the work and in case of an emergency.

    Someone should be named to take responsibility for supervising the work, and for checking that all practicable controls are in place before work starts.


V/ Have a rescue plan:

Because accidents during confined space working can have fatal consequences, there should always be a plan in place for what to do if it goes wrong. You might have less than five minutes to get people to safety.

For some confined spaces the rescue plan might be a buddy outside the space who can open a door if it slams shut, or otherwise get help. Where people descend into a confined space winch and rope systems are common. In the cases above the additional deaths resulted from not having a rescue plan.



If you think this is a lot to remember, it is. This is why organizations that want to prevent accidents in confined spaces manage these stages with a permit process.

A confined space permit guides workers and supervisors through all the checks they need to make, all the equipment and protective clothing needed, all the permissions to be granted, and identifies who else needs to be told about the work. Only when the permit is signed off by the right people can the work begin.

Paper permit systems are common, but they can be difficult to manage. One of the underlying causes of the explosion on Piper Alpha in 1988 that killed 165 people was that a permit for some overnight maintenance was “lost” and people hadn’t been trained adequately on how the permit system worked.

Online permit systems provide a more reliable alternative to paper systems, particularly if they can link to existing online risk assessments. They are not a replacement for adequate training and safe systems of work, but if you’ve invested in systems and your people, a reliable permit system will keep them safe.

Author Laura Fitzgerald

Laura Fitzgerald is a Content Marketing Manager with EcoOnline. She has been writing about health and safety topics since 2017, with a focus on the areas of improving employee safety engagement and EHS legislation.

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