Determination of a Confined Space and Risk Assessment

Determination of a confined space can be sometimes tricky, but is an essential step to ensure the safety of your workers. In this video blog, we will explore how you can determine whether an area is a confined space, and how to assess the risk related to this.

At the end of the blog, I have provided an example of a confined space identification tool, which you can download and use.

Watch the video below to hear Laurie discuss this topic:

In determining a confined space, the first thing we needed to determine is, is it enclosed or partially enclosed? The size of the space is not an issue here, it's just simply whether it is enclosed or partially enclosed. So, it could actually be a very large water tank with no top and that could be regarded as partially enclosed.

For the purposes of this video, we going to use an example of a storm water drain.





If a person was required to enter this drain to clean out a blockage of the pipes, would this be considered a confined space?

Looking at this particular confined space, you can see that it is partially enclosed. If the grid is removed and somebody enters, there’s no doubt that it is partially enclosed.


Is it designed or intended primarily to be occupied by a person?

For example, it could have poor ventilation, poor lighting, restricted entry points. It's not designed for a person to actually enter that point, and carry out working that area. And if we look again at the storm water drain, you can see that this is not actually intended to be occupied by a person.


Is the space intended to be a normal atmospheric pressure?

That's a fairly obvious one. This particular space is certainly at normal atmospheric pressure.


Does it contain or is it likely to contain an unsafe oxygen level?

It might be possible that there will be some gases in that particular drain that is going to displace the oxygen and reduce the oxygen level in that particular space.


Are there any contaminants, airborne gases, vapours or dust that may cause injury from a fire or an explosion?

It may be that there are gases that come down the pipes.


Does it have any harmful concentration of any other airborne contaminants?

For example, does the space when we climb in actually have sludge at the bottom that when we break releases some gases?


Can a person be engulfed?

In other words, could they drown? Could there be an inrush of water? Now, if they're going down into that space to remove a blockage, it is quite possible that once they've reduced the blockage, that water could flow and fill up that particular space, posing a risk of drowning, especially if the person has actually entered the pipe to go up the pipe to clean it.


You must ask yourself all of these questions when determining whether an area is a confined space. When we look at the confined space of a storm water drain, it could have unsafe oxygen levels. It could have harmful concentrations of airborne contaminants. And, it could involve engulfment.

Whilst we only need one for it to make it a confined space, it has three in this particular case, it basically has a tick in every box, so it would definitely be a confined space.


Risk Assessment: 

Once you've identified that a space to be entered is a confined space, you must then work through the risk assessment process to achieve the highest level of protection that is practicable.

Firstly, you can consider, can we eliminate the risk of somebody going into that confined space?

For example, if I’ve got a pump that needs servicing within a confined space, can I lift that pump to the surface to eliminate the need of the person actually entering the confined space?

There is various methods to do that. Often we can actually look at systems or processes to actually not only into the confined space and this would be the first thing that we would consider.

In our example of a storm water drain, obviously, there is a need to enter the space if we've got a blockage in the pipe, there's no other real way of doing it.



Minmise the Risk:

If we determine that we can't eliminate the risk then we need to minimize the risk. This can be done by considering:

-          Nature of the space

  • number, size, location of entry and exits
  • temperature
  • lighting

-          Concentration of oxygen or airborne contaminants

  • Level of oxygen 19.5% - 23.5%
  • Changes in oxygen or contaminant levels
  • Flammable atmosphere

-          Work and work method

  • Introduction of new, additional hazards
  • temperature
  • lighting

Other hazards could include falls, uneven surface, wet environment manual handling


One of the other things that we would have to consider in the risk assessment is, if an issue did occur, how are we going to get the person out of that space? If they had to crawl up the pipe a distance, how we actually going to rescue them, if there was an issue with that person?

It may not be as a result of a confined space; they may have a heart attack from the exertion. So, we need to consider how we're actually going to rescue them from that space.

Once we've been through the risk assessment process, then we can actually look at how we going to manage the risks in the confined space. And that's summarized by basically providing training to workers and the completion of a confined space entry permit.

So, what we have done is followed a systematic approach to identification and this must be documented. A good way to do this is to use a confined space identification tool.


Other videos in this series:

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