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Confined Space Entry Monitors: Are you using the right monitor?

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Confined space entry gas monitors are used on a regular basis across almost all industries; be it construction, demolition, facilities maintenance, land remediation or utility services. However, the misnomer, ‘confined space entry monitor’ or ‘confined space atmosphere tester’ is often used; but do we know what we are truly testing for?

Your run of the mill ‘confined space entry monitor' will monitor for the absence or presence of methane gas at explosive levels, oxygen, hydrogen sulfide and carbon monoxide; which is great if those are the only risks present. Nevertheless, we need to probe a little bit deeper to understand what we actually need!

When we monitor a confined space atmosphere we need to determine both prior and during occupation of the confined space, whether there is enough oxygen to breathe (too much oxygen is also a problem!), if the atmosphere is explosive or contains toxic gases/vapours that threaten your health or life!

What should I be looking for?

The choice of monitoring equipment is expansive, but we must always keep in mind what it is that we are trying to achieve. We need to ask ourselves the following:

  1. Do I need ATEX certification and if so what zone classification do I need?

  2. How am I going to take a sample from my confined spaces’ atmosphere; do I need a pumped instrument so I can draw a sample from a distance without entering the confined space or a diffusive instrument that is easier to wear?

  3. What contaminants or toxic compounds are present; if so, what are the short or long term health implications and at what concentrations?

  4. Is there a potential risk of a flammable or explosive atmosphere?

  5. If flammable gas or vapour is present, do I need to calibrate for my specific flammable gas or vapour (Paragraph 94, Confined Spaces Regulations 1997) and can my gas monitor do that?

  6. Does my testing and calibration need to include daily operator checks for instrument response? What are the manufacturer’s recommendations on calibration and testing intervals, as I need to be in accordance with them (Paragraph 184, Confined Spaces Regulations 1997)?

So let’s look at these questions in a little more detail and attempt to cast some light!

1. ATEX Certification

ATEX certification is required if there is a risk of an explosive mixture of gases or dust present. What ATEX certification is required is often one of the least understood aspects of confined space entry monitors, by manufacturers, distributors and end users alike, all finding this requirement challenging. Its explanation is too long for this article, but it is essential that you get a monitor with the right certification. I would recommend taking the time to visit for a better understanding of ATEX classifications.

2. Pumped or Diffusive

This is a relatively easy one to decide on an answer. If I am at point A and I need to take a sample from point B, I need a pumped instrument. The Confined Space Entry Regulation 1997 require an atmosphere to be tested prior to entry and to do that you need a pump to draw the air sample from within the space out to