Confined Spaces and Gas Detection

Understanding consequences and managing risks

by Matt Powell-Howard, NEBOSH


NEBOSH Qualifications Development Manager, Matt Powell-Howard, explores confined spaces, the need for adequate gas detection measures, and talks to two highly experienced health and safety professionals about how to manage and control the risks.

Before looking more closely at the relevant health and safety control measures, it is important to understand what a confined space is and just how severe the consequences of failing to manage the relevant risks can be.

In the UK, a confined space is clearly defined by the Health and Safety Executive’s Confined Spaces Regulations (1997). Under the regulations a confined space “must be a space which is substantially (though not always entirely) enclosed” and “one or more ‘specified risks’ must be present or reasonably foreseeable.”

The risks specified in the regulations are:

  • Serious injury due to fire or explosion
  • Loss of consciousness arising from increased body temperature
  • Loss of consciousness or asphyxiation arising from gas, fume, vapour, or lack of oxygen
  • Drowning from an increase in the level of a liquid
  • Asphyxiation arising from a free-flowing solid or being unable to reach a respirable environment due to being trapped by such a free-flowing solid

The regulations go on to say that while some confined spaces are fairly easy to identify, such as sewers and chemical tanks, this is not always the case; a confined space may not always be enclosed on all sides, for example vats and silos. Confined does not necessarily mean small either. Ship’s holds are very large, but they could still fall within the definition. Likewise, confined space does not mean it must be difficult to get in or out of, as large openings could still be present. Finally, a confined space does not have to be a place where work is not always carried out. Spray painting booths in car repair centres are used daily by people in the course of their work, but would still be classified as a confined space.

Severe consequences

An incident that occurred in the United States last year, illustrated not only the severe consequences of failing to manage the risks of confined spaces, but also highlighted the need for clear procedures and the mandatory use of protective equipment.

Three people working for a utility company in Florida were killed in January 2017 after they succumbed to toxic gases inside a manhole. Elway Gray, a 34-year-old pipe layer, entered the confined space and quickly became unresponsive. Louis O’Keefe, a 49-year-old labourer then entered the manhole in an attempt to rescue his colleague. A third worker, Robert Wilson, a 24-year old equipment operator also then followed in to help. All three died. Post-incident atmospheric testing revealed lethal levels of hydrogen sulphide and carbon monoxide had been present.

“while some confined spaces are fairly easy to identify, such as sewers and chemical tanks, this is not always the case; a confined space may not always be enclosed on all sides”

US Occupational Safety and Health Administration (OSHA) investigators uncovered a failure to purge or ventilate the confined space before entry. Further, there was a failure to provide necessary rescue and emergency equipment for employees that were overcome inside a permit required confined space. They also found a severe lack of written planning and communication, no use of a calibrated direct-reading device to test for toxic gases and a failure to provide relevant training for working in confined spaces.

While the circumstances, location and industry involved are different, this US case is similar in terms of outcome to an incident that occurred in Scotland in 2009. There, two men lost their lives on a fish farm barge in Argyll. Maarten Pieter Den Heijer, 30, and 45-year-old Robert MacDonald lost consciousness in a low oxygen environment below deck while trying to help a colleague who had passed out.

Inspectors from the HSE found their employer had failed to:

  • Suitably prepare the men for working in the small, sealed chambers on the barge
  • Provide a safe way for them to work
  • Deliver information and training

Further, a risk assessment would have shown that the air in the chamber should have been tested and monitored for oxygen levels, but that the confined space risk had not been identified.

Both cases are typical examples of fatal incidents which happen throughout the world every year concerning confined spaces. Many involve workers attempting to rescue their colleagues and a significant proportion involve toxic gas or oxygen deficiency. However, there are other risks, as outlined earlier, including fire and explosion arising from dangerous atmospheres.

Safe systems of work

It may seem obvious, but a key consideration to think about is whether the work has to be completed from inside the confined space. It is always preferable to explore ways that would eliminate the need for confined space working.

That said, it is often unavoidable and this is where you must develop and implement systems that keep everyone safe. If we refer, once again, to HSE guidance some of the essential things you need to consider include:

  • Appointment of a supervisor
  • Are people suitable – experienced and trained – sufficiently for the work?
  • Isolation of gases, liquids and other free flowing substance
  • Thorough cleaning of confined space prior to entry
  • Size of the entrance/exit
  • Provision of ventilation
  • Testing for airborne contaminants
  • Special tools and lighting
  • How to raise the alarm
  • Do you require a permit to work?
  • Emergency arrangements: Communications tools and procedures, Rescue and resuscitation equipment, First-aid procedures, Rescuer capabilities, Emergency services, Shut down

This list is not exhaustive but provides a starting point for developing a safe system of work.

It’s important to remember that each confined space can be unique and present its own set of hazards and risks, and as such, each should be appropriately risk assessed before work commences.

To understand how the risks can be best managed, I spoke to two highly experienced and qualified health and safety professionals, Robert Williams of Wales and West Utilities in the UK and Jacques Krog of Refraline in South Africa.

“it is always preferable to explore ways that would eliminate the need for confined space working”

Control measures

Robert Williams is Health, Safety & Environmental Manager (Operations) at Wales & West Utilities in the UK. The company employs around 1,300 skilled people and supplies gas to approximately 7.5 million homes and businesses throughout Wales and the south west of England. Robert’s background is in construction, having previously worked as a civil engineer. He has several NEBOSH qualifications, including the new NEBOSH HSE Certificate in Process Safety Management.

For Robert, the key to managing confined spaces risks is a strict permitry regime and regular formal and informal training. “As a gas distribution network, we carry out a lot of excavation work to identify where any leaks are coming from and repair them. Our people are fully trained and competent in gas detection and everyone is issued with personal gas monitors and advanced atmosphere testing equipment. As well as that they have breathing apparatus and are fully trained in the use of all equipment and how to operate in a gaseous environment and confined space environment. Our teams will also work on the bigger, higher pressure regimes. Here they encounter more of your traditional confined space and again the SCO (Safe Control of Operations) permitry, procedures and guidance are all in place and regular training is provided.”

Because of the emergency nature of some gas leaks, speed can be of the essence out in the field. However, training focuses on the need to carefully assess the risks and then act accordingly, whether it involves bringing in other members of the team or seeking guidance from supervisors. Fine-tuning the procedures is an ongoing process: “One of the things we’ve identified is that there can be a danger in the operatives simply trying their best to get the job done. If there is something in our safety procedures that is perceived as a ‘blocker’ and which makes it too onerous for them to work, then we have to review it. You have to make it workable as well as safe, but with the training we provide and the constant reminder of the risks the operatives understand that safety in confined spaces is paramount.

There is always a risk that someone might not put on their BA (breathing apparatus) equipment, for example, because they think the job will only take two seconds and they can simply hold their breath. However, through our repeat training programme, reminding the team of what can go wrong, they all understand that it is not worth taking chances. And on all of our inspections, number one on the checklist is making sure safety critical equipment like the BA equipment is easily accessible, ready to use and is being used correctly.”

Risk assessment and planning

Jacques Krog is Group Safety, Health, Environmental and Quality (SHEQ) Manager at Refraline, a company that has its headquarters in South Africa, but which also operates in various countries in Africa, Malaysia and South America. Jacques holds the NEBOSH International Diploma in Occupational Health and Safety and has over 20 years of experience working in health and safety.

Refraline specialises in the design, installation, repair and maintenance of refractory and corrosion solutions for a wide range of industries including ferrous and non-ferrous metals, chemical, petrochemical, power generation and mining. “Refractory engineering involves rebuilds to boilers and furnaces and things like that, so we carry out a lot of confined space work, including breaking these structures down from the inside,” explained Jaques.

“One of the less obvious risks we face is noise. Breaking out bricks within a small space means the noise tends to accumulate. Heat stress is another, as these spaces can become very hot and some may not have fully cooled down before the work is due to begin. However, perhaps the biggest threat to our workers is accumulation of gases such as carbon monoxide and dust, including crystalline silica. Every confined space situation presents different risks, so we tend to work with subject matter experts who will understand the kind of gases likely to be present and where they might accumulate within the space. Then there will be a period of rigorous testing to decide what steps are needed to keep our workers safe.”

Jacques added: “Planning these operations is critical. How you do it, where you do it and what time you do it, all of these things play a part. Who is going to work in the vessel is also a key question, because people need to be declared physically and psychologically fit to work in confined spaces. And of course it is really important that every single person that enters the confined space is fully trained, including in what to do in an emergency and how to use their equipment properly.

“every confined space situation presents different risks, experts understand the kind of gases likely to be present and where they might accumulate within the space”

PPE and supervision

When it comes to Personal Protective Equipment (PPE), Jacques told me this can be very specific for confined space use. “It’s not necessarily the same as standard PPE; there can be specialist respiratory equipment, gas testing equipment and even timers. Some of the spaces where we work in the petrochemical industry have certain catalysts inside, meaning you cannot work for longer than 30 minutes – no matter what you wear. You need to time that the person works for exactly 30 minutes before they have to come out and the next group has to go in for 30 minutes. Size can also matter as some of the spaces are so small that the average person cannot enter.

“When it comes to gas detection equipment I have learned that cheaper is not always better. You need to think about simple things like maintenance; can it be repaired? Can it be calibrated? Is it robust enough for the environment? How accurate is it? I was once in a confined space myself when an alarm went off on the monitor. I started to panic a little, but when I looked it was a battery prompt! This equipment is a lifeline and you have to understand it and test it regularly, as well as the maintenance of parts such as batteries.

“It’s worth noting that with some confined spaces you simply cannot go in at all. In these instances we’ve used unmanned remote machines, connected via a pendant station to break down the structure from the inside to fully eliminate any risk.”

Jacques added: “Supervision is also important. We have what we call ‘watchers’ who monitor the people inside and as soon as they become aware of something going wrong, they will literally pull them out by their lifeline. Watchers are always competent supervisors who know how to do the work and know the hazards and dangers associated with confined spaces. That’s critical and they are always a vital part of the continuous monitoring that is undertaken during a confined space entry.”

Culture is key

Jacques concluded by providing two further interesting pieces of advice. The first is to practice. On some of Refraline’s larger projects the team will carry out practice runs to make sure everything runs smoothly. This is combined with confined space training, which must be completed by members of the team every year. The second is to be aware that “people working in confined spaces can get used to it.”

“For me this is never a good thing, said Jacques. “Because once you get used to something, you tend to take shortcuts. That’s how humans are. So, as well as a lot of supervision, there also needs to be continuous inspections and audits. It’s about getting the culture right. If our workers are following the correct procedures, the correct systems and permit conditions, using the right PPE and are well prepared, then we can keep them safe.”

Author Details

Matt Powell-Howard, NEBOSH

Matt Powell-Howard graduated in Safety and Environmental Management from the University of Hull and holds a Master of Arts degree in Education from the University of York. He worked initially in the chemical process industry in the UK for a number of top tier COMAH sites before moving on to SHE roles in consultancy, manufacturing, construction, quarrying and the hydrocarbon industries.

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