Confined spaces are perhaps the most misunderstood hazards in the UK safety world. While I have been a health and safety practitioner since the 1990s, I have regularly observed this. In this article I write about the history of confined spaces in the UK, with reference to the law and significant events, what are confined spaces, and what are the common misperceptions that are held about them.
From my experience I have observed over many years that health-related hazards are more difficult to comprehend to a workforce rather than traditional safety hazards. Workers understand that moving machinery and workplace transport can cause significant injury – they can see it and hear it and therefore their understanding of it is a simpler process. Confined spaces have prescribed hazards which are defined within the Confined Space Regulations 19971. Hazards such as high or low oxygen levels, however, cannot be seen, have no smell, and therefore cannot be properly considered as a hazard in some workers minds. From my experience this extends to managers and supervisors who assess hazards, and indeed send their workforce to work within environments such as these.
“hazards such as high or low oxygen levels, cannot be seen, and have no smell”
What is a Confined Space?
This very question seems to confuse workers and health and safety practitioners. To best assess what is a confined space, we need look no further that the regulations and the helpful Approved Code of Practice L1012. For a space to be defined as confined it must meet the following criteria:
(2) “confined space” means any place, including any chamber, tank, vat, silo, pit, trench, pipe, sewer, flue, well or other similar space in which, by virtue of its enclosed nature, there arises a reasonably foreseeable specified risk; “specified risk” means a risk of-
(a) serious injury to any person at work arising from a fire or explosion;
(b) without prejudice to paragraph (a)-
(i) the loss of consciousness of any person at work arising from an increase in
(ii) the loss of consciousness or asphyxiation of any person at work arising from gas, fume, vapour, or the lack of oxygen;
(c) the drowning of any person at work arising from an increase in the level of a liquid; or
(d) the asphyxiation of any person at work arising from a free flowing solid or the inability to reach a respirable environment due to entrapment by a free flowing solid.” (Confined Space Regulations 1997, Regulation 2).
In summary, for a space to be a confined space within the meaning of the regulations, it must meet the definition of confined and there must be one of the significant risks detailed at (2)(a) to (d).
Confined Space Misapplication
I have found that the definition of confined spaces is often misunderstood, misinterpreted, and misapplied in industry. I worked for much of my work life in the power industry. Starting at one station, in my first few weeks, whilst getting to grips with the site, I was taken on a tour. After seeing the boiler (confined space – ‘tick’), the gas turbine (confined space – ‘tick’), the steam turbine (confined space – ‘tick’) I climbed to the turbine hall roof with my colleague and guide. At the top ladder, prior to stepping on to the roof I noticed a confined space warning sign. I queried this and was told that the roof had been classified as a confined space because it had restricted access and was high risk.
I discussed this with my colleague, and it appeared that the health and safety department had classified the roof as a confined space. I discussed the requirements for a space to be confined as defined with my colleague, and we chatted about the regulatory requirements for the definition to apply. It appeared that the misunderstanding had arisen by a simple misapplication of the regulations. The roof was restricted – it required a ladder to access it, and this was rightly controlled by permits, roof ladder locks etc. – but it was not a confined space. It was clear that none of the hazards in (a) to (d) were present or foreseeable. There was certainly a significant hazard from work at height, but this is not one of the defined hazards from the regulations. However, whilst not being part of the confined spaces definition, work at height and other hazards should always be considered as part of a risk assessment within a confined space.
Similarly, at the same power station, a cable pit was marked as a confined space. It had four walls, ladder access and was therefore restricted. However, it had none of the hazards detailed at (a) to (d). In this case, the application of ‘confined space’ had been allocated based on OSHA requirements and definitions3. OSHA is the US regulator, carrying out a similar function to the UK’s HSE. OSHA categorise their spaces as confined spaces in two categories – non permit entry and confined spaces requiring permit entry. The cable pit met the OSHA definition of a non-permitted confined space.
“the definition of confined spaces is often misunderstood, misinterpreted, and misapplied in industry”
Other Industry Examples
In the paper industry, paper pulpers are used to mix the large paper bales with water and sometimes bleaches and other chemicals. They are similar to a very large food mixer, with a rotor at the bottom. Pulpers are fed paper product by conveyers, have a large water tank above them, which releases large volumes of water on demand, to mix with the paper pulp. Paper pulpers are clearly confined spaces as defined. They are entered by ladder or platform from above, have sloping sides and fill rapidly with water. They therefore have a largely/fully enclosed structure, and they have a foreseeable risk of drowning. Many pulpers are often open topped, and this sometimes causes risk assessors and workers due to enter them to mentally ‘downgrade’ them as confined spaces. However, the risk of drowning does not require that there be a top to the pulper – the rapid filling of water from a water tank would quickly cause drowning, aided by the confined nature of the pulpers walls. HSE state “A confined space is one which is both enclosed, or largely enclosed”4.
I have often observed confined space teams gas testing pre-entry to paper pulpers. This appears to be another misperception in confined space risk assessment. Paper pulpers have product changes every hour or less. Once the pulp and water have been suitably mixed, and the consistency is as desired, the pulp mixture is pumped to a storage tank and the pulping process begins again. There can never be gas arising from empty, regularly emptied pulpers – the risk is from drowning, not from gas. I have observed this practice in other industries – assessment teams appear to believe that because something is classified as a confined space there must be a hazard from gas. This is not the case – any of the hazards from (a) to (d) can apply in isolation or there may be a combination of hazards.
“Ryan Preece was killed along with Robert Simpson as they entered an underground chamber”
The History of Confined Spaces
Earlier in this article, the definition from the Confined Spaces Regulations was quoted. This was, however, not a new definition, but taken from the Factories Act 19615. A confined spaces incident in 1996, in Crymlyn Burrows, near Swansea, was the catalyst for the 1997 regulations to be written.
“Ryan Preece was 27 when he was killed along with colleague Robert Simpson as they entered an underground chamber at a sewage pumping station near Swansea and were overcome by toxic fumes on October 10, 1996”6.
The two sewerage workers were experienced workers employed by the local authority. They had entered the sewage network, as they often did as part of their role. Unbeknown to them, an adjacent chemical factory had suffered a ‘loss’ of 3 tonnes of a refrigerant chemical which had leaked into the sewer. Refrigerant gas is heavier than air and the level of oxygen was displaced to the point where the atmosphere was not sufficient to sustain life.
For many of us, who are used to confined spaces, the thought of entering a sewer system with no apparent controls is unthinkable, and this incident perhaps demonstrates how far confined space controls and awareness have come following this incident. However, whilst a sewer is clearly a confined space, we must always be cognisant of the words of HSE in their short guidance document ‘Confined spaces: A brief guide to working safely; INDG 2587’, which states:
“It is not possible to provide a comprehensive list of confined spaces. Some places may become confined spaces when work is carried out, or during their construction, fabrication or subsequent modification.”
How do we Decide if Something is a Confined Space?
To do this, we must always go back to the regulations and their definitions. To be a confined space, the space must be enclosed or largely enclosed and one/a combination of the significant hazards at (a) to (d) must be present. We must always be aware of creating a temporary confined space from the work that we are undertaking.
Principles of Prevention or the Hierarchy of Control
The Management of Health and Safety at Work Regulations 19998, at Schedule 19, provide a hierarchy of control which should be applied when risk assessing. The first control in the General Principles of Prevention is “avoiding risks,” which readers may recognise as ‘eliminate’ (the hazard) from NEBOSH studies they may have undertaken. L101 guidance document states:
“[para] 48 If it is not reasonably practicable to avoid the need to work in a confined space the duty holder must assess the risks connected with entering or working in the space. The assessment should identify the risks to those entering or working there, and any others, for example, other workers including contractors and the general public in the vicinity who could be affected by the work to be undertaken. The risk assessment must be carried out by someone competent to do so.”
“concentrations of H2S over 1000 ppm cause immediate collapse with loss of breathing”
I often witness confined space control being applied at the ‘enter the space’ stage, and I rarely see evidence of discussions of avoidance. Below I have detailed some techniques which I have used to avoid, or control entry:
- The use of long handled tools – this is a simple, but often overlooked control which can effectively prevent the need to enter a confined space, or minimise it.
- The use of technology. Endoscopes can provide high resolution images, which may provide sufficient detail for engineers to avoid the need to enter a confined space. I have similarly used an underwater robot in a fire water sprinkler tank. This was not strictly a confined space but did minimise the time a diving team had to enter the water tank. Diving operations are not considered confined spaces and are not covered by the Confined Space Regulations 1997 (stated in Regulation 2), but rather the ‘Diving at Work Regulations 1997’10.
- The use of process equipment which automates work processes and removes the need for entry. Often these can be used in farming grain silos, and tanks containing liquids or sludges to name a few. Some examples I have seen involve flails which move the grain and prevent blockage, and piped systems which can spray high pressure water to maintain tanks’ cleanliness.
- Using gas detection equipment which allows the meter to be inserted remotely. I have seen many confined space teams sending someone in with the gas tester, not realising that this person may be exposed to an atmosphere which cannot sustain life. The very act of assessing the environment, may expose that assessor to unacceptable risk. This is particularly true of exposure to hydrogen sulphide (H2S) which at high concentrations would not provide enough time for escape once detected. There are many ways which this can be done remotely – I recommend discussion with gas detection device companies to explore options to avoid entry. A solution can simply be a plastic tube, which can be attached to the gas meter and inserted remotely.
The HSE indicate the following H2S concentrations in parts per million with the associated effects on the human body11:
- 0.0047 ppm is the recognition threshold of human smell, the concentration at which 50% of humans can detect the characteristic odour of hydrogen sulphide.
- 10-20 ppm is the borderline concentration for eye irritation.
- 50-100 ppm leads to eye damage.
- At 150-250 ppm the olfactory nerve is paralysed after a few inhalations, and the sense of smell disappears, often together with awareness of danger.
- 320-530 ppm leads to pulmonary edema with the possibility of death.
- 530-1000 ppm causes strong stimulation of the central nervous system and rapid breathing, leading to loss of breathing.
- Concentrations over 1000 ppm cause immediate collapse with loss of breathing, even after inhalation of a single breath.
This article has discussed how people frequently misunderstand confined spaces. To highlight this, one story which I was personally involved in underlines this. I approached the boiler in a power station, after hearing that a gas detection alarm had sounded over my radio. The confined space ‘top man’ had rightly emptied the boiler of personnel. The person whose alarm had sounded was feeling unwell and a first aider was called. Prior to any investigation of the space or gas levels, the Chief Engineer, accompanied by a number of engineering graduates started to enter the boiler. He was stopped by the top man and me, and his view was that the person whose alarm had sounded was unwell, and that was not really an issue for his team. After a long discussion of confined space hazards, the engineer had a moment of ‘dawning realisation’ when the risks of him entering the boiler (and those to his young team) were processed in his mind. He later said to me that he simply did not see the risk and thought that the risks were confined to the worker whose alarm had sounded. This moment was used to our advantage, and the subsequent safety flash was shared with the business. The engineer co-wrote it and presented it to the workforce, and his delivery was powerful and impactful. Our premise was that if a highly experienced engineer didn’t fully comprehend the risks of confined space entry, then we were all potentially susceptible to such a lack of hazard perception.
Confined space fatal injury is thankfully relatively low in the UK, and we have seen improved controls over the years. It appears, however, that in the US, confined space incidents are still causing high rates of fatal injury, and indeed a trend that is rising. The concerning, and rising fatality rate in the US indicates that the UK cannot rest on its laurels, regarding confined space entries. We must remain vigilant to the silent killer that is the confined space.