The Dangers of Confined Space Working Should Never Be Underestimated

Tue 31 Aug 2021
posted by Arco Professional Safety Services

Article Originally Released in November 2020


Brian Grunes, Arco Professional Safety Services Confined Space training expert offers guidance on the risks of confined space working and the training you need to help prevent confined space accidents in the workplace.

A significant number of people are killed or seriously injured working in confined spaces in the UK each year. These accidents happen across a wide range of industries, including manufacturing, utilities, maritime, construction, offshore and agriculture. This includes workers in the confined space itself and those who may have to try to rescue them when things go wrong. Despite legislation and health and safety measures, these statistics highlight that confined space working poses a very high risk and it’s important to ensure that the right people have the correct skills and capabilities for the roles they undertake. Training is just one part of ensuring the safety of working in confined spaces.

The existence of confined spaces in some workplace environments can be reasonably easy to identify and understand. Tanks, vessels, sewers among others are known to be confined spaces to people working in those industries; however, the existence of confined spaces in commercial or non–industrial premises are less well known. Service ducts, lofts and void spaces, plant rooms or poorly ventilated rooms can be confined spaces too and often found in commercial buildings, hospitals, universities and residential dwellings. Some confined spaces will also develop during construction, or when work activities such as welding or cleaning is being carried out. These spaces are just as hazardous as those found in industrial environments and demonstrate that systems of safe working must be in place in every environment.

However, it may not be straight forward as confined spaces are not necessarily enclosed on all sides. For example, silos, vats, trenches and ship holds are not fully enclosed and may have open tops or sides. Confined spaces may also differ in size, ranging from small and difficult to work in to large like service reservoirs and ships holds. Some confined spaces are also used regularly by people during their work, for example paint spraying booths for car repairs.

It’s important in the first instance to identify confined spaces so that the right controls can be put into place. The Approved Code of Practice (ACoP) L1010 Safe Working in Confined Spaces provides details on the relevant provisions that must be considered. You will need to show you have followed the code or complied with the law in some other way otherwise a court will find you at fault.


The ACoP has a flow chart that helps in the decision-making process by establishing if a space is confined. There are two key parts:

  • Is the space substantially or totally enclosed?
  • One or more of the specified risks must be present or foreseeable

defining confine space



Specified Risks:

  • 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


It’s worth noting that if a space is identified as confined, then the regulations apply in full even when the specified risks are controlled. If a space becomes confined due to the nature of the activity being undertaken, for example due to fumes generated when cleaning, then the space may cease to be a confined space when the activity ends, and the fumes have been removed by ventilation.


The ACoP provides an excellent framework to follow with three core principles:

  • Preventing the need for entry
  • Safe working in confined spaces
  • Emergency arrangements


Preventing the need for entry

In every situation you should not enter a confined space and should prevent employees and others from working in them where it is reasonably practicable to undertake the work without entering.



  • Testing the space from outside with long tools or probes
  • Cleaning from outside with jetting, steam or in place cleaning systems
  • Clearing blockages in silos where voids can form with remote operated flail devices
  • Using remote cameras (CCTV) to see what’s happening inside.


Safe Working in Confined Spaces

The types precaution will depend on the nature of the space and the results of the risk assessment. There are elements to consider, such as: supervision, competence for the confined space work, communications, testing and monitoring of the atmosphere, ventilation, Personal Protective Equipment, Respiratory Protective Equipment and much more. These may also form the basis of a ‘permit to work’.

Safe procedures consist of all the appropriate precautions being taken in the correct sequence and a safe system of work will only ever be as good as its implementation.


Emergency Arrangements

No one should enter or work in a confined space unless emergency arrangements are in place that are appropriate to the identified level of risk. This may range from something as simple as self-rescue, to having full rescue capability with the presence of a team ready to enter and extract a casualty.


Training solutions

Arco Professional Safety Services offers a joined-up approach to health and safety training with a tailored mix of consultancy, training, services and safety equipment. We work with customers to help manage, transfer and mitigate risks for confined space working.

Practical confined space training options range from Confined Space Awareness Training, through Low, Medium and High Risk modules, plus Rescue Training and sessions covering the selection and maintenance of equipment involved in safe confined space working, such as gas monitors, breathing apparatus and personal protective equipment.

The confined space courses we offer are mapped against a range of National Occupational Standards (NOS) used by a range of Awarding Organisations (AOs) to produce assessment criteria for the level of qualification required. The main AO that we use for a range of awards is City & Guilds. We can also design and deliver a bespoke solution which works for your business.

The courses that we provide with regards to accreditation are mapped against the same standards to both ensure the quality and credibility of the product. This also ensures that if a situation develops which challenges the training, we can evidence against a range of learning outcomes that map back to the NOS.


Training on or off-site

Training can be delivered on or off-site, at one of the company’s specialist training facilities around the UK or, on site through Arco Professional Safety Services award-winning mobile Confined Space Training Units. Arco Professional Safety Services has four specialist Safety Centres located at Enfield (South), Stafford (Midlands), Warrington (North West) and the newly-opened Linlithgow (Scotland). These centres offer both indoor and outdoor purpose-built facilities that have been specially designed to simulate real life hazards in a controlled environment. 

Using the Confined Space mobile training units, trainees are immersed in a highly realistic learning experience which offers different industrial confined space scenarios in a safe environment. Real-time videoing also allows for continual monitoring of activity, live instruction from the trainer and observed learning outside the tunnels system. Supporting services such as face-fit testing can be offered and accredited to Fit2Fit.



Continuing to provide practical skills is essential in critical and high-risk industries and so Arco Professional Safety Services has adapted operations at its training centres to provide attendees with a safe learning environment and the reassurance they need to join critical training programmes. This includes new precautions, such as pre-start COVID questionnaires, non-contact body temperature checks, staggered break times to minimise unnecessary people movement and mixing and the use of larger rooms equipped with enclosure screens to ensure adequate social distancing. Arco Professional Safety Services has also launched a number of video conference options including a Confined Space Working Awareness, half day course.


Other services

Arco Professional Safety Services also offers confined space inspection services such as detailed structural examinations in hazardous environments, remote controlled surveying of underground assets such as drainage and pipe systems and topographical surveys and mapping.

Arco Professional Safety Services also provides 24/7 dedicated standby rescue teams and specialist confined space rescue consultants who are highly experienced in confined spaces safety and provide both 'entry' and 'non-entry' rescue solutions to businesses.

For more information on Arco’s Professional Safety Services Confined Spaces services, please visit