So, what is a confined space? Many people, due to the word ‘confined’, assume it must mean a small space – and it can be, but not always.
‘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 (Confined Spaces Regulations 1997).
Identifying the risks
The following questions can help you to decide whether an area is a confined space, in accordance with UK legislation. They are extracted from ‘Approved Code of Practice and guidance’ for Safe Work in confined spaces, based on the Confined Spaces Regulations 1997:
Is the space substantially or totally enclosed – if the answer is ‘no’ then the space is not classified as a confined space, but if the answer is ‘yes’, then you need to consider if there is a specific risk of one or more of the following:
- Serious injury caused by fire and 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 solid
- 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
If the answer is ‘yes’ to any of the above questions, then the space is a confined space and subject to the Regulations.
It’s important to also consider if the work to be done in the space will introduce one or more of those risks. If so, this space is also a confined space and subject to the Regulations, as long as the work being carried out and any residual risk remains, e.g. until produced fumes have been fully vented.

If you answer ‘no’ to the above question, then the space is not a confined space, and not subject to the Regulations.
There are many examples of confined spaces, but what you need to focus on is the type of activities carried out by your own organisation and how the above specified risks can be encountered within your specific environments.
Preventing entry
The first question that you should consider is ‘is it necessary to enter the confined space or can the task be done in another way’, therefore preventing entry. If, for instance a tank needs to be cleaned inside, having previously contained a solvent, then it might be possible to ventilate the tank and then clean it using long handled tools, therefore preventing entry.
Preventing entry may require a more complex and expensive engineering solution. Things to consider maybe, how often the task needs to be done, and the type of harm that can occur. Ultimately, you are looking to prevent illness, injury and death. It should also be noted that entry to confined spaces can be expensive, requiring additional resources in terms of people, equipment and time. So, you need to weigh all this up and make a decision.
“if entry cannot be avoided, a suitable risk assessment must be carried out”
If the decision is that entry into a confined space cannot be avoided, then a detailed, suitable and sufficient risk assessment must be carried out and preferably backed up with a permit to work.
We also need to bear in mind that the Health and Safety at Work etc. Act 1974 requires employers to provide employees with a safe system of work, and for employees to abide by that safe system of work.
Safe Systems of Work
In order to achieve a safe system of work, you will need to generate a risk assessment, method statement based on your work procedures and ideally issue a permit to work on the commencement of the task, indicating the time scale of the task, named competent person in charge of the work equipment to be used, supervision required, means of rescue etc. Needless to say, the work must be planned in advance, and many checks carried out in order for the task to be carried out safely. Sometimes entry to confined spaces can be categorised as low risk, but the work still needs to be planned and a safe system of work generated.

Other entries into confined spaces will be deemed to be medium or high risk and controls must be appropriate, in order to mitigate the risk level to remain as low as is acceptable to all involved, but in particular, the operative(s) carrying out the work.
It is preferable to include a number of people in the planning and risk assessment process. The people or person carrying out the work should be included in the process, as should the health and safety practitioner, a safety representative and the manager requiring the work to be carried out. The number of people involved may vary, depending on the size of the organisation and the complexity of the task.
Things to consider at the planning stage can include the time scales of the work and the levels of competence required.
Do people have those levels of competence, or does training have to be organised and qualifications achieved?
Anyone entering a confined space, must be trained and competent with an in-date proof of qualification.
Is any preparatory work required before entry can take place? What needs to be done and when will it be finished?
Preparatory work could include for instance, a necessary period of ventilation prior to entry, or perhap, isolation of services such as electricity, gas or water.
Are all tools and equipment available, or is there any requirement for inspection, calibration or replacement of equipment, or purchase of new equipment?
All of these things take time to organise, and time needs to be allocated.
Other considerations include:
- Is the entry weather dependent?
- Have appropriate health checks been carried out? – Anyone entering a confined space needs to be fit and healthy.
- What is the rescue plan, and what resources will be required to implement the plan?
- What rescue equipment is required, is it available, inspected, fit for purpose and in situ prior to entry?
With your planning in place, you can start to build your risk assessment, but bear in mind that it may need adjustments on the day of the work taking place as things like the weather may need to be considered.
“preparatory work could include a period of ventilation prior to entry, or isolation of electricity, gas or water”

Conducting a Risk Assessment
To conduct a suitable and sufficient risk assessment, you first of all need to identify the hazards that may be encountered. The dictionary definition of a hazard is ‘something with the potential to cause harm’, and risk is ‘the likelihood of harm occurring, and the level of harm that may be caused’. What you are aiming to achieve, is being left with the lowest level of residual risk that you are happy to accept. There is never a zero level of risk, because we are human, and as such are not totally predictable in our behaviour, so we need to take into account the human factor of human error.
You may wish to involve the same set of people to conduct your risk assessment and method statement that you used at the planning stage, and definitely include the person or people who will be carrying out the task.
Don’t forget to factor in things such as means of communication – mobile phones may not work, and if they do, they could generate a spark and cause a fire or explosion.
You need to identify the hazards of the task, identify who can be harmed and how, and consider any control measures that are already in place. At this stage you should estimate the level of risk in terms of the likelihood of harm occurring and the level of harm that could happen. You may not have adequate control measures in place at this stage, so your risk rating may be quite high or even very high.
You will then need to consider further controls in order to mitigate the risk to an acceptable level. If your overall risk rating is still high, then you need to consider and implement further control measures.
Understanding Regulations
To achieve a Safe System of Work for entry into a confined space you may also have to consider other Regulations, such as:
Manual Handling Regulations
E.g. how are you going to get tools and equipment in and out of the confined space; do you need any mechanical aids?
Lifting Operations and Lifting Equipment Regulations
E.g. winch and harness for access, egress and rescue. Any equipment used for lifting people must be independently inspected every six months, and visually inspected before use. Failure of such equipment could cause serious injury or death. People must also be trained specifically in their use, be deemed competent to do so, and provide evidence of competence. Harnesses have a specific ‘shelf life’, and will need to be disposed of and replaced after a given time.

Provision and Use of Work Equipment Regulations
E.g. any tools to be used, must be fit for purpose and in good condition. If you need personal gas monitors, or other gas monitoring equipment, they must be calibrated and in date prior to use. Do you need to have intrinsically safe tools or equipment to prevent any sparks that could cause fire and or explosion.
Depending upon the hazards that are likely to be present, you will probably require some sort of specialised equipment to mitigate the hazards. You need to be aware that there a vast range of tools and equipment on the market, and that you need to select the most appropriate for the work. You also need to be aware that there also a wide range of prices, so how do you select the right equipment at the right price.
“personal gas monitors must be calibrated and in date prior to use”
You may have expertise within your organisation, such as experienced operatives who have preferences for particular pieces of equipment and who have carried out such tasks previously, and perhaps regularly. You may have tools and equipment already in place, but you need to bear in mind that these will not last for ever and will need to be replaced at some point.
It is accepted that most organisations do not have a bottomless pit of money to spend on tools and equipment, and if you are looking to invest initially, it can be a difficult task to obtain value for money, taking into account all of the safety aspects. If you are struggling with this aspect, there are some steps you can take to assist with your decision making:
- Look at advertisements in specialist safety magazines, such as this one –this will give you a broad view of what is available
- Attend health and safety events, where reputable companies will readily give you information, help and advice, and of course, try to convince you that their products are the best!
- Invite various suppliers to your organisation who can demonstrate equipment to competent operatives, who will be required to use the equipment. Encourage them to ask questions and gain satisfactory answers from the potential supplier
- If you have good relationships with other organisations who do similar tasks, ask them for help and advice
- Consider maintenance regimes and repair services; look at their terms and conditions
- Do not make rushed decisions because you are under pressure to get the job done

Personal Protective Equipment Regulations
You may need some specific and possibly complex equipment that people have to wear that will cause discomfort and stress. You will need to take this into account. It may be that an individual can only work within the confined space for a very limited time to prevent them overheating and lapsing into unconsciousness, so you may need more than one individual to carry out the task.
Control of Substances Hazardous to Health (COSHH) Regulations
Are any hazardous substances being used or removed – you will need to know the properties of the substance and all the precautions to be taken.
“more people are killed trying to rescue others trapped in confined spaces”
Working at Height Regulations
Do you need a scaffold tower, mobile elevated work platform, cherry picker to gain access; if you don’t have your own, this equipment can be hired in, together with a qualified operative, then you just need to check the paperwork and that the operative has a current qualification.

Management of Health and Safety at Work Regulations
These are the regulations that require all employers to risk assess their work activities, and if you are an organisation with five employees or more, you must write down your risk assessments and tell people affected what they mean, so that they can follow them and work safely. Finally, a few words of warning – do not allow a lone worker to work in a confined space. Remember that more people are killed trying to rescue people who have become trapped in a confined space if that space has, for instance, become oxygen deficient and rendered someone into unconsciousness, then the next person to enter will suffer the same fate.