Can you work alone in a confined space? Generally speaking, no. Confined space work can involve serious hazards that make lone working unsafe, and HSE guidelines specifically mention confined space operations as an example of the kind of high-risk work that tends to require the presence of at least one other person.

Confined spaces can expose workers to hazards such as fire, flooding and harmful gases. Because of this, workers should refrain from entering confined spaces at all where possible – and if confined space work is unavoidable, a thorough risk assessment must be carried out beforehand.

Any enclosed (or largely enclosed) place where there is a reasonably foreseeable risk of fire, explosion, loss of consciousness, asphyxiation or drowning counts as a 'confined space' for health and safety purposes. Note that a space doesn't necessarily have to be small, difficult to enter or completely enclosed to count as 'confined'.

The Health and Safety Executive (HSE) uses the above definition when explaining which workplaces are covered by confined space safety rules.