Confined spaces

A “confined space” can be either be:

  •  a place which is substantially, though not always entirely, enclosed or
  •  a place where there is a reasonably foreseeable risk of serious injury from hazardous substances or conditions within the space or nearby.

Some confined spaces are easy to identify, such as closed tanks, vessels, silos, ducts, pipes, chambers, sewers and drains etc.  Others are less obvious, such as deep excavations, pits, flues, manholes and access chambers, slurry stores, wells, building voids, vats, open-topped tanks etc  Basement rooms with limited access and an inadequate air exchange can sometimes become a confined space.  A confined space may not necessarily be enclosed on all sides and may only become a confined space due to a change in the conditions inside.

The main foreseeable risks within a confined space are:

  • the space may contain potentially hazardous substances and/or atmospheres
  • the space may contain an oxygen deficient atmosphere due to the build-up of asphyxiants
  • the risk of fire or explosion
  • conditions which could lead to engulfment or entrapment by a free flowing solid
  • the risk of drowning
  • the risk from an increase in body temperature due to the conditions within the space.

In some circumstances the simple act of breathing may be enough to create a life threatening situation.

The Confined Spaces Regulations 1997 apply to work within such areas and are concerned with prevention of risks such as asphyxiation, drowning, injury through fire or explosion or loss of consciousness due to excess heat or the presence of hazardous fumes.  The Regulations are not concerned with spaces that are simply small, or enclosed but do not have these types of risk associated with them. 

The Regulations prohibit work in any confined space if entry isn’t necessary.  Where there is no alternative and entry is needed, work may only be carried out in accordance with a safe system of work and with suitable emergency procedures in place. 

Within the University, no person is permitted to enter ANY confined space of a type where a risk of the kind indicated above may exist without first carrying out a suitable and sufficient risk assessment and the establishment of a safe system of work.  In many cases this will require development of a “Permit to Work” system, staff training and provision of specialised air monitoring ventilation and rescue equipment.  Confined spaces may contain an atmosphere that cannot support life and uncontrolled entry, without such precautions does carry a genuine risk to life.  Heads of Management Units should ensure that any areas where their staff may encounter such risks are identified and entry to them either prevented or managed appropriately.  SEPS have produced a detailed Guidance Note which can be found here:- 
Working safely in confined spaces 

Furthur useful information on confined spaces is also available from the HSE Confined Spaces website which can be found at