Confined Spaces Can Be Deadly
average, work in confined spaces kills 15 people every year in the UK
across a wide range of industries, from those involving complex plant
through to simple storage vessels. In addition, a number of
people are seriously injured. Those killed include not only people
working in confined spaces but those who try to rescue them without
proper training and equipment.
What is a Confined Space?
can be any space of an enclosed nature where there is a risk of death
or serious injury from hazardous substances or dangerous conditions
(for instance, a lack of oxygen).
Some confined spaces are fairly easy to identify, e.g. enclosures with limited openings:
• Storage tanks.
• Reaction vessels.
• Enclosed drains.
Others may be less obvious, but can be equally dangerous. For example:
• Open-topped chambers.
• Combustion chambers in furnaces, etc.
• Unventilated or poorly ventilated rooms or sheds
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.
What are the Dangers of Confined Spaces?
Dangers can arise in confined spaces because of a lack of oxygen. This can occur:
• where there is a reaction between some soils and the oxygen in the atmosphere.
• following the action of groundwater on chalk and
limestone which can produce carbon dioxide and displace normal air.
• inside steel tanks and vessels when rust forms
• poisonous gas, fumes or vapour
• Build-up in sewers and manholes and in pits connected to the system.
• Enter tanks or vessels from connecting pipes.
• Leak into trenches and pits in contaminated land, such as old refuse tips and old gas works
• Liquids and solids which can suddenly fill the space, or
release gases into it, when disturbed. Free flowing solids such as
grain can also partially solidify or 'bridge' in silos causing
blockages which can collapse unexpectedly.
• Fire and explosions (e.g. from flammable vapours, excess oxygen, etc.).
• Residues left in tanks, vessels, etc., or remaining on
internal surfaces which can give off gas, fume or vapour.
• Dust may be present in high concentrations, e.g. in flour silos.
• Hot conditions leading to a dangerous increase in body temperature.
of the above conditions may already be present in the confined space.
However, some may arise through the work being carried out, or because
of ineffective isolation of plant nearby, e.g. leakage from a pipe
connected to the confined space.
The enclosure and working space may increase other dangers arising through the work being carried out, for example:
• Machinery being used may require special precautions,
such as provision of dust extraction for a portable grinder, or special
precautions against electric shock.
• Gas, fume
or vapour can arise from welding, or by use of volatile and often
flammable solvents, adhesives, etc.
• If access
to the space is through a restricted entrance, such as a manhole,
escape or rescue in an emergency will be more difficult.
What the Law Says
must carry out a suitable and sufficient assessment of the risks for
all work activities for the purpose of deciding what measures are
necessary for safety (The Management of Health and Safety at Work
Regulations 1999). For work in confined spaces this means identifying
the hazards present, assessing the risks and determining what
precautions to take. In most cases the assessment will include
• The task
• The working environment
• Working materials and tools
• The suitability of those carrying out the task
• Arrangements for emergency rescue
The HSE's free leaflet '5 Steps to Risk Assessment' will help guide you through the risk assessment process further.
may need to appoint competent people to help manage the risks and
ensure that employees are adequately trained and instructed (The
Management of Health and Safety at Work Regulations 1999).
your assessment identifies risks of serious injury from work in
confined spaces, such as the dangers highlighted above, the Confined
Spaces Regulations 1997 apply. These regulations contain the following
• Avoid entry to confined spaces, e.g. by doing the work from outside.
• If entry to a confined space is unavoidable, follow a safe system of work.
• Put in place adequate emergency arrangements before the work starts.
Areas to Include for Consideration
• Avoid entering confined spaces
• Development of a safe system of work
• Appointment of a supervisor
• Are persons suitable for the work?
• Isolation of power sources
• Cleaning before entry
• Check the size of the entrance - access and egress
• Provision of ventilation
• Testing the air quality
• Provision of special tools and lighting
• Provision of escape breathing apparatus
• Preparation of emergency arrangements
• Provision of rescue harnesses
• Two-way communications
• Check how the alarm is raised
• Is a 'permit-to-work' necessary?
• Emergency procedures
• Rescue and resuscitation equipment
• Capabilities and training of rescuers
• Shut down of adjacent plant before attempting emergency rescue
• First-aid procedures
• Local emergency services contact and access
Hazards to Identify in Developing a Safe System of Work / Risk Assessment
• Explosive gases/vapours
• Toxic gases/vapours
• Oxygen content (deficiency / enrichment)
• Explosive gases/vapours
• Fumes, dusts, mists, fogs
• Biological agents
• Entry/exit (access/egress)
• Ventilation systems
• Piping/Distribution systems
• Residual chemicals/materials
• Physical obstacles
• Walking/working surfaces
• Temperature extremes
• Hazardous animals
Work to be performed: Hot work / cold work
• Mental and physical condition of workers
by Dennis Mac (IOSH accredited Unite Safety Rep, retired)
The Confined Spaces Regulations 1997 - Statutory Instrument 1997 No. 1713;
"Safe Work in Confined Spaces", INDG 258, published by the Health & Safety Executive;
"Safe work in confined spaces - Approved Code of Practice, Regulations and Guidance", HSE Books,