General

• A confined space is any enclosed space, above or below ground, where a responsible foreseeable risk exists such as a lack of oxygen, the presence of a suffocating, toxic or flammable atmosphere, flooding, or some other potentially hostile environment.
• Places potentially coming within this definition include cellars; chambers; vats; process vessels; pits; tanks; flues; underground rooms; ducts; silos; boreholes; manholes; sewers; drains; pipes; boilers; shafts; tunnels; sumps and some excavations.
• It is an employer’s responsibility to identify confined spaces, which may be hazardous and to establish safe systems of work.
  

Oxygen Deficiency

• A shortage of oxygen causes loss of co-ordination and concentration; abnormal fatigue; and unconsciousness, which can result in death.
• It may be the result of:
  • the oxygen being displaced by gas leaking from elsewhere or the deliberate introduction of gas for purging.
  • oxidisation, rusting or bacterial growth using up the oxygen in the air.
  • oxygen being consumed by people working and breathing, or by any process of combustion.
    

Toxic Atmospheres

• ​​​​​​​hydrogen sulphide, usually from sewage or decaying vegetation.
• carbon monoxide from internal combustion engines, or any incomplete combustion, especially of LPG.
• carbon dioxide from fermentation, or naturally evolved in soil and rocks, or from the combustion of LPGs.
• vapors from chemicals such as ammonia; chlorine; sodium; and from petrol and solvents, usually as a result of leakage or spillage.
  

Flammable Atmospheres

A few of the major sources of explosive and flammable atmospheres are:

• petrol or LPG vapor.
• methane; hydrogen sulphide; naturally evolved from sewage or decaying organic matter.
• solvents; acetone; toluene; white spirit; alcohol and benzene.
• hydrogen and other gases evolved from processes such as battery charging
  

Safe Working

The employer’s safe system of work may include:

• the operation of a Confined space permit-to-work procedure.
• isolation of the space from sources of danger.
• cleansing the space of harmful substances.
• purging and ventilation.
• monitoring the atmosphere.
• communications.
• the use of special tools and equipment.
• special training for operatives.
• rescue procedures and equipment.
• If you are required to enter a confined space, which your employer has identified as being potentially hazardous, you must only do so strictly in accordance with training and/or instructions received, and in accordance with any permit-to-work procedure that has been established.
• If a person in injured in a confined space, which has been certified safe to enter without breathing apparatus, an entry can be made to rescue and remove him straight away.
• If a person collapses in a confined space and the cause is not known, no-one must enter unless they are wearing breathing apparatus in accordance with the established emergency procedures.
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Working in Sewers

• In no circumstances must you enter any sewer, or manhole, chamber or sump, connected with a live sewer unless the necessary safety precautions have been taken, including following the confined space procedures.
• Even if there is an emergency and you think that lives may be at stake, you must still follow the safety procedure.
• Physical injuries in sewers are generally caused by tools or other articles being dropped down a manhole onto men below, or by men themselves slipping from ladders.
• Always wear your safety helmet and harness.
• The safe system of work established by your employer should include tests of the atmosphere, either continuously or at frequent intervals.
• If dangerous conditions are indicated, or if you feel sick or dizzy, leave the sewer at once.
• A rise in water level, sudden breeze in a sewer, or the onset of heavy rain may give warning of possible flooding. If this happens, leave the sewer at once.
• Bacterial infection from rats’ urine can occur to persons who work in sewers. This is known as Weil’s disease, which can enter the body through breaks in the skin, or be ingested through eating, drinking or smoking with dirty hands, or be inhaled in water droplets.
• If you cut yourself during your work, or have a wound, however slight, you must get immediate first-aid treatment.
• The early stages of Weil’s disease may be rather like the ‘flu', so if you go to a doctor you should always make sure that he knows where you have been working.
• Always clean thoroughly any cut or scratch of the skin immediately it has happened. Apply antiseptic to the wound and protect it with gauze and an adhesive plaster.
• Before working, all cuts and abrasions must be covered with waterproof plaster.
• Remember - it is most important that you follow the procedures - while at work, and in an emergency