Ken Smith looks at the hidden dangers of working in confined spaces and offers guidance on how to identify the risks and the types of training required to prevent accidents occuring.
The Confined Spaces Regulations 1997
define a confined space as one that is substantially (though not always entirely) enclosed, and for which there is a reasonably foreseeable risk of serious injury from hazardous substances or conditions within the space, or nearby.
Most fatalities can be prevented by applying knowledge or training, so why are confined-space fatalities still occurring?
Identifying a confined space
Some confined spaces are easy to identify — for example, enclosures with limited openings such as reaction vessels, enclosed drains, sewers, storage tanks and silos, boilers, combustion chambers in furnaces, and ductwork.
While the oil and gas, utilities and manufacturing industries might seem the obvious locations for confined-space working, confined areas can, in fact, occur in any void, as well as plant rooms, service ducts, or poorly ventilated rooms.
Some confined spaces will also develop during construction — for example, the assembly of a tank, or process plant, particularly where welding takes place on the inside. These spaces are equally as hazardous as those found in industrial environments, so it is essential that safe systems of work are implemented in every workplace, with facilities managers and employees alike made fully aware of the dangers. After all, it is only through understanding the risks that employers and managers are able to make informed decisions about the correct training, personal protective equipment and controls required to ensure a safe working environment.
What the law expects
The Confined Spaces Regulations 1997 specifically pertain to the identification and management of confined-space working. Published with an accompanying Approved Code of Practice (ACoP) (HSE L101),2
the Regulations apply to all premises covered by the HSWA 1974, with the exception of mines and diving operations.
The Regulations and the ACoP must be considered before any attempt is made to enter a confined space. Indeed, one of the key requirements of the Regulations is for employers to find a reasonably practicable method of completing the work in the confined space without entry.
Of course, the requirements of the HSWA 1974 and the MHSWR 1999
would also have to be considered in the preparation of any risk assessment and safe system of work, including training. Other legislation may also be relevant depending on the work to be carried out in the confined space, where hazards such as electricity and dangerous substances may be present and work-at-height and manual-handling risks may manifest.
Personal protective clothing and respiratory protective equipment may be specified and used in confined spaces, which will mean the relevant regulations relating to their provision and maintenance, as well as associated training, will also have to be considered.
Confined spaces pose a wide variety of potential hazards. They are often poorly ventilated and not only can they contain gases and other harmful substances but escape, or rescue from them can be problematic. The major hazards that workers should be made aware of are:
The cramped conditions of confined spaces present a significant health and safety risk. The use of breathing apparatus, harnesses and rescue equipment becomes much more difficult to negotiate and often movement is restricted, so it is essential that workers have equipment of the correct size before entry.
Poisonous gases and fumes
Arguably, the most common hazard when working in confined spaces is the presence of poisonous gases, fumes or vapours. Toxic gases or vapours can be formed by the processes of cleaning, welding or painting, which, in an unventilated space, can poison and suffocate the worker. In excavation work, contamination could result from hazardous substances previously deposited in the ground, or from natural sources, such as carbon dioxide produced from limestone.
Some gases may also become trapped in residues and sludge, scale, or animal waste, which may not be identified by atmospheric tests but could be easily disturbed and released by workers. In addition, toxic gases will not necessarily originate from within the confined space itself; fumes may also filter in from outside sources, such as nearby processes, or car exhausts.
Oxygen deficiency or excess
Levels of oxygen can be depleted by oxidisation, rusting, fire, growth of bacteria, or the displacement of oxygen by another gas. The normal oxygen level in air is 20.9 per cent and monitoring equipment should alarm when the level drops to 19.5 per cent.
Anything below this level can quickly affect the functioning of the brain, causing drowsiness and reducing a person’s ability to respond to their environment. Oxygen levels below 16 per cent can result in unconsciousness, or even death. Conversely, excess oxygen, caused by leaking oxy/fuel gas, cutting or welding equipment, also presents a serious threat to workers by increasing the risk of fire in otherwise safe materials, such as clothing. The monitoring equipment should alarm at 23.5 per cent to indicate the possibility of an oxygen-enriched atmosphere.
Overheating of the body can cause heat stroke, unconsciousness and death. Excessive levels of heat can be generated by inadequate ventilation, incorrect clothing and the use of steam and hot-water jets commonly used in industrial cleaning. In spaces such as ovens or boilers, residual heat may linger, so, in cases like these, it is vital that the confined space has had sufficient time to cool before entry.
Dangers can also arise in confined spaces from the build-up of flammable gases, fumes, vapours or dusts. Once again, these may originate from the confined space itself, or from work carried out inside. Where there is potential for the presence of flammable substances, suitable equipment must be specified to eliminate any risk of a spark, or ignition source.
It is a requirement that suitable and sufficient arrangements for rescuing an incapacitated person from a confined space are in place before the work begins. This will include having in place sufficient equipment and trained personnel to carry out a rescue. Consideration should be given not only to the specified hazards detailed in the ACoP but to all foreseeable injuries, or situations — for example, a broken ankle sustained as a result of a fall.
The required training for confined-space rescue teams, detailed in the Confined Spaces Regulations 2007, covers a number of aspects, including:
- the use of rescue equipment — for example, breathing apparatus, lifelines, and, where necessary, a knowledge of their construction and how they work;
- checking of correct functioning and/or testing of emergency equipment (for immediate use and to enable specific periodic maintenance checks);
- identifying defects and dealing with malfunctions and failures of equipment during use;
- works, site, or other local emergency procedures, including initiation of an emergency response;
- resuscitation procedures and, where appropriate, the correct use of relevant ancillary equipment and any resuscitation equipment provided (if intended to be operated by those receiving emergency-rescue training);
- emergency first aid and the use of the first-aid equipment provided;
- use of fire-fighting equipment; and
- rescue techniques, including regular and periodic rehearsals/exercises. These could include the use of a full-weight dummy.
Most importantly, training should be realistic and not just drill-based. It should relate to practice and familiarity with equipment, surroundings and possible emergency scenarios.
Ensuring safe working practices
Following hazard and risk assessment, all workers — including managers, supervisory staff, risk assessors and rescue personnel — must be given appropriate training and distributed the correct PPE.
By implementing the following simple steps, confined-space hazards can be minimised: testing the atmosphere for flammable and toxic gases; ensuring the provision of special tools, lighting and breathing apparatus; and having in place rehearsed emergency procedures.
Confined-space workers should always be monitored and supervised by outside personnel. Like the confined-space workers, the supervisory staff should also be trained in safe working practices and be equipped with harness, lifeline and protective equipment so they can react quickly in an emergency.
Confined-space operatives must be able to recognise, enter and work safely within a confined space, and be familiar with the correct PPE and other related safety devices. But it is only through realistic and thorough training that these skills and knowledge can be gained.
Full training will need to cover the avoidance of confined-space entry, the need to take necessary precautions upon entry, safe working practices, and steps to be undertaken in emergencies. Practical demonstrations and exercises will give participants a more realistic experience and have been proven to better prepare them when dealing with an emergency situation.
Furthermore, practical training within a simulated, confined safe environment can overcome many of the initial fears and concerns individuals may have. Regular drills and periodic reviews should ensure that training is always kept up to date and fresh in the minds of operatives.
Such an approach, coupled with risk awareness, will help reduce confined-space fatalities and go a long way to ensuring the health and safety of your workforce.
Ken Smith CMIOSH RMaPS is a senior consultant with Arco Training and Consultancy.
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