Variable & volatile

Variable & volatile

Fire Middle East explores a vital Whitepaper : Understanding the risks of working in confined spaces published by Honeywell Safety Products which explains how to identify a confined space, giving examples and characteristics as well as warning about the specific conditions that come together to create a confined space, which under normal circumstances would not be considered as such. It also considers the physical and atmospheric dangers and the volatile risk factors which may be present.

Working in a confined space is riskier than working in other workplaces as there are many variable and unpredictable factors to be evaluated when looking for hazards. Also, conditions can change very quickly and unexpectedly for the worse. This combination of factors poses a serious health risk to workers, at worst resulting in fatality or serious injury. It also complicates emergency response for rescuers who subsequently put their lives in danger too. 

How to identify a confined space 

A confined space is generally defined as a place that presents specific risks to workers because of its enclosed nature but contrary to popular belief, it doesn’t have to be physically small and many confined spaces can in fact be very large. According to the French National Research and Safety Institute (INRS)2 , a confined space has the following characteristics that are all pointing to a clear and present danger. 

  • Not primarily designed or intended for a human to work in 
  • Has restricted entry and exit, making access, rescue, evacuation, or emergency response activities complicated 
  • Has a hazardous atmosphere
  • Contains substances or material that could trap or engulf someone 
  • Presents a risk to the health and safety of anyone who enters because of work activities being carried out in it or because there are mechanical, electrical, process and safety hazards 

Although some confined spaces are easy to identify, such as a storage tank, silo, sewer or well, others are less obvious. Within the context of the Whitepaper there are two conditions to fulfil for an area to be classified as a confined space. A confined space is not only, as the name suggests, an area that is partially, substantially or fully enclosed but one where there also exists a certain risk of death or serious injury to the personnel working in it and those who may be called upon in case of an emergency. 

What are the dangers? 

Dangers can arise in confined spaces, or change an area into a confined space, because of the following conditions: high and low oxygen level; toxic gas, fume or vapour; presence of free-flowing solids or liquids; fire or explosions from high concentrations of flammable gas, vapour or dust; residues which, if disturbed, can give off toxic gas, fume or vapour; high temperature conditions.

According to recent statistics, the majority of confined space fatalities occur among would-be rescuers because confined spaces are, by definition, difficult to access and dangerous, which makes any rescue operation especially risky. Incidents often occur when workers who have not received appropriate training and are not wearing the correct PPE precipitously enter a confined space to come to a colleague’s rescue. The consequences of such interventions can be severe and range from falls from height to asphyxiation. 

A confined space can not only pose a threat to the workers entering it, but also to their colleagues or members of the public near the entrance where the latter may be exposed to several risks including exhaust fumes and explosions. Therefore, a risk assessment should always account for any workers or members of the public in the vicinity of a confined space. It is also important to take into consideration any external event that may indirectly affect the air quality within a confined space. For example, a power cut affecting ventilation may suddenly put workers inside a confined space at risk. 

Why is a confined space dangerous? 

There are two main types of danger, namely atmospheric hazards and physical hazards. Hazards can already exist or be introduced and arise when the presence of substances and the change in conditions, mixed together, increase the risk to health and safety. All hazards found in a regular workspace can also be found in a confined space. However, the presence of multiple risks combined with difficult rescue operations often aggravate the situation. The types of injuries sustained from confined space accidents include: burns and damages from fire and explosion; poisoning and anoxia; loss of consciousness or asphyxia drowning; heat-related disorders; electrocution; cuts by tools/ machinery moving or rotating parts; and fractures resulting from slips, trips and falls. 

Dangers from atmospheric hazards 


The air in our natural environment contains 20.9 percent oxygen. Asphyxia starts when the concentration of oxygen is approximately less than 17 percent. Low oxygen levels cannot be detected by sight or smell. Common reasons for oxygen deficiency include oxygen displacement, oxidation, i.e. when a metal rusts, combustion during welding or cutting, and bacterial growth that uses up oxygen. Reduced oxygen levels can also arise in poorly ventilated enclosed spaces, such as process plant vessels, silos, ship decks etc. On the other hand, too much oxygen can create other issues. 

Fire and explosion 

Three elements are necessary for a fire or explosion to occur: oxygen, flammable material, and an ignition source. Materials that would not normally catch fire or burn in normal air may do so extremely quickly and easily where there is a high level of oxygen and the risk is extremely high whenever there is a build-up of any flammable gas or vapour. As with oxygen, if the gas or vapour is colourless and odourless, the build-up cannot be detected unless a gas detection instrument is used. Substances that can cause explosions or fires include: 

  • Acetylene gas from leaking welding equipment 
  • Methane and hydrogen sulphide gases produced by rotting organic waste in tanks or sewers 
  • Hydrogen gas produced by contact between aluminium or galvanised metals and corrosive liquids 
  • High concentrations of flour or coal dust 
  • Solvents such as acetone, ethanol, toluene, and xylene, which may have been introduced into the space through spills or by improper use or disposal 

Toxic air 

Chemical asphyxiants prevent the delivery of oxygen from the bloodstream to cells. The most common gases are hydrogen sulphide (H2S) and carbon monoxide (CO). Other instances when toxic air can occur include: evaporation of a liquid in a tank, such as chemicals; when pockets of toxic gas in waste materials are disturbed during cleaning; biological hazards; work activities like grinding, descaling, insulation removal, metal spray applications; leaks from a neighbouring toxic site

Dangers from physical hazards 

The risks associated with physical hazards are widely known within the industry and are certainly avoidable in the context of working in a confined space. Even a noisy environment in a confined space can potentially cause accidents as it impedes communication with support personnel. Falls are another major risk and are one of the main sources of severe injuries but interestingly, what makes confined spaces particularly dangerous is that workers typically operate at relatively low heights. 

Overview of european and national legislation 

The European Union has not introduced any legislation specifically relating to work in confined spaces. However, the Framework Council Directive 89/391/EEC of June 12, 1989 covers all aspects of safety and health at a workplace and countries with extensive, well-regulated industries all have legislation that is similar in principle to that in force in the UK, which is the Confined Spaces Regulations (CSR), 1997.6. In France, CATEC® – the national standard regulating work in confined spaces – was originally created in 2012 to provide obligatory guidelines for all businesses and local authorities in the water treatment and sanitation industries, but it is now used across many industries. It is important to remember that there are also other regulations that apply to work in confined spaces. They cover a broad range of areas including working in mines, lifting operations, exposure to noise and vibration, electrical safety and asbestos. It is the responsibility of safety managers to ensure compliance with all the relevant legislation. 

Safety precautions to manage and reduce risks 

Work in confined spaces is inherently dangerous and must only be conducted by workers who are suitably trained. Besides conducting a risk assessment, there are three basic guidelines of safety precautions for working in confined spaces: ventilation, gas detection and communication. In the first instance, avoid entering the area if the worker is not fully prepared or sufficiently trained. Effective gas detection and communication are also paramount and some of the latest PPE on offer can provide both. 

An appropriate emergency plan before the work starts, including an entry and exit plan for rescuers is vital and however noble it is to want to help co-workers in distress, it is essential not to go in unprepared and risk exposure to the same hazards. No one should enter or work in a confined space unless there are emergency arrangements in place that are appropriate for the risk level. These should include a procedure to extract injured workers from the confined space and first-aid equipment (including resuscitation equipment). Those who are likely to be involved in emergency rescue operations should be trained accordingly. 

Deaths or injuries while working in confined spaces are happening all around the world and the victims are not only the people working in the confined space but the ones who try to rescue them. The negative impacts are huge and besides the tragic loss of human lives, the negligent companies should and do face the full weight of the law.

The Whitepaper also presents several Case Studies, legislation and advice and, in our opinion, is an important contribution to the safety of workers, rescuers and emergency response teams. 

It can be downloaded here