What are Confined Spaces?

Confined spaces are locations with restricted access and ventilation where employees have to work under special conditions. Examples include tanks, cellars, pipework, wells, silos, engine rooms and more. These spaces can have hazardous atmospheric conditions due to the presence of toxic gases, oxygen deficiency or explosive vapours.

Hazards in Confined Spaces

Working in confined spaces involves a variety of risks.

A lack of oxygen in confined spaces can be life-threatening because it can lead to asphyxiation and loss of consciousness. It is therefore vital to take precautions, such as good ventilation, regular monitoring of air quality and the use of personal protective equipment such as breathing apparatus, when working in such environments.

1. Lack of Oxygen: One of the greatest hazards is a shortage of oxygen, which can cause asphyxiation.

   In confined spaces a lack of oxygen can occur for various reasons. Confined spaces generally have limited access to fresh air from outside. If there is insufficient ventilation, the oxygen present can slowly be consumed by processes in the space, such as combustion or biological activity. In metal confined spaces rust formation or corrosion can take place, which uses up oxygen and thus lowers its concentration in the confined space.

2. Toxic Gases: Chemical substances such as hydrogen sulphide or carbon monoxide can be present and are life-threatening when inhaled. On the other hand, in spaces where certain chemicals are present, toxic substances can evaporate. These can be directly toxic when inhaled or react with oxygen and reduce its concentration. In addition, toxic gases that displace oxygen can be present in confined spaces. Sometimes toxic gases are 'heavier' than oxygen, causing the toxic gases to accumulate in lower spaces, such as a cellar. Finally, the breakdown of organic material in enclosed spaces can lead to the production of so-called manure gases (hydrogen sulphide, carbon dioxide, methane or ammonia). Some microbial processes also take place by consuming oxygen.
   
   
3. Fire and Explosion Hazard: A build-up of flammable vapours can lead to fire or explosion.
   
   
4. Physical Hazards: Risk of falling objects, entrapment or collapse.

Working Conditions Legislation and Regulations

The Dutch Working Conditions Act obliges employers to take measures to protect employees who work in confined spaces. Some important requirements are:

• Risk Analysis: A detailed risk analysis must be carried out before the work begins.
  
  
• Safe Working Procedures: Drawing up and complying with safe working procedures for working in confined spaces.
  
  
• Training and Supervision: Employees must be trained in confined space procedures and the work must be supervised.
  
  
• Suitable Equipment: Use of suitable personal protective equipment and gas detectors.
  
  
  

For instance, Article 3.5g of the Dutch Working Conditions Decree states: 'If it can be suspected that the atmosphere in a place or in a space contains substances to such an extent that this creates a danger of asphyxiation, narcosis, poisoning, fire or explosion, the employee may only be present in that place or in that space if investigation shows that the danger is not present.'

There is in any case a case of:

1. Danger of asphyxiation if the atmosphere contains less than 18 per cent oxygen by volume;
   
   
2. Danger of narcosis or poisoning if the concentration of the substances concerned in the atmosphere is higher than the limit value for the specific gas in your confined spaces;
   
   
3. Danger of fire or explosion if the concentration of oxygen in the atmosphere is higher than 21 per cent by volume or the concentration of flammable gases or vapours is higher than 10 per cent by volume (vol%) of the lower explosive limit.

It is also stated: 'If the investigation referred to in the first paragraph shows that a danger of asphyxiation, narcosis, poisoning, fire or explosion is present, effective measures shall be taken so that the employee can be present in that space, referred to in the first paragraph, without danger.'

In short, what article 3.5g of the Working Conditions Decree means is:

1. The employee must be able to enter a confined space safely. not only be able to enter safely.
2. While working in confined spaces the employee must also remain safe there for the duration of the work.

This means that before entering a confined space, a gas measurement must be carried out to be certain that there are no hazardous gases in the confined space. And that gas must then also be monitored during the work in the confined space so that the employees can carry out their work safely.

Gas detectors for safer working in confined spaces

Gas detectors are crucial for working safely in confined spaces. These devices detect and warn of the presence of toxic gases and oxygen deficiency. Various types of gas detector are available, such as:

• Single gas detectors: For detecting specific gases such as carbon monoxide, hydrogen sulphide, or flammable gases. These are attached to workwear and provide continuous monitoring.
  
  
• Multi gas detectors: Which can detect several types of gas at the same time. These are attached to workwear or are also available as a handheld meter with pump. This allows a confined space to be cleared before it is entered.
  
  
• Transportable gas detectors: For area monitoring and continuous monitoring of confined spaces.

Correct use of gas detectors can save lives by giving timely warning of hazardous atmospheric conditions.