Areas such as tanks, boilers, sewers, crawl spaces and pipe cellars are usually not easily accessible and therefore cannot be left quickly. Nevertheless, they must be entered frequently, for inspection, cleaning, maintenance and repair, among other things. Working in confined spaces is subject to a number of measures.

If we have to work in a confined space, good ventilation is necessary, because:

1. Gas can be released from the subsurface, especially in swampy areas;
2. Suffocating mixtures may occur when using freon or carbonic freezing equipment;
3. Leaking sewers, gas pipes, burners or cutting devices can cause a flammable, explosive or suffocating gas mixture;
4. Ozone, nitrius fumes, CO and metal oxides may be released during welding operations;
5. Gaseous zinc oxide is released during soldering or welding of plated pipes. It is preferable not to weld, cut or solder as much as possible in crawl spaces or basements. This can be done more safely in the open workplace. Compression fittings or fittings should be used where possible.

Confined spaces are dangerous because:

1. They are poorly accessible;
2. They are poorly ventilated or not ventilated at all;
3. Escape options are limited;
4. Gases or fumes may be generated;
5. There may not be enough oxygen available;
6. Increased risk of electrocution.

When working with fire (welding, cutting, soldering), there are also the following risks:

1. Harmful gases (ozone, nitrous fumes and metal fumes) may be released;
2. When working with fire, a lot of oxygen is extracted from the air;
3. Acetylene or oxygen cylinders may leak. The main hazards are:
   1. Fire and explosion;
   2. Suffocation;
   3. Poisoning;
   4. Electrocution.

• Gas cylinders should never be used in confined spaces.
• Only equipment with a safe voltage (50 volts AC and 120 volts DC) should be used in confined spaces to avoid electrocution.
• Use double-insulated power tools;
• Bring a flashlight for in case the power supply fails;
• No work should be carried out in confined spaces without personal protective equipment.

• The need for personal protective equipment should be determined on a case-by-case basis:

• Self-contained respiratory protective devices (no filter mask!);
• Protective clothing;
• Gloves;
• Safety boots or shoes;
• Eye protection equipment;
• Hearing protection;
• Safety helmet;
• Tank lifebelt, lifeline and possibly a hoist.

​​​​​​​All resources must be well managed, in other words; Cleaned, checked, repaired if necessary and properly stored.

• The diameter of a manhole should be at least 60 cm. A second opening for the introduction of auxiliary material and as an escape route is recommended, also to improve ventilation. If there is less than the usual working space in confined spaces, for example in crawl spaces, then work should be interrupted regularly by staying in a room that is spacious enough in terms of dimensions.
• Make sure that the confined space cannot be accidentally locked.
• Indicate that someone is working in the confined space.
• During the stay in a confined space, 1 person must always be present at the entrance to those spaces (so-called manhole guard), who must maintain contact with the person or persons staying in the confined spaces.
• Barriers should be placed to keep out persons who do not have a job to do at the confined space. Access roads must be kept clear of storage in case of any emergencies.

All parties should be informed in advance, of all issues associated with entering and working in a confined space, such as:

• The (expected) substances;
• The communication procedures;
• The rescue procedures (including ELH);
• Personal protective equipment;
• The use of compressed air plugs or fresh air caps.

If we have to weld or solder in a confined space, the following measures must be taken (in addition to the measures mentioned above):

1. No gas or oxygen cylinders and manifolds in the room;
2. Check the pipes for leaks;
3. Provide fire extinguishers in the workplace. Do not use carbon dioxide snow - extinguishers. This is because the extinguishing principle of a carbon dioxide snow extinguisher is based on oxygen displacement, which creates a risk of suffocation in confined spaces;
4. Depressurize gas pipes that are being worked on and, if necessary, flush with an inert gas and make sure that the gases do not flow into the rooms;
5. If polystyrene is used (as an insulation material), this poses an increased risk, because the polystyrene easily catches fire, it is highly flammable and the fire spreads quickly. Therefore, in such situations, the following applies:
   1. The free space under the polystyrene should be at least 60cm;
   2. The escape route must be free and easy to navigate
   3. Remove the insulation as much as possible and what cannot be removed must be shielded with non-combustible material.

Criteria for safe confined space entry are:

1. Oxygen concentration: 20-21% by volume (vol.%);
2. Concentration of explosive gases and fumes must be less than 10% of the lowest concentration at which an explosion can occur;
3. Concentration of toxic substances should be lower than the exposure limit values. This is the maximum value below which you can work without causing health problems.

With a multi-gas detector, these things can be measured before entering the confined space.

The measurements must be carried out at different places in the room, because this can vary considerably from place to place. One should always start measuring outside the room.

If desired, the QHSE department can advise on the purchase and use of such a multi-gas detector.

Talk to each other about the following:

1. Do you ever work in a confined space?
2. Were you aware of the risks and measures?
3. Are you unsure whether or not the space should be considered as a confined space? Then ask your manager.