2. Gasunie is one of the biggest gas infrastructure companies in Europe. Within the company, we give safety the highest priority; it forms the basis of our license to operate. We abide by the strictest safety, health and environmental standards, both for our own employees, external contractors and the surroundings. Gasunie’s safety policy is thus characterised by a proactive approach which is designed to prevent accidents, incidents and hazardous situations.

3. General rules Work can only begin following permission from Gasunie. Some activities will require Gasunie to secure the installation or the section before work can begin. You must always familiarise yourself with the situation at the location where you will be working as soon as possible; who/what is where? Is the installation in operation? Read your work permit carefully and make sure the control measures described are in place. If anything is unclear, ask the issuer of the work permit. Then put in place the precautionary measures that are appropriate to the work you are about to carry out. Remain alert at all times when you are working. If in any doubt, always ask or suspend activities where necessary.

4. Hazards of working in confined spaces What makes working in confined spaces so risky? Confined spaces often contain liquid, gas or vapour residues which, either alone or in combination, are toxic, flammable or explosive There is often not enough oxygen in confined spaces Confined spaces are often difficult to get into (usually only through a small aperture such as a manhole or a crawl space). If an accident occurs, this will lead to major problems and rescuing people will be very difficult Confined spaces are often difficult to ventilate Confined spaces often contain obstacles such as pipelines and/or supporting beams

5. Examples of confined spaces include: Crawl spaces under buildings Manure cellars and liquid manure tanks on agricultural premises Sewage systems Trenches containing pipelines Work trenches Reaction boilers and storage tanks, e.g. in the (petro)chemicals industry Tankers for transporting liquids, solids and gases Double walled and other storage areas on ships, e.g. bulkhead spaces or ballast tanks Gas freight containers Not all work trenches and pipeline gullies need to be designated as confined spaces. As well as their dimensions, the possible presence of the aforementioned risks is also an important factor. Clear communication about this between those involved is necessary.

6. Possible risks/consequences Confined spaces may contain hazardous atmospheres (or else such atmospheres can be generated through work activities), causing a potentially life-threatening situation or serious risk to health either in these spaces or near the openings to them. These risks are as follows: asphyxiation intoxication or poisoning fire or explosion gas or dust explosions There are also one or two dangers relating to the nature and shape of the space/room or the character of the work to be carried out. These dangers are as follows: moving parts electrical current (risk of electrocution) falling, slipping and falling objects tripping over obstacles When working in confined spaces, several of the aforementioned hazards can usually occur simultaneously.

7. Rules governing safety Under normal conditions, confined spaces are sealed off from the outside but are regularly entered for the purposes of making inspections and repairs and for cleaning and maintenance. Before a confined space can be entered, it must first be investigated to establish a possible risk of poisoning, asphyxiation, intoxication, fire or explosion. The investigation must look at the risks relating to all the hazards that could occur in this particular space. Appropriate measures must then be taken to control the associated risks based on this survey. The working area must also be as free as possible of obstacles. Due to the increased risks of working in confined spaces, it is necessary to make a proper assessment of the activities involved. The TRA (task risk analysis) is highly suitable for the purpose. It divides the work into a number of logical process stages, identifies the risks at each stage and formulates appropriate measures.

8. There are three types of measures we can take: measures to control the atmosphere in a confined space (‘to measure is to know’) control measures to mitigate the risk of moving parts, electrocution, falling, slipping and falling objects organisational measures such as designating a work foreman, instructing staff who are entering the confined space, appointing a manhole supervisor and fixing warning labels to the entrances of the space concerned

9. Approval Gasunie’s Operations department has a list of the confined spaces at each location. If work has to be carried out in a confined space, the TRA that has been drawn up for the work concerned must be linked to the work permit. The TRA will be discussed and approved prior to the issuing of the work permit. If the work in confined spaces relates to new construction work, the TRA will be discussed with, and submitted to, the main supervisor for his approval. Own responsibility Before entering a confined space, you must always satisfy yourself that all measures have been taken to carry out the work safely. Here again, the motto ‘think before you act’ applies in particular! If you have any doubts or are unclear about anything, ask! Contact the issuer of the work permit or the work supervisor.