General rules

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 and for our external contractors. 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 may only commence following permission from Gasunie. For some activities, Gasunie will first secure the installation or section of the installation. You must at all times familiarise yourself with the situation at the location where the work is to be carried out as soon as possible. For example, who/what is where? Is the installation in use? Read your work permit carefully and make sure that the control measures described are in place or have been carried out. If anything is unclear, ask the person who has issued the work permit. Then take 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. Systems under high pressure Gas is fed into our pipelines under high pressure by producers and shippers. The gas in our high- pressure grid (HTL) is between 66 and 80 bars and in one or two cases over 100 bars. To enable gas to be transported over large distances, compressor stations are used to bring the gas back to the correct pressure. At metering and pressure-regulating stations (M&R stations) the pressure is reduced from 66 bars to 40 bars. It is at this point, too, that the substance is added to the gas to give it its specific odour. The pipelines containing gas below 40 bars are referred to as the Regional Transport Pipelines (RTP). At the gas receiving stations (GRS), the pressure of the gas is further reduced to the pressure required by the user. This can vary by as much as between 20 and 3 bars. Gas or another medium such as nitrogen can occur at high pressure in all pipelines and systems at locations and installations.

5. What to do during work (control measures) • Make sure before opening installation components, pipelines, a vat or tank you are about to start work on that it is free of liquid, gas and/or that it is not under pressure • Check hoses, fastenings, couplings and safety provisions prior to use (e.g. safety lines, the so-called whip checks or cables) • Use hydraulic/pneumatic tools as prescribed • Roll up any hose you are not using and store it away immediately • Make sure your work permit has been fully completed • Check the work permit to see what measures must be taken • Check the work permit to see what tools can and must be used Report any leaks without delay to the site foreman or your contact/issuer of the work permit. Under no circumstances touch the leak site or the leaked material and do not take any action yourself.

6. Causes of accidents and incidents involving high pressure • Insufficient knowledge of the system • Insufficiently specific release of the work • Unclear designation of the pipeline concerned • Not freely connected system • Failure to secure the valves • Assumption of knowledge/familiarity • Routine approach (“we always do it this way”) • Inadequate or incomplete work specification on the work permit • Unclear instructions What are the dangers associated with leaks? All gases/liquids • Personal injury • Damage to equipment and the environment Toxic gases/liquids • Personal injury on inhalation or contact • Environmental damage

7. Combustible gases/liquids • Danger of explosion on release of gas/air mixture which could be ignited by e.g. open fire, static electricity or other ignition source • Serious personal injury on inhalation or contact • Serious environmental damage • Personal protection equipment (PPE) • Always use the correct personal protection equipment. Use them in the prescribed way and keep • them in good condition. You must protect yourself as follows: • Prescribed antistatic and flame retardant clothing • Safety shoes • Helmet • Safety goggles • Personal gas detection equipment • Gloves • Extra protection measures can be prescribed for work involving specific risks. • These will form part of the work permit.