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. Groundwork Groundwork is very common at Gasunie, both in new construction work and for maintenance, inspections and in response to incidents. Many hours are spent working in trenches and gullies. Some of this work takes place in difficult and often dangerous locations, occasionally under suboptimal weather conditions. This requires an understanding of the right equipment and the application of the correct working methods. But it is above all a question of correctly assessing the risks involved. Remain alert at all times when you are working. If in any doubt, always ask or suspend activities where necessary.

4. Preparation Gasunie’s pipelines are safely located underground, and that is how we want to keep it. Specifications and guidelines have therefore been drawn up with which everyone must abide. The most important are as follows: Before starting work, submit a KLIC (underground network information exchange, WION) notification Before work commences, contact the pipeline route management department to arrange an appointment for supervision Permanent supervision is required during excavation work, pile-driving, drainage and deep ploughing within 4 metres of the pipeline (to be done in consultation with the supervisor) Make a construction drawing, calculation and structural drawing for sheet piling walls Remember that a well or pipeline trench can be vacated on two sides Keep emergency exits free of obstacles Specific excavating guidelines No machine excavation within 50 cms of Gasunie’s gas supply pipelines Only soil suction is permitted on gas supply pipelines and ancillary installations near or within a Gasunie facility/station

5. Ensure: -Safe driving routes -The stability of the ground in the place where you park the soil suction vehicle -A good place for storing the excavated soil -The use of a synthetic suction mouth with a free arm (so called “Hollandse arm”) - The correct partitioning of the site into danger zones Priorities to observe during excavations Remove no more than the top 30 cm layer during machine excavations Manual excavation where there are thought to be underground cables and pipelines Trial trenches for localising cables and pipelines must also be dug by hand If there are signs of soil contamination or explosives, work must be suspended Excavated earth must be carefully stored: not over a pipeline and at least 50 cms away from the edges of the work trench

6. Risks associated with working in pits and trenches Collapsing of slopes Collapsing of sheet piling structures Overbalancing of hoisting equipment Flooding (ground or rainwater) Inability to evacuate fast enough in the event of a mishap Damage to cables or pipelines (electricity, gas or liquids) Contaminated soil Characteristics of work trench An excavation in which the width of the bottom of the trench is at least two-thirds of its depth To ensure that the work trench doesn’t become an enclosed space, the length and width (measured from ground level) must be greater than the depth of the trench (see also the brochure on enclosed spaces) This can be done by digging away the sides of the trench at a sloping angle. The corner profile will depend on the nature of the soil.

7. Specifications governing a safe work trench Safe storage of the excavated soil Edges kept clear (no tools or equipment within at least 50 cms) Work floor must be kept dry. The ideal trench floor base is sand with a drain underneath Each work trench must be equipped with at least two good escape routes Placing of ladders or excavating of escape routes

8. Key requirements for work trenches Guard against damage to own and third party pipelines (excavation code, KLIC, supervision) Ensure adequate space in and around the work trench Make the escape routes and keep them free of obstacles Do not make the trench deeper than is necessary (prevent creation of confined space) Ensure a good slope to the trench Where necessary, erect a wall of sheet or piling Do not pile excavated soil immediately next to the trench Ensure proper cordoning off of the excavated trench Ensure adequate lighting where necessary Check the trench following adverse weather The ideal work trench Ladder well point system Ladder level sandy ground correct slope

9. Priorities for earth-retaining constructions Put in place earth-retaining structures (in the form of stapling, plank mouldings or sheet piling) Always start by making a construction drawing and calculation Daily checks (especially after bad weather). Repair immediately if necessary Remove structures only when the risk of collapse has abated Priorities to observe when cordoning off the trench Cordon off at least 50 cms from the trench edge Statutory obligations are laid down in the Health and Safety Decree Implementation based on a risk inventory In principle, three types of cordoning off: – Fencing (to keep the public outside the construction area). At least 2 metres high, supported and secured to prevent lifting – “Full screen” protection against the risk of falling. At least 1 metre high and finely-meshed – Tape screen. Red and white (can be crossed) or black and yellow (e.g. non-destructive investigation (NDO)) (cannot be crossed) Also crossings/junctions and platforms (1 metre high)