L ANDFALL P REPARATION – G ERMANY

6.17.1 The hazards are similar to those identified in the Russian landfall with additional hazards related to the micro-tunnel construction and environmental concerns related to noise, pollution, silt transportation and seabed contamination.

6.17.2 Hazards related to micro tunnel construction are summarised in the following table

Activity/Hazard Control Measures

Monitor and control rate of advance / excavation / ground movement and surface settlement Manage/control water ingress

Movement of plant above and below ground

Activity/Hazard Control Measures

Tools or materials falling down shaft Access/egress

2 means of access/egress from shafts Lifting Operations

Design of foundations / ground support for craneage operations

Provision of advice, guidance, information and education on occupational health good practice.

Behavioural based safety, focussing on changing operatives behaviour

PIPELINE CONSTRUCTION HAZARDS PIPELINE CONSTRUCTION RISK ASSESSMENT – INCLUDING NORTH OF BORNHOLM OPTION

6.17.3 Noise, light, and exhaust pollution are limited in certain areas of the landfall site and detailed procedures are being developed to ensure these requirements are met. This includes restricting access to construction vessels that meet the noise level requirements. Silt transportation is also of some concern and silt screens will be used to minimise this.

6.17.4 There is a remote possibility that UXO will be unearthed during construction activities as the area has already been surveyed by magnetometer and metal detectors and no objects have been found. Although risk reduction measures will be implemented to reduce the risk to ALARP levels a quantitative assessment of dredging operations has been carried out in section 7.17.

6.17.5 A large number of vessels could be working in the area and therefore there is a potential for collision. However all vessel movements are controlled by the construction manager and the probability of collision is considered to be low. In the worst case any impact would be at low speed and major injury or damage is considered unlikely. It is noted that no collision incidents involving recreational vessels were reported on NSP1.

6.17.6 The risks associated with the preparation of the German landfall are therefore considered to be relatively low. The main concern being to ensure the environmental impact is minimised and that all relevant requirements are met.

The environmental impact has been addressed elsewhere by Ramboll and it is considered that construction risks are relatively low and therefore have not been included in the quantified risk assessment.

6.18 Shore Pull and Shallow Water Pipe lay

6.18.1 In Germany the pull-in will be to microtunnels and in Russia to a cofferdam.

6.18.2 The main hazards related to shore pull and shallow water pipe lay operations are:

• Pipe lay or attendant vessel grounding;

• Failure of pull-in wire or rigging;

• Failure of buoyancy elements;

• Tensioner failure;

• Failure of pull-in winch;

• Adverse weather.

• Vessel collision.

6.18.3 As these operations are carried out in relatively shallow water grounding of any of the vessels involved is a potential hazard which could result in hull damage and pollution. Dredging operations will be carried out to prepare the site for pull-in operations and ensure the water depth is adequate. It is also noted that the pipe lay vessel and supporting vessels used on these operations are generally shallow draft. Water depths are also checked by shallow water survey vessels that carry out bathymetry surveys during dredging operations so the water depths in the area are known. However, the pipe pull-in and lay away is a standard operation and providing it is properly planned and under keel clearance is monitored the associated risks are considered to be low.

6.18.4 At the German Landfall there is a shallow sand bar which will have to be dredged to provide a flotation channel. The maximum allowable dredged depth requires a very shallow draft and a minimum under keel clearance. As the water depth is

weather/wind driven, it will also include a weather window requirement to be assessed in more detail when the contractor and barge is known.

6.18.5 Failure of the pull-in wire or rigging would interrupt the operation while catastrophic failure could result in serious injury to the winch operators onshore and damage to equipment but would have no environmental impact. This is a standard operation and providing it is correctly engineered using normal factors of safety and the equipment is correctly set up and tested this is considered to be a relatively low risk operation.

6.18.6 In the event that one or more buoyancy elements became detached from the pipeline the pull-in load would increase and eventually it would not be possible to continue pulling the pipe ashore. However, the pull-in speed is relatively low and the loads are monitored during the pull so it is unlikely that the pipe or rigging would be overstressed. The main effect would be to delay the operation while the buoyancy modules are re-connected. This is considered to be a low risk.

6.18.7 In the event of a tensioner failure the pipe lay operation would cease while the failed unit is repaired. Tensioners are designed to fail to the brakes-on position and the pipe should not move as a result of this failure. If it was necessary to open a tensioner for repair then the load may be supported by the other tensioners if the load is within their capacity. If not the load would need to be transferred to the A&R winch and the pipe eventually laid down if required.

6.18.8 Failure of the pull-in winch would result in a delay while the equipment is repaired but is unlikely to result in personnel injury unless the failure caused a rapid release of pull-in tension. Winch failure is unlikely to cause environmental damage.

6.18.9 Adverse weather would delay the operation if it exceeded the pre-determined criteria. Depending on the severity of the conditions it should be possible to maintain tension but in the worst case it would be necessary to lay the pipe down and remove buoyancy elements if pipe movement was excessive. Provided operations are carried out in accordance with the weather criteria it is considered that the probability of injury or environmental damage as a result of adverse weather is low.

6.18.10 A number of anchor handlers, survey vessels, line pull vessels etc. are involved in shore pull and shallow water pipe lay operations and there is a potential for collision. However all vessel movements are controlled by the construction manager and the probability of collision is considered to be low. In the worst case any impact would be at low speed and major injury or damage is considered unlikely.

6.18.11 It is noted that the German Landfall is in a very popular leisure sailing area with lots of marinas in the surrounding area. Most private sailing boats are not equipped with AIS and are therefore not accounted for in any traffic statistics. As in NSP1, NSP2 will employ Guard Vessels (probably local fishermen like on NSP1) to watch out and inform sailors during the dredging/pipe lay/backfilling campaign.

6.18.12 It is therefore considered that risks related to shore pull and shallow water lay are low and will not be included in the quantified assessment.